|IM (approved), SC, intradermal, into glands|
|ATC code||M03AX01 (WHO)|
|Molar mass||150 kg/mol (150,000 g/mol)|
|(what is this?)|
|PDB structures||RCSB PDB PDBe PDBsum|
|Gene Ontology||AmiGO / EGO|
Botulinum toxin (BTX) is a neurotoxic protein produced by the bacterium Clostridium botulinum and related species. Botulinum toxin causes the disease botulism, however it is also used commercially in medicine, cosmetics, and research. There are seven types of botulinum toxin, named type A–G. Type A and B are capable of causing disease in humans, and are also used commercially and medically. Types C–G are less common; types E and F can cause disease in humans, while the other types cause disease in other animals. Botulinum toxin types A and B are used in medicine to treat various muscle spasms and diseases characterized by overactive muscle. The U.S. Food and Drug Administration requires a boxed warning stating that when locally administered the toxin may spread from the injection site to other areas of the body, causing botulism. The warning was the result of deaths associated with its uses. Infection with the bacterium may result in a potentially fatal disease called botulism. Botulinum is the most acutely lethal toxin known, with an estimated human median lethal dose (LD50) of 1.3–2.1 ng/kg intravenously or intramuscularly and 10–13 ng/kg when inhaled.
- 1 Medical uses
- 2 Side effects
- 3 Role in disease
- 4 Mechanism of action
- 5 History
- 6 Society and culture
- 7 Research
- 8 See also
- 9 References
- 10 External links
Botulinum toxin is used to treat a number of problems.
When injected in small amounts, it can silence nerves near the injection site, effectively weakening a muscle for a period of two to eleven months. As such, botulinum toxin is used to treat a number of disorders characterized by overactive muscle movement, including spasms of the head and neck, eyelid, vagina, limbs, jaw, and vocal cords. Similarly, botulinum toxin is used to relax clenching of muscles, including those of the oesophagus, jaw, lower urinary tract and bladder, or clenching of the anus which can exacerbate anal fissure. It may also be used for improper eye alignment.
In cosmetic applications, botulinum toxin is considered safe and effective for reduction of facial wrinkles, especially in the uppermost third of the face. Injection of botulinum toxin into the muscles under facial wrinkles causes relaxation of those muscles, resulting in the smoothing of the overlying skin. Smoothing of wrinkles is usually visible three days after treatment and is maximally visible two weeks following injection. The treated muscles gradually regain function, and generally return to their former appearance three to four months after treatment. Muscles can be treated repeatedly to maintain the smoothed appearance.
Botulinum toxin is also used to treat disorders of hyperactive nerves including excessive sweating, neuropathic pain, and some allergy symptoms. In addition to these uses, botulinum toxin is being evaluated for use in treating chronic pain.
While botulinum toxin is generally considered safe in a clinical setting, there can be serious side effects from its use. Most commonly, botulinum toxin can be injected into the wrong muscle group or spread from the injection site, causing paralysis of unintended muscles.
Side effects from cosmetic use generally result from unintended paralysis of facial muscles. These include partial facial paralysis, muscle weakness, and trouble swallowing. Side effects are not limited to direct paralysis however, and can also include headaches, flu-like syndromes, and allergic reactions. Just as cosmetic treatments only last a number of months, paralysis side-effects can have the same durations. At least in some cases, these effects are reported to dissipate in the weeks after treatment. Bruising at the site of injection is not a side effect of the toxin but rather of the mode of administration, and is reported as preventable if the clinician applies pressure to the injection site; when it occurs, it is reported in specific cases to last 7–11 days. When injecting the masseter muscle of the jaw, loss of muscle function can result in a loss or reduction of power to chew solid foods.
Side effects from therapeutic use can be much more varied depending on the location of injection and the dose of toxin injected. In general, side effects from therapeutic use can be more serious than those that arise during cosmetic use. These can arise from paralysis of critical muscle groups and can include arrhythmia, heart attack, and in some cases seizures, respiratory arrest, and death. Additionally, side effects which are common in cosmetic use are also common in therapeutic use, including trouble swallowing, muscle weakness, allergic reactions, and flu-like syndromes.
In response to the occurrence of these side effects, in 2008 the U.S. FDA notified the public of the potential dangers of botulinum toxin as a therapeutic. Namely, they warned that the toxin can spread to areas distant from the site of injection and paralyze unintended muscle groups, especially when used for treating muscle spasticity in children treated for cerebral palsy. In 2009, the FDA announced that boxed warnings would be added to available botulinum toxin products, warning of their ability to spread from the injection site. Additionally, the FDA announced name changes to several botulinum toxin products, meant to emphasize that the products are not interchangeable and require different doses for proper use. Botox and Botox Cosmetic were renamed onabotulinumtoxinA, Myobloc was renamed rimabotulinumtoxinB, and Dysport name renamed abobotulinumtoxinA. In conjunction with this, the FDA issued a communication to health care professionals reiterating the new drug names and the approved uses for each. A similar warning was issued by Health Canada in 2009, warning that botulinum toxin products can spread to other parts of the body.
Role in disease
Botulinum toxin produced by Clostridium botulinum is the cause of botulism. Humans most commonly ingest the toxin from eating improperly-canned foods in which C. botulinum has grown. However, the toxin can also be introduced through an infected wound. In infants, the bacteria can sometimes grow in the intestines and produce botulinum toxin within the intestine. In all cases, the toxin can then spread, blocking nerves and muscle function. In severe cases, the toxin can block nerves controlling the respiratory system or heart, resulting in death. Botulism can be difficult to diagnosis, as it may appear similar to diseases such as Guillain–Barré syndrome, myasthenia gravis, and stroke. Other tests, such as brain scan and spinal fluid examination, may help to rule out other causes. If the symptoms of botulism are diagnosed early, various treatments can be administered. In an effort to remove contaminated food which remains in the gut, enemas or induced vomiting may be used. For wound infections, infected material may be removed surgically. Botulinum antitoxin is available and may be used to prevent the worsening of symptoms, though it will not reverse existing nerve damage. In severe cases, mechanical respiration may be used to support patients suffering from respiratory failure. The nerve damage heals over time, generally over weeks to months. With proper treatment, the case fatality rate for botulinum poisoning can be greatly reduced.
Two preparations of botulinum antitoxins are available for treatment of botulism. Trivalent (A,B,E) botulinum antitoxin is derived from equine sources using whole antibodies. The second antitoxin is Heptavalent (A,B,C,D,E,F,G) botulinum antitoxin, which is derived from equine antibodies which have been altered to make them less immunogenic. This antitoxin is effective against all known strains of botulism.
Mechanism of action
|This section needs additional citations for verification. (February 2015) (Learn how and when to remove this template message)|
The toxin produced by Clostridum species is a two-chain protein composed of a 100-kDa heavy chain polypeptide joined via disulfide bond to a 50-kDa light chain polypeptide. The seven serologically distinct toxin types possessing different tertiary structures and significant sequence divergence are designated A to G. The A, B, and E serotypes cause human botulism, with the activities of types A and B enduring longest in vivo (from several weeks to months).
The terminals of specific axons must internalize the toxin to cause paralysis, and the heavy chain of the toxins is implicated in targeting the toxin to such axon terminals; following the attachment of the toxin heavy chain to proteins on the surface of the terminals, toxin molecules enter the neurons by endocytosis. The light chain, which has zinc metalloprotease activity, is released from the endocytotic vesicles and reaches the cytoplasm.[clarification needed] Specific serotypes of the toxin cleave synaptosomal-associated protein (25 kDa) (SNAP-25), a protein from the soluble N-ethylmaleimide-sensitive factor attachment receptor (SNARE) family involved in vesicle fusion and mediating release of neurotransmitter, in particular acetylcholine, from axon endings.[non-primary source needed] Cleavage of the SNARE proteins inhibits release of acetylcholine. Hence, botulinum toxins A, B, and E specifically cleave SNAREs, preventing "neurosecretory vesicles" from docking/fusing with the interior surface of the plasma membrane of the nerve synapse, and so block release of neurotransmitter. In inhibiting acetylcholine release, nerve impulses are blocked, causing the flaccid (sagging) paralysis of muscles characteristic of botulism (in contrast to the distinct spastic paralysis seen in tetanus).
In 1820, Justinus Kerner, a small-town German medical officer and romantic poet, gave the first complete description of clinical botulism based on extensive clinical observations of so-called “sausage poisoning”. Following experiments on animals and on himself, he concluded that the toxin acts by interrupting signal transmission in the somatic and autonomic motor systems, without affecting sensory signals or mental functions. He observed that the toxin develops under anaerobic conditions, and can be lethal in minute doses. His prescience in suggesting that the toxin might be used therapeutically earned him recognition as the pioneer of modern botulinum toxin therapy.
In 1895 (seventy-five years later), Émile van Ermengem, professor of bacteriology and a student of Robert Koch, correctly described Clostridium botulinum as the bacterial source of the toxin. Thirty-four attendees at a funeral were poisoned by eating partially salted ham, an extract of which was found to cause botulism-like paralysis in laboratory animals. Van Ermengem isolated and grew the bacterium, and described its toxin, which was later purified by P Tessmer Snipe and Hermann Sommer.
Over the next three decades, as food canning was approaching a billion dollar a year industry, botulism was becoming a public health hazard. Karl Friedrich Meyer, a prodigiously productive Swiss-American veterinary scientist (and supervisor of Alan B. Scott’s mother’s 1925 MA degree in bacteriology), created a center at the Hooper Foundation in San Francisco, where he developed techniques for growing the organism and extracting the toxin, and conversely, for preventing organism growth and toxin production, and inactivating the toxin by heating. The California canning industry was thereby preserved.
With the outbreak of World War II, weaponization of botulinum toxin was investigated at Fort Detrick in Maryland. Carl Lamanna and James Duff developed the concentration and crystallization techniques that Edward J. Schantz used to create the first clinical product. When the Army’s Chemical Corps was disbanded, Schantz moved to the Food Research Institute in Wisconsin, where he manufactured toxin for experimental use and generously provided it to the academic community.
The mechanism of botulinum toxin action – blocking the release from nerve endings of the neurotransmitter acetylcholine – was elucidated in the mid-1900s, and remains an important research topic. Nearly all toxin treatments are based on this effect in various body tissues.
Eye muscle disorders
Ophthalmologists specializing in eye muscle disorders (strabismus) had developed the method of EMG-guided injection (using the electromyogram, the electrical signal from an activated muscle, to guide injection) of local anesthetics as a diagnostic technique for evaluating an individual muscle’s contribution to an eye movement. Because strabismus surgery frequently needed repeating, a search was undertaken for non-surgical, injection treatments using various anesthetics, alcohols, enzymes, enzyme blockers, and snake neurotoxins. Finally, inspired by Daniel Drachman’s work with chicks at Johns Hopkins, Alan B Scott and colleagues injected botulinum toxin into monkey extraocular muscles. The result was remarkable: a few picograms induced paralysis that was confined to the target muscle, long in duration, and without side-effects.
After working out techniques for freeze-drying, buffering with albumin, and assuring sterility, potency, and safety, Scott applied to the FDA for investigational drug use, and began manufacturing botulinum type A neurotoxin in his San Francisco lab. He injected the first strabismus patients in 1977, reported its clinical utility in 1980, and had soon trained hundreds of ophthalmologists in EMG-guided injection of the drug he named Oculinum™ (“eye aligner”).
Strabismus is caused by imbalances in the actions of muscles that rotate the eyes, and can sometimes be relieved by weakening a muscle that pulls too strongly, or pulls against one that has been weakened by disease or trauma. Muscles weakened by toxin injection recover from paralysis after several months, so it might seem that injection would then need to be repeated. However, muscles adapt to the lengths at which they are chronically held, so that if a paralyzed muscle is stretched by its antagonist, it grows longer, while the antagonist shortens, yielding a permanent effect. If there is good binocular vision, the brain mechanism of motor fusion, which aligns the eyes on a target visible to both, can stabilize the corrected alignment.
Other muscle disorders
By 1982, eye muscles had been injected for strabismus and nystagmus (jerky, involuntary eye movements), eyelid muscles for retraction and blepharospasm (sustained, involuntary contractions of muscles around the eye), facial muscles for hemifacial spasm, and limb muscles for dystonia (sustained muscle spasm), all as predicted in Scott’s 1973 study.
Scott also injected the first cases of torticollis (painful, spastic twisting of the neck), which were later published by Joseph Tsui of Vancouver. But even a century and a half after Kerner’s work, it was difficult for many to accept that the specificity and molecular tenacity that made ingested toxin so deadly also made it remarkably safe when injected directly into a target muscle, and no Bay Area neurology, orthopedic, or rehabilitation physician would try toxin for muscle contractures with stroke, dystonia, torticollis, or cerebral palsy. L Andrew Koman of Wake Forest University in North Carolina pioneered use of toxin to treat pediatric leg spasm in cerebral palsy.
Patient groups quickly spread the word that there were now effective treatments for previously untreatable motility disorders such as blepharospasm, which can result in functional blindness despite an otherwise normal visual system. Torticollis patients discovered that their pain could be markedly reduced by toxin injection, motility increased, head position somewhat improved, even if tremor was not. In 1993, Scott, Pankaj Pasricha, and colleagues showed that botulinum toxin could be used for the treatment of achalasia, a spasm of the lower esophageal sphincter. Spasmodic dysphonia (difficulty speaking), various gastroenteric and urinary sphincter spasms, muscle spasm in stroke, and many other muscle disorders, were also treated with botulinum toxin injection.
In January 2014, botulinum toxin was approved by UK's Medicines and Healthcare Products Regulatory Agency (MHRA) for treatment of restricted ankle motion due to lower limb spasticity associated with stroke in adults.
Botulinum toxin has not been approved for pediatric use. However, it has been used off-label for several pediatric conditions, including infantile esotropia and spastic conditions in cerebral palsy.
In 1986, Oculinum Inc, Scott's micromanufacturer and distributor of botulinum toxin, was unable to obtain product liability insurance, and could no longer supply the drug. As supplies became exhausted, patients who had come to rely on periodic injections became desperate. For 4 months, as liability issues were resolved, American blepharospasm patients traveled to Canadian eye centers for their injections.
Based on data from thousands of patients collected by 240 investigators, under the 1983 US Orphan Drug Act, Scott got FDA approval in 1989 to market Oculinum for clinical use in the United States to treat adult strabismus and blepharospasm. Allergan served as the drug’s distributor for almost 2 years, and in 1991 took over the licenses and changed the drug’s name to Botox®.
Richard Clark, a plastic surgeon from Sacramento (CA), was the first to document a cosmetic use for botulinum toxin. He treated facial asymmetry caused by unilateral facial nerve paralysis by injecting toxin into the non-paralyzed frontal muscle.
Marrying ophthalmology to dermatology, Jean and Alistair Carruthers observed that blepharospasm patients who received injections around the eyes and upper face also enjoyed diminished facial glabellar lines (“frown lines” between the eyebrows), thereby initiating the highly-popular cosmetic use of the toxin. Brin, and a group at Columbia University under Monte Keen made similar reports. In 2002, following clinical trials, the FDA approved Botox Cosmetic, botulinum A toxin to temporarily improve the appearance of moderate-to-severe glabellar lines. The FDA approved a fully in vitro assay for use in the stability and potency testing of Botox® in response to increasing public concern that LD50 testing was required for each batch sold in the market.
William Binder reported that patients who had cosmetic injections around the face reported relief from chronic headache. This was initially thought to be an indirect effect of reduced muscle tension, but it is now known that the toxin inhibits release of peripheral nociceptive neurotransmitters, suppressing the central pain processing systems responsible for migraine headache. In 2010, the FDA approved intramuscular botulinum toxin injections for prophylactic treatment of chronic migraine headache.
Society and culture
As of 2013, botulinum toxin injections are the most common cosmetic operation, with 6.3 million procedures in the United States, according to the American Society of Plastic Surgeons. Qualifications for Botox injectors vary by county, state and country. Botox cosmetic providers include dermatologists, plastic surgeons, aesthetic spa physicians, dentists, nurse practitioners, nurses and physician assistants.
The global market for botulinum toxin products, driven by their cosmetic applications, is forecast to reach $2.9 billion by 2018. The facial aesthetics market, of which they are a component, is forecast to reach $4.7 billion ($2 billion in the U.S.) in the same timeframe.
The effects of botulinum toxin are different from those of nerve agents involved insofar in that botulism symptoms develop relatively slowly (over several days), while nerve agent effects are generally much more rapid and can be instantaneous. Evidence suggests that nerve exposure (simulated by injection of atropine and pralidoxime) will increase mortality by enhancing botulinum toxin's mechanism of toxicity.
With regard to detection, current protocols using NBC detection equipment (such as M-8 paper or the ICAM) will not indicate a "positive" when samples containing botulinum toxin are tested. To confirm a diagnosis of botulinum toxin poisoning, therapeutically or to provide evidence in death investigations, botulinum toxin may be quantitated by immunoassay of human biological fluids; serum levels of 12–24 mouse LD50 units per milliliter have been detected in poisoned patients.
Botulinum toxin A is marketed under the brand names Botox (marketed by Allergan), Dysport (marketed by Ipsen), and Xeomin (marketed by Merz Pharma). Botulinum toxin B is marketed under the brand name Myobloc (marketed by Solstice Neurosciences).
In the United States, botulinum toxin products are manufactured by a variety of companies, for both therapeutic and cosmetic use. Allergan, Inc., a principal U.S. supplier through their Botox products, reported in its company materials in 2011 that it could "supply the world's requirements for 25 indications approved by Government agencies around the world" with less than one gram of raw botulinum toxin. Myobloc or Neurobloc, a botulinum toxin type B product, is produced by Solstice Neurosciences, a subsidiary of US WorldMeds. Dysport, a therapeutic formulation of the type A toxin manufactured by Galderma in the United Kingdom, is licensed for the treatment of focal dystonias and certain cosmetic uses in the U.S. and other countries.
After the three primary U.S. manufacturers, there many reports of other sources of production. Xeomin, manufactured in Germany by Merz, is also available for both therapeutic and cosmetic use in the U.S. Lanzhou Institute of Biological Products in China manufactures a BTX-A product; as of 2014 it was the only BTX-A approved in China. BTX-A is also sold as Lantox and Prosigne on the global market. Neuronox, a BTX-A product, was introduced by Medy-Tox Inc. of South Korea in 2009; Neuronox is also marketed as Siax in the U.S.
|This section needs expansion with: clearly referenced sources of therapeutic and BT forms of toxin, and refs. for remainder of pre-existing material. You can help by adding to it. (February 2015)|
Botulism toxins are produced by bacteria of the genus Clostridium, namely Clostridium botulinum, C. butyricum, C. baratii and C. argentinense, which are widely distributed, including in soil and dust. As well, the bacteria can be found inside homes on floors, carpet, and countertops even after cleaning. Some food products such as honey can contain amounts of the bacteria.
Food-borne botulism results, indirectly, from ingestion of food contaminated with Clostridium spores, where exposure to an anaerobic environment allows the spores to germinate, after which the bacteria can multiply and produce toxin. Critically, it is ingestion of toxin rather than spores or vegetative bacteria that causes botulism. Botulism is nevertheless known to be transmitted through canned foods not cooked correctly before canning or after can opening, and so is preventable. Infant botulism cases arise chiefly as a result of environmental exposure and are therefore more difficult to prevent. Infant botulism arising from consumption of honey can be prevented by eliminating honey from diets of children less than 12 months old.
Therapeutic and weaponisable forms of the toxin are sourced from strains of Clostriudium where both the growth and toxin isolation are under specialized conditions.
Organism and toxin susceptibilities
|This section needs expansion with: modern content and referencing on antibiotic susceptibilities. You can help by adding to it. (February 2015)|
Proper refrigeration at temperatures below 3 °C (38 °F) retards the growth of Clostridium botulinum. The organism is also susceptible to high salt, high oxygen, and low pH levels. The toxin itself is rapidly destroyed by heat, such as in thorough cooking. The spores that produce the toxin are heat-tolerant and will survive boiling water for an extended period of time.
The botulinum toxin is denatured and thus deactivated at temperatures greater than 80 °C (176 °F). As a zinc metalloprotease (see below), the toxin's activity is also susceptible, post-exposure, to inhibition by protease inhibitors, e.g., zinc-coordinating hydroxamates.
Blepharospasm and strabismus
In the early 1980s, university-based ophthalmologists in the USA and Canada further refined the use of botulinum toxin as a therapeutic agent. By 1985, a scientific protocol of injection sites and dosage had been empirically determined for treatment of blepharospasm and strabismus. Side effects in treatment of this condition were deemed to be rare, mild and treatable. The beneficial effects of the injection lasted only 4–6 months. Thus, blepharospasm patients required re-injection two or three times a year.
In 1986, Scott's micromanufacturer and distributor of Botox was no longer able to supply the drug because of an inability to obtain product liability insurance. Patients became desperate, as supplies of Botox were gradually consumed, forcing him to abandon patients who would have been due for their next injection. For a period of four months, American blepharospasm patients had to arrange to have their injections performed by participating doctors at Canadian eye centers until the liability issues could be resolved.
In December 1989, Botox, manufactured by Allergan, Inc., was approved by the US Food and Drug Administration (FDA) for the treatment of strabismus, blepharospasm, and hemifacial spasm in patients over 12 years old.
Botox has not been approved for any pediatric use. It has, however, been used off-label by physicians for several conditions. including spastic conditions in pediatric patients with cerebral palsy, a therapeutic course that has resulted in patient deaths. In the case of treatment of infantile esotropia in patients younger than 12 years of age, several studies have yielded differing results.[better source needed]
The cosmetic effect of BTX-A on wrinkles was originally documented by a plastic surgeon from Sacramento, California, Richard Clark, and published in the journal Plastic and Reconstructive Surgery in 1989. Canadian husband and wife ophthalmologist and dermatologist physicians, JD and JA Carruthers, were the first to publish a study on BTX-A for the treatment of glabellar frown lines in 1992. Similar effects had reportedly been observed by a number of independent groups (Brin, and the Columbia University group under Monte Keen.) After formal trials, on April 12, 2002, the FDA announced regulatory approval of botulinum toxin type A (Botox Cosmetic) to temporarily improve the appearance of moderate-to-severe frown lines between the eyebrows (glabellar lines). Subsequently, cosmetic use of botulinum toxin type A has become widespread. The results of Botox Cosmetic can last up to four months and may vary with each patient. The US Food and Drug Administration approved an alternative product-safety testing method in response to increasing public concern that LD50 testing was required for each batch sold in the market.
Upper motor neuron syndrome
BTX-A is now a common treatment for muscles affected by the upper motor neuron syndrome (UMNS), such as cerebral palsy, for muscles with an impaired ability to effectively lengthen. Muscles affected by UMNS frequently are limited by weakness, loss of reciprocal inhibition, decreased movement control and hypertonicity (including spasticity). In January 2014, Botulinum toxin was approved by UK's Medicines and Healthcare Products Regulatory Agency (MHRA) for the treatment of ankle disability due to lower limb spasticity associated with stroke in adults. Joint motion may be restricted by severe muscle imbalance related to the syndrome, when some muscles are markedly hypertonic, and lack effective active lengthening. Injecting an overactive muscle to decrease its level of contraction can allow improved reciprocal motion, so improved ability to move and exercise.
Khalaf Bushara and David Park were the first to demonstrate a nonmuscular use of BTX-A while treating patients with hemifacial spasm in England in 1993, showing that botulinum toxin injections inhibit sweating, and so are useful in treating hyperhidrosis (excessive sweating).[non-primary source needed] BTX-A has since been approved for the treatment of severe primary axillary hyperhidrosis (excessive underarm sweating of unknown cause), which cannot be managed by topical agents.[when?]
BTX-A is commonly used to treat cervical dystonia, but it can become ineffective after a time. Botulinum toxin type B (BTX-B) received FDA approval for treatment of cervical dystonia on December 21, 2000. Trade names for BTX-B are Myobloc in the United States, and Neurobloc in the European Union.
Onabotulinumtoxin A (trade name Botox) received FDA approval for treatment of chronic migraines on October 15, 2010. The toxin is injected into the head and neck to treat these chronic headaches. Approval followed evidence presented to the agency from two studies funded by Allergan, Inc. showing a very slight improvement in incidence of chronic migraines for migraine sufferers undergoing the Botox treatment.
Since then, several randomized control trials have shown botulinum toxin type A to improve headache symptoms and quality of life when used prophylactically for patients with chronic migraine who exhibit headache characteristics consistent with: pressure perceived from outside source, shorter total duration of chronic migraines (<30 years), "detoxification" of patients with coexisting chronic daily headache due to medication overuse, and no current history of other preventive headache medications.
- Montecucco C, Molgó J (June 2005). "Botulinal neurotoxins: revival of an old killer". Current Opinion in Pharmacology. 5 (3): 274–9. doi:10.1016/j.coph.2004.12.006. PMID 15907915.
- American Society of Health-System Pharmacists (October 27, 2011). "Botulinum Toxin Type A". drugs.com. Retrieved 4 March 2015.
- "Fact Sheet: Botulism". World Health Organization. Retrieved 4 October 2016.
- "FDA Notifies Public of Adverse Reactions Linked to Botox Use". Fda.gov. 8 February 2008. Retrieved May 6, 2012.
- "FDA Gives Update on Botulinum Toxin Safety Warnings; Established Names of Drugs Changed". FDA Press Announcement. August 3, 2009. Retrieved 21 September 2016.
- Arnon SS, Schechter R, Inglesby TV, Henderson DA, Bartlett JG, Ascher MS, Eitzen E, Fine AD, Hauer J, Layton M, Lillibridge S, Osterholm MT, O'Toole T, Parker G, Perl TM, Russell PK, Swerdlow DL, Tonat K (February 2001). "Botulinum toxin as a biological weapon: medical and public health management". Jama. 285 (8): 1059–70. doi:10.1001/jama.285.8.1059. PMID 11209178.
- Egan, Matt. "Botox maker bought for $66 billion in biggest deal of 2014". cnn.com. Retrieved 25 October 2015.
- Felber ES (October 2006). "Botulinum toxin in primary care medicine". The Journal of the American Osteopathic Association. 106 (10): 609–14. PMID 17122031.
- "Cervical dystonia". Mayo Clinic. 2014-01-28. Retrieved 2015-10-14.
- Shukla HD, Sharma SK (2005). "Clostridium botulinum: a bug with beauty and weapon". Critical Reviews in Microbiology. 31 (1): 11–8. doi:10.1080/10408410590912952. PMID 15839401.
- Pacik PT (December 2009). "Botox treatment for vaginismus". Plastic and Reconstructive Surgery. 124 (6): 455e–6e. doi:10.1097/PRS.0b013e3181bf7f11. PMID 19952618.
- Stavropoulos SN, Friedel D, Modayil R, Iqbal S, Grendell JH (March 2013). "Endoscopic approaches to treatment of achalasia". Therapeutic Advances in Gastroenterology. 6 (2): 115–35. doi:10.1177/1756283X12468039. PMC . PMID 23503707.
- Long H, Liao Z, Wang Y, Liao L, Lai W (February 2012). "Efficacy of botulinum toxins on bruxism: an evidence-based review". International Dental Journal. 62 (1): 1–5. doi:10.1111/j.1875-595X.2011.00085.x. PMID 22251031.
- Duthie J, Vincent M, Herbison GP, Wilson DI, Wilson D (2011). "Botulinum toxin injections for adults with overactive bladder syndrome". The Cochrane Database of Systematic Reviews. 7 (12): CD005493. doi:10.1002/14651858.CD005493.pub3. PMID 22161392.
- Mangera A, Andersson KE, Apostolidis A, Chapple C, Dasgupta P, Giannantoni A, Gravas S, Madersbacher S (October 2011). "Contemporary management of lower urinary tract disease with botulinum toxin A: a systematic review of botox (onabotulinumtoxinA) and dysport (abobotulinumtoxinA)". European Urology. 60 (4): 784–95. doi:10.1016/j.eururo.2011.07.001. PMID 21782318.
- Trzciński R, Dziki A, Tchórzewski M (2002). "Injections of botulinum A toxin for the treatment of anal fissures". The European Journal of Surgery = Acta Chirurgica. 168 (12): 720–3. doi:10.1080/11024150201680030. PMID 15362583.
- Kowal L, Wong E, Yahalom C (December 2007). "Botulinum toxin in the treatment of strabismus. A review of its use and effects". Disability and Rehabilitation. 29 (23): 1823–31. doi:10.1080/09638280701568189. PMID 18033607.
- Small R (2014). "Botulinum toxin injection for facial wrinkles". American Family Physician. 90 (3): 168–175. PMID 25077722.
- Eisenach JH, Atkinson JL, Fealey RD (May 2005). "Hyperhidrosis: evolving therapies for a well-established phenomenon". Mayo Clinic Proceedings. 80 (5): 657–66. doi:10.4065/80.5.657. PMID 15887434.
- Safarpour, Delaram; Mittal, Shivam; Jabbari, Bahman (2016). "Botulinum Toxin Treatment of Neuropathic Pain". Seminars in Neurology. 36: 073. doi:10.1055/s-0036-1571953.
- Charles PD (November 2004). "Botulinum neurotoxin serotype A: a clinical update on non-cosmetic uses". American Journal of Health-System Pharmacy. 61 (22 Suppl 6): S11–23. PMID 15598005.
- Coté TR, Mohan AK, Polder JA, Walton MK, Braun MM (September 2005). "Botulinum toxin type A injections: adverse events reported to the US Food and Drug Administration in therapeutic and cosmetic cases". Journal of the American Academy of Dermatology. 53 (3): 407–15. doi:10.1016/j.jaad.2005.06.011. PMID 16112345.
- "Information for Healthcare Professionals: OnabotulinumtoxinA (marketed as Botox/Botox Cosmetic), AbobotulinumtoxinA (marketed as Dysport) and RimabotulinumtoxinB (marketed as Myobloc)". fda.gov. Food and Drug Administration. Retrieved 1 September 2015.
- "Botox chemical may spread, Health Canada confirms". CBC News. January 13, 2009. Archived from the original on 21 February 2009.
- "Kinds of Botulism". Centers for Disease Control and Prevention. Retrieved 4 October 2016.
- "Botulism - Diagnosis and Treatment". Centers for Disease Control and Prevention. Retrieved 5 October 2016.
- Barr JR, Moura H, Boyer AE, Woolfitt AR, Kalb SR, Pavlopoulos A, McWilliams LG, Schmidt JG, Martinez RA, Ashley DL (October 2005). "Botulinum neurotoxin detection and differentiation by mass spectrometry". Emerging Infectious Diseases. 11 (10): 1578–83. doi:10.3201/eid1110.041279. PMC . PMID 16318699.
- Li B, Peet NP, Butler MM, Burnett JC, Moir DT, Bowlin TL (2011). "Small molecule inhibitors as countermeasures for botulinum neurotoxin intoxication". Molecules. 16 (1): 202–20. doi:10.3390/molecules16010202. PMID 21193845.
- Hill, Karen K; Smith, Theresa J (2013). "Genetic Diversity Within Clostridium botulinum Serotypes, Botulinum Neurotoxin Gene Clusters and Toxin Subtypes". In Rummel, Andreas; Binz, Thomas. Botulinum neurotoxins. Heidelberg: Springer. doi:10.1007/978-3-642-33570-9_1. ISBN 978-3-642-33569-3.
- Foran PG, Mohammed N, Lisk GO, Nagwaney S, Lawrence GW, Johnson E, Smith L, Aoki KR, Dolly JO (January 2003). "Evaluation of the therapeutic usefulness of botulinum neurotoxin B, C1, E, and F compared with the long lasting type A. Basis for distinct durations of inhibition of exocytosis in central neurons". The Journal of Biological Chemistry. 278 (2): 1363–71. doi:10.1074/jbc.M209821200. PMID 12381720.[non-primary source needed]
- Pellizzari R, Rossetto O, Schiavo G, Montecucco C (February 1999). "Tetanus and botulinum neurotoxins: mechanism of action and therapeutic uses". Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences. 354 (1381): 259–68. doi:10.1098/rstb.1999.0377. PMC . PMID 10212474.
- Kerner, J. (1820). Neue Beobachtungen über die in Württemberg so häufig vorfallenden tödlichen Vergiftungen durch den Genuss geräucherter Würste. Tübingen: Osiander.
- Kerner, J. (1822). Das Fettgift oder die Fettsäure und ihre Wirkungen auf den thierischen Organismus, ein Beytrag zur Untersuchung des in verdorbenen Würsten giftig wirkenden Stoffes. Stuttgart, Tübingen: Cotta.
- Erbguth FJ, Naumann M (November 1999). "Historical aspects of botulinum toxin: Justinus Kerner (1786-1862) and the "sausage poison"". Neurology. 53 (8): 1850–3. doi:10.1212/wnl.53.8.1850. PMID 10563638.
- van Ermengem E (February 1897). "Classics in infectious diseases. A new anaerobic bacillus and its relation to botulism. E. van Ermengem. Originally published as "Ueber einen neuen anaëroben Bacillus und seine Beziehungen zum Botulismus" in Zeitschrift für Hygiene und Infektionskrankheiten 26: 1-56, 1897". Reviews of Infectious Diseases (in German). 1 (4): 701–19. doi:10.1007/BF02220526. PMID 399378.
- Snipe, P. Tessmer; Sommer, H. (August 1928). "Studies on Botulinus Toxin: 3. Acid Precipitation of Botulinus Toxin". The Journal of Infectious Diseases. University of Chicago Press. 43 (2): 152–160. doi:10.1093/infdis/43.2.152. JSTOR 30083772.
- Lamanna C, McELROY OE, Eklund HW (May 1946). "The purification and crystallization of Clostridium botulinum type A toxin". Science. 103 (2681): 613. doi:10.1126/science.103.2681.613. PMID 21026141.
- Burgen AS, Dickens F, Zatman LJ (August 1949). "The action of botulinum toxin on the neuro-muscular junction". The Journal of Physiology. University of Chicago Press. 109 (1–2): 10–24. doi:10.1113/jphysiol.1949.sp004364. PMC . PMID 15394302.
- Magoon E, Cruciger M, Scott AB, Jampolsky A (May 1982). "Diagnostic injection of Xylocaine into extraocular muscles". Ophthalmology. 89 (5): 489–91. doi:10.1016/s0161-6420(82)34764-8. PMID 7099568.
- Drachman DB (August 1964). "Atrophy of skeletal muscle in chick embryos treated with botulinum toxin". Science. 145 (3633): 719–21. doi:10.1126/science.145.3633.719. PMID 14163805.
- Scott AB, Rosenbaum A, Collins CC (December 1973). "Pharmacologic weakening of extraocular muscles". Investigative Ophthalmology. 12 (12): 924–7. PMID 4203467.
- Scott AB (October 1980). "Botulinum toxin injection into extraocular muscles as an alternative to strabismus surgery". Ophthalmology. 87 (10): 1044–9. doi:10.1016/s0161-6420(80)35127-0. PMID 7243198.
- Scott AB (1994). "Change of eye muscle sarcomeres according to eye position". Journal of Pediatric Ophthalmology and Strabismus. 31 (2): 85–8. PMID 8014792.
- Tsui JK, Eisen A, Mak E, Carruthers J, Scott A, Calne DB (November 1985). "A pilot study on the use of botulinum toxin in spasmodic torticollis". The Canadian Journal of Neurological Sciences. Le Journal Canadien Des Sciences Neurologiques. 12 (4): 314–6. PMID 4084867.
- Koman LA, Mooney JF, Smith B, Goodman A, Mulvaney T (1993-08-01). "Management of cerebral palsy with botulinum-A toxin: preliminary investigation". Journal of Pediatric Orthopedics. 13 (4): 489–95. doi:10.1097/01241398-199307000-00013. PMID 8370782.
- Pasricha PJ, Ravich WJ, Kalloo AN (January 1993). "Botulinum toxin for achalasia". Lancet. 341 (8839): 244–5. doi:10.1016/0140-6736(93)90109-T. PMID 8093528.
- UK Approves New Botox Use. dddmag.com. February 4, 2014
- Ocampo Vicente Victor D, Jr.; Foster, C Stephen (May 30, 2012). "Infantile Esotropia Treatment & Management". Medscape. Retrieved April 6, 2014.
- Boffey, Philip M. (October 14, 1986). "Loss Of Drug Relegates Many To Blindness Again". The New York Times. Retrieved July 14, 2010.
- Clark RP, Berris CE (August 1989). "Botulinum toxin: a treatment for facial asymmetry caused by facial nerve paralysis". Plastic and Reconstructive Surgery. 84 (2): 353–5. doi:10.1097/01.prs.0000205566.47797.8d. PMID 2748749.
- Carruthers JD, Carruthers JA (January 1992). "Treatment of glabellar frown lines with C. botulinum-A exotoxin". The Journal of Dermatologic Surgery and Oncology. 18 (1): 17–21. doi:10.1111/j.1524-4725.1992.tb03295.x. PMID 1740562.
- Keen M, Kopelman JE, Aviv JE, Binder W, Brin M, Blitzer A (April 1994). "Botulinum toxin A: a novel method to remove periorbital wrinkles". Facial Plastic Surgery. Thieme Medical Publishers. 10 (2): 141–6. doi:10.1055/s-2008-1064563. PMID 7995530.
- "Botulinum Toxin Type A Product Approval Information – Licensing Action 4/12/02". Food and Drug Administration. October 29, 2009. Retrieved July 26, 2010.
- "Allergan Receives FDA Approval for First-of-Its-Kind, Fully in vitro, Cell-Based Assay for BOTOX® and BOTOX® Cosmetic (onabotulinumtoxinA)". Allergan, Inc. News Provided by Acquire Media. June 24, 2011. Retrieved June 26, 2011.
- "In U.S., Few Alternatives To Testing On Animals". Washington Post. April 12, 2008. Retrieved June 26, 2011.
- Binder WJ, Brin MF, Blitzer A, Schoenrock LD, Pogoda JM (December 2000). "Botulinum toxin type A (BOTOX) for treatment of migraine headaches: an open-label study". Otolaryngology--Head and Neck Surgery. 123 (6): 669–76. doi:10.1067/mhn.2000.110960. PMID 11112955.
- Jackson JL, Kuriyama A, Hayashino Y (April 2012). "Botulinum toxin A for prophylactic treatment of migraine and tension headaches in adults: a meta-analysis". Jama. 307 (16): 1736–45. doi:10.1001/jama.2012.505. PMID 22535858.
- Ramachandran R, Yaksh TL (September 2014). "Therapeutic use of botulinum toxin in migraine: mechanisms of action". British Journal of Pharmacology. 171 (18): 4177–92. doi:10.1111/bph.12763. PMC . PMID 24819339.
- Chapman, Paul (May 10, 2012). "The global botox market forecast to reach $2.9 billion by 2018". Retrieved October 5, 2012.
- Koirala, Janak; Basnet, Sangita (July 14, 2004). "Botulism, Botulinum Toxin, and Bioterrorism: Review and Update". Medscape. Cliggott Publishing. Retrieved July 14, 2010.
- Clostridium botulinum – Public Health Agency of Canada. Phac-aspc.gc.ca (April 19, 2011). Retrieved on May 6, 2012.
- Baselt RC (2014). Disposition of toxic drugs and chemicals in man. Seal Beach, Ca.: Biomedical Publications. pp. 260–261. ISBN 978-0-9626523-9-4.
- "2011 Allergan Annual Report" (PDF). Allergan. Retrieved May 3, 2012. See PDF page 7.
- Walker TJ, Dayan SH (February 2014). "Comparison and overview of currently available neurotoxins". The Journal of Clinical and Aesthetic Dermatology. 7 (2): 31–9. PMC . PMID 24587850.
- "Botulinum Toxin Type A". Hugh Source (International) Limited. Retrieved July 14, 2010.
- Petrou, Ilya (Spring 2009). "Medy-Tox Introduces Neuronox to the Botulinum Toxin Arena" (PDF). The European Aesthetic Guide.
- Schantz EJ, Johnson EA (March 1992). "Properties and use of botulinum toxin and other microbial neurotoxins in medicine". Microbiological Reviews. 56 (1): 80–99. PMC . PMID 1579114.
- CDC – Botulism, General Information – NCZVED. Cdc.gov. Retrieved on May 6, 2012.
- Licciardello JJ, Nickerson JT, Ribich CA, Goldblith SA (March 1967). "Thermal inactivation of type E botulinum toxin". Applied Microbiology. 15 (2): 249–56. PMC . PMID 5339838.
- Setlow P (April 2007). "I will survive: DNA protection in bacterial spores". Trends in Microbiology. 15 (4): 172–80. doi:10.1016/j.tim.2007.02.004. PMID 17336071.
- Jay, James M.; Loessner, Martin J.; Golden, David A. (2005). "Chapter 24: Food Poisoning Caused by Gram-Positive Sporeforming Bacteria". Modern Food Microbiology: Seventh Edition. New York: Springer. p. 581. ISBN 0-387-23180-3.
- Capková K, Salzameda NT, Janda KD (October 2009). "Investigations into small molecule non-peptidic inhibitors of the botulinum neurotoxins". Toxicon. 54 (5): 575–82. doi:10.1016/j.toxicon.2009.03.016. PMC . PMID 19327377.
- Flanders M, Tischler A, Wise J, Williams F, Beneish R, Auger N (June 1987). "Injection of type A botulinum toxin into extraocular muscles for correction of strabismus". Canadian Journal of Ophthalmology. Journal Canadien d'Ophtalmologie. 22 (4): 212–7. PMID 3607594.
- Scott AB (September 1989). "Botulinum toxin therapy of eye muscle disorders. Safety and effectiveness. American Academy of Ophthalmology". Ophthalmology. American Academy of Ophthalmology. Suppl: 37–41. PMID 2779991.
- United States Department of Health and Human Services (April 30, 2009). "Re: Docket No. FDA-2008-P-0061" (PDF, 8.2 MB). Food and Drug Administration. Retrieved July 26, 2010.
- Giesler, Markus (2012). "How Doppelgänger Brand Images Influence the Market Creation Process: Longitudinal Insights from the Rise of Botox Cosmetic". Journal of Markeing. 76 (6): 55–68. doi:10.1509/jm.10.0406.
- "BOTOX® Cosmetic (onabotulinumtoxinA) Product Information". Allergan, Inc. January 22, 2014. Retrieved January 22, 2014.
- Bushara KO, Park DM (November 1994). "Botulinum toxin and sweating". Journal of Neurology, Neurosurgery, and Psychiatry. 57 (11): 1437–8. doi:10.1136/jnnp.57.11.1437. PMC . PMID 7964832.
- Walsh, Sandy (October 15, 2010). "FDA approves Botox to treat chronic migraine". FDA Press Releases. Retrieved October 15, 2010.
- Watkins, Tom (October 15, 2010). "FDA approves Botox as migraine preventative". CNN (US).
- Dodick DW, Turkel CC, DeGryse RE, Aurora SK, Silberstein SD, Lipton RB, Diener HC, Brin MF, PREEMPT Chronic Migraine Study Group (June 2010). "OnabotulinumtoxinA for treatment of chronic migraine: pooled results from the double-blind, randomized, placebo-controlled phases of the PREEMPT clinical program". Headache. 50 (6): 921–36. doi:10.1111/j.1526-4610.2010.01678.x. PMID 20487038.
- Ashkenazi A (March 2010). "Botulinum toxin type a for chronic migraine". Current Neurology and Neuroscience Reports. 10 (2): 140–6. doi:10.1007/s11910-010-0087-5. PMID 20425239.