|This article needs additional citations for verification. (December 2009)|
Insufflation (Latin insufflatio "blowing on" or "into") is the act of inhaling something (such as a gas, powder, or vapor) into a body cavity. Insufflation has medical use as a route of administration for many respiratory drugs used to treat conditions in the lungs (e.g., asthma or emphysema) and paranasal sinus (e.g., allergy).
The technique is common for many recreational drugs and is also used for some entheogens. Nasal insufflation (snorting) is commonly used for many psychoactive drugs because it causes a much faster onset than orally, and bioavailability is usually, but not always, higher than orally. This bioavailability occurs due to the quick absorption of molecules into the bloodstream through the soft tissue in the mucous membrane of the sinus cavity and portal circulation bypass. Some drugs have a higher rate of absorption, and are thus more effective in smaller doses, through this route. Prodrugs, drugs that are metabolized or activated by the liver (such as codeine), should not be insufflated, because they need to be metabolized by the liver to break down into the compounds that are active (drugs absorbed through the GI tract pass through the liver before entering the systemic circulation, where drugs which are insufflated are absorbed directly into the systemic circulation).
Nasal administration (administration through the nose) may allow certain drugs and other molecules to bypass the blood–brain barrier via diffusion through the olfactory epithelium and the perineural sheath or via retrograde axonal transport along olfactory and trigeminal nerves. This latter process probably implies endocytosis of the molecules. Using this route to the brain allows high concentrations of products in the olfactory bulb shortly after exposition and by diffusion to the entire brain. Therefore using this pathway allows a better bioavailability, assuming that the molecule has the right physico-chemical characteristics to get through the nose and the epithelial defences.
Nasal administration – a more general term than insufflation – of various lipid-soluble medications is increasing in popularity. It is often used for treatment of children or patients who are otherwise alarmed or frightened by needles, or where intravenous (IV) access is unavailable. The time of onset for drugs delivered via nasal administration is generally only marginally slower than if given via IV. In addition to a variety of nasal sprays readily available from pharmacies, some common medications delivered via nasal administration include fentanyl, midazolam and naloxone. Nasal sprays are not insufflated as they are, by definition, sprayed, not blown, into the nose.
Psychoactive substances are often insufflated nasally for the purpose of nasal absorption through the mucous membrane, which is often more rapid, or more complete, than gastrointestinal absorption. For a substance to be effective when insufflated, it must be water-soluble so it can be absorbed into the mucous membranes. The verb "snort" is synonymous with insufflate in this context, as are several slang words.
Although the majority of a dose of insufflated drug is taken up through the mucous membranes, some enters other parts of the gastrointestinal tract where it may also be absorbed. This is because some of the dose drips down the throat and into the stomach.
Commonly insufflated psychoactive substances (for non-medical use) include:
- Cocaine (benzoylmethylecgonine) - a stimulant and analgesic that is most commonly associated with drug insufflation
- Opioids - a class of drugs (including heroin, morphine, oxycodone, buprenorphine, hydromorphone, oxymorphone and the synthetic meperidine and fentanyl).
- Amphetamines - another class of stimulants (including amphetamine, dextroamphetamine and methamphetamine)
- Methylphenidate - another stimulant
- Ketamine - a dissociative anaesthetic
- Phencyclidine - a dissociative anaesthetic, commonly known as PCP or angel dust
- MDMA/Ecstasy - an entactogen that also possesses stimulant effects
- Zolpidem (Ambien) - a sedative hypnotic
- Tobacco snuff - a stimulant that contains nicotine
Many recreational drugs which are commonly insufflated, such as cocaine, can cause damage to the nasal cavity, and have even been known to destroy the nasal septum. Any damage to the inside of the nose is either because some insufflation highly constricts blood vessels – and therefore blood and oxygen/nutrient flow – to that area, or because the substance is physically corrosive. A famous case where the septum was completely destroyed by cocaine was of EastEnders star Danniella Westbrook.
- William H. Frey. "Bypassing the Blood-Brain Barrier to Deliver Therapeutic Agents to the Brain and Spinal Cord." Drug Delivery Technology.
- Lawrence, Ghislaine (20 April 2002). "Tobacco smoke enemas". The Lancet 359 (9315): 1442. http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(02)08339-3/fulltext. Retrieved 2008-11-27.
- Born J, Lange T, Kern W, McGregor GP, Bickel U, Fehm HL. (2002). Sniffing neuropeptides: a transnasal approach to the human brain. Nat Neurosci.5(6):514-6. doi:10.1038/nn849 PMID 11992114
- Westbrook, Danniella (2006). The Other Side of Nowhere. Hodder. ISBN 0-340-89887-9.
- Aaron S, McMahon JM, Milano D, Torres L, Clatts M, Tortu S, Mildvan D, Simm M. (2008). "Intranasal Transmission of Hepatitis C Virus: Virological and Clinical Evidence". Clinical Infectious Diseases 47 (7): 931–934. doi:10.1086/591699.