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Combination of
Hydrocodone Opioid analgesic
Paracetamol Anilide analgesic
Clinical data
Trade names Hycet, Lorcet, Lorcet Plus, Lortab, Maxidone, Norco, Vicodin, Vicodin ES, Vicodin HP, Zamicet, and Zydone (possibly others)
AHFS/Drugs.com entry
  • US: C (Risk not ruled out)
Legal status
Routes of
ATC code N02AA08-
PubChem CID: 11247932
ChemSpider 9422965 YesY
 YesY (what is this?)  (verify)

Hydrocodone/paracetamol, hydrocodone/acetaminophen, or hydrocodone/APAP (marketed under trade names such as Lortab, Norco and Vicodin) is a combination opioid narcotic and analgesic drug consisting of hydrocodone and paracetamol (also known as acetaminophen) used to relieve moderate to severe pain.[1] It exists in tablet, elixir and solution in various strengths for oral administration.[1]



Hydrocodone/acetaminophen is a two-ingredient combination formula consisting of the opioid hydrocodone and the non-opioid analgesic acetaminophen. It is indicated for relief of moderate to severe pain of acute, chronic or postoperative types.[2] Hydrocodone/acetaminophen comes in oral solution and tablet formulations; however strength of each component may vary.[3] In October 2014, the Drug Enforcement Administration rescheduled hydrocodone combination drugs from schedule III to schedule II due to its risk for misuse, abuse, and diversions.[4]


For more details on this topic, see Hydrocodone § Recreational use.

Hydrocodone diversion and recreational use has escalated in recent years due to its opioid effects.[5] In 2009 and 2010, hydrocodone was the second-most frequently encountered opioid pharmaceutical in drug evidence submitted to U.S. federal, state, and local forensic laboratories as reported by DEA’s National Forensic Laboratory Information System (NFLIS) and System to Retrieve Information from Drug Evidence (STRIDE).[6]

Special population[edit]

Pregnancy and breastfeeding[edit]

Pregnancy category C: Risk in pregnancy cannot be ruled out. Animal controlled studies have not been conducted with this medication.[7]

Low concentrations of acetaminophen is excreted through breast milk, however, hydrocodone's excretion is unknown.[7]

Kidney and liver impairment[edit]

Use with caution (due to possible risk of toxicity)[7]

Side effects[edit]

Most common[edit]

  • Lightheadedness [2]
  • Dizziness [2]
  • Euphoria [2]
  • Sedation [2]
  • Nausea, and vomiting [2]

Less common[edit]

  • Central Nervous System: drowsiness, confusion, lethargy, anxiety, fear, unease, psychic dependence, mood changes, impairment of mental and physical performance[2]
  • Gastrointestinal System: constipation [2]
  • Genitourinary System: inability to urinate, bladder spasms [2]
  • Respiratory Depression: inadequate breaths [2]
  • Special Senses: hearing impairment, permanent hearing loss [2]
  • Dermatological: rash, itching [2]

* Exact prevalence (%) is unknown

Black box warning[edit]

"Acetaminophen has been associated with cases of acute liver failure, at times resulting in liver transplant and death. Most of the cases of liver injury are associated with the use of acetaminophen at doses that exceed 4000 milligrams per day, and often involve more than one acetaminophen-containing product." [2]

Allergy warning[edit]

"Do not take hydrocodone bitartrate and acetaminophen tablets if you are allergic to any of its ingredients. If you develop signs of allergy such as a rash or difficulty breathing stop taking hydrocodone bitartrate and acetaminophen tablets and contact your healthcare provider immediately."[2]


Hydrocodone: Respiratory depression, extreme somnolence progressing towards coma, muscle limpness, cold and clammy skin, slow heart rate, low blood pressure, abrupt loss of heart function and death may occur.[2]

Acetaminophen: Liver and kidney failure, low blood sugar coma may occur.[2]


Hydrocodone/acetaminophen may demonstrate an enhanced respiratory depressant effect when combined with other sedatives such as other opioids, benzodiazepines, nonbenzodiazepines sedatives, psychotropics, anticonvulsants.[8]

Concurrent use with alcohol products may increase the risk of acute liver failure.[2]


Laboratory function tests should be used to monitor therapy in patients with severe liver or renal disease.[2]



  • Mechanism of Action: Hydrocodone acts primarily at the mu-opioid receptors, but is also a weak agonist against the delta opioid and kappa opioid receptors.[9]
  • Absorption/ Distribution: The oral formulation can be absorbed from the gastrointestinal track and remain 20-50% bound to plasma proteins.[9] The onset of analgesia is about 20 to 30 minutes with duration of 4 to 8 hours and t1/2 of 3 to 4 hours.[9]
  • Metabolism/ Excretion: It is metabolized to norhydrocodone by cytochrome P450 3A4 and to hydromorphone, also biologically active, by cytochrome P450 2D6.[10][11] For individuals who have a defect in the gene encoding CYP2D6, the clearance of the drug will be lower and less metabolite such as hydromorphone will be formed; however, the effect on analgesia remains unknown.[11]


  • Mechanism of Action: Acetaminophen acts to inhibit COX enzyme, which is responsible for prostaglandin synthesis.[12] Prostaglandins increase the perception of pain. Inhibition of prostaglandin production helps to alleviate pain.[13]
  • Absorption/ Distribution: The half-life of oral acetaminophen is 1.25 to 3 hours and peak level is reached by 10–60 minutes after ingestion.[14]
  • Metabolism/ Excretion: Acetaminophen is metabolized primarily in the liver via glucuronidation and sulfation to mostly non-toxic metabolites and some highly reactive metabolites, which is inactivated by glutathione.[14] 85% of the oral dose is excreted renally.[2] At high doses, the supply of glutathione cannot meet its demand, thus results in the accumulation of highly reactive compounds leading to liver damage.[14]


On June 30, 2009, a U.S. Food and Drug Administration (FDA) advisory panel voted by a narrow margin to advise the FDA to remove Vicodin and another opioid, Percocet, from the market because of "a high likelihood of overdose from prescription narcotics and acetaminophen products".[15] The panel also cited concerns of liver damage from their acetaminophen component, which is also the main ingredient in commonly used nonprescription drugs such as Tylenol.[15] Each year, acetaminophen overdose is linked to about 400 deaths and 42,000 hospitalizations.[16]

In January 2011, the FDA asked manufacturers of prescription combination products that contain acetaminophen to limit the amount of acetaminophen to no more than 325 mg in each tablet or capsule within 3 years.[17][18][19][20] The FDA also required manufacturers on all acetaminophen containing products to issue a black box warning indicating the potential risk for severe liver injury and a warning highlighting potential for allergic reactions.[17][18][20]

On August 22, 2014, the Drug Enforcement Administration (DEA) announced that all hydrocodone combination products (HCPs) will be rescheduled from Schedule III to Schedule II of the Controlled Substances Act (CSA), effective on October 6, 2014.[21] In 2010, more than 16,000 deaths were attributed to abuse of opioid drugs.[21] Even though there are legitimate medical uses for HCPs, data suggest that a significant number of individuals misuse HCPs.[21]

See also[edit]


  1. ^ a b Lortab [package insert]. Richmond, VA: ECR Pharmaceuticals, Inc: 2014.
  2. ^ a b c d e f g h i j k l m n o p q r s "Vicodin Generic Prescribing Information". www.vicodin.com. Retrieved 2015-11-04. 
  3. ^ "Acetaminophen / Hydrocodone Dosage Guide with Precautions - Drugs.com". www.drugs.com. Retrieved 2015-11-04. 
  4. ^ "Rules - 2014 - Rescheduling of Hydrocodone Combination Products From Schedule III to Schedule II". www.deadiversion.usdoj.gov. Retrieved 2015-11-04. 
  5. ^ "Norco Addiction | The Fix". The Fix. Retrieved 2015-11-04. 
  6. ^ "Hydrocodone (Trade Names: Vicodin, Lortab, Lorcet-HD, Hycodan, Vicoprofen)" (PDF). US DOJ - DEA. April 2013. Retrieved 21 May 2013. 
  7. ^ a b c "Norco - FDA prescribing information, side effects and uses". www.drugs.com. Retrieved 2015-11-04. 
  8. ^ Becker, Daniel E. (2011-01-01). "Adverse Drug Interactions". Anesthesia Progress 58 (1): 31–41. doi:10.2344/0003-3006-58.1.31. ISSN 0003-3006. PMC 3265267. PMID 21410363. 
  9. ^ a b c Vallejo, Ricardo; Barkin, Robert L.; Wang, Victor C. (2011-08-01). "Pharmacology of opioids in the treatment of chronic pain syndromes". Pain Physician 14 (4): E343–360. ISSN 2150-1149. PMID 21785485. 
  10. ^ Cone, E. J.; Darwin, W. D.; Gorodetzky, C. W.; Tan, T. (1978-08-01). "Comparative metabolism of hydrocodone in man, rat, guinea pig, rabbit, and dog". Drug Metabolism and Disposition: The Biological Fate of Chemicals 6 (4): 488–493. ISSN 0090-9556. PMID 28931. 
  11. ^ a b Kaye, Alan David (2015). Essentials of Pharmacology for Anesthesia, Pain Medicine, and Critical Care. Springer. pp. 134–13. ISBN 9781461489481. 
  12. ^ Graham, Garry G.; Scott, Kieran F. (2005-02-01). "Mechanism of action of paracetamol". American Journal of Therapeutics 12 (1): 46–55. ISSN 1075-2765. PMID 15662292. 
  13. ^ Golan, David E. (2008). Principles of Pharmacology: The Pathophysiologic Basis of Drug Therapy. Lippincott Williams & Wilkins. pp. 275–276. ISBN 978-0-7817-8355-2. 
  14. ^ a b c Sinatra, Raymond S. (2011). The Essence of Analgesia and Analgesics. Cambridge University Press. p. 256. ISBN 978-0-521-14450-6. 
  15. ^ a b "FDA advisers vote to take Vicodin, Percocet off market". cnn.com. 
  16. ^ Harris, Gardiner (2011-01-13). "F.D.A. Plans New Limits on Prescription Painkillers". The New York Times. ISSN 0362-4331. Retrieved 2015-11-04. 
  17. ^ a b "FDA limits acetaminophen in prescription combination products; requires liver toxicity warnings" (Press release). U.S. Food and Drug Administration. January 13, 2011. Retrieved January 13, 2011. 
  18. ^ a b "FDA Drug Safety Communication: Prescription Acetaminophen Products to be Limited to 325 mg Per Dosage Unit; Boxed Warning Will Highlight Potential for Severe Liver Failure". U.S. Food and Drug Administration (FDA). January 13, 2011. Retrieved January 13, 2011. 
  19. ^ Matthew Perrone (January 13, 2011). "FDA orders lowering pain reliever in Vicodin". The Boston Globe. Associated Press. Retrieved January 13, 2011. 
  20. ^ a b Gardiner Harris (January 13, 2011). "F.D.A. Plans New Limits on Prescription Painkillers". The New York Times. Retrieved January 13, 2011. 
  21. ^ a b c "Federal Register - Schedules of Controlled Substances: Rescheduling of Hydrocodone Combination Products From Schedule III to Schedule II". usa.gov. 

External links[edit]