Hydrocodone/paracetamol

Hydrocodone/paracetamol is a fixed-dose combination consisting of the opioid hydrocodone and the non-opioid analgesic paracetamol. It is indicated for relief of moderate to severe pain of acute, chronic, or postoperative types.[10] Hydrocodone/paracetamol comes in oral solution and tablet formulations; however strength of each component may vary.[11] 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.[12]

Hydrocodone diversion and recreational use has escalated in recent years due to its opioid effects.[13] 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).[14]

Pregnancy category C: Risk in pregnancy cannot be ruled out. Animal controlled studies have not been conducted with this medication.[15]

Low concentrations of paracetamol is excreted through breast milk, however, hydrocodone's excretion is unknown.[15]

Use with caution due to possible risk of toxicity.[15]

• Lightheadedness[10]
• Dizziness[10]
• Euphoria
• Sedation[10]
• Nausea and vomiting[10]
• Headaches

• Central nervous system: drowsiness, confusion, lethargy, anxiety, fear, unease, dependence, mood changes, impairment of mental and physical performance[10]
• Gastrointestinal system: constipation[10]
• Genitourinary system: inability to urinate, bladder spasms[10]
• Respiratory depression: decreased rate and effort of breathing[10]
• Hearing impairment, permanent hearing loss[10]
• Dermatological: rash, itching[10]

"Paracetamol has been associated with cases of acute liver failure, at times resulting in liver transplant or death. Most of the cases of liver injury are associated with the use of paracetamol at doses that exceed 4000 milligrams per day, and often involve more than one paracetamol-containing product."[10]

"Do not take hydrocodone bitartrate and paracetamol 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 paracetamol tablets and contact your healthcare provider immediately."[10]

• Mechanism of action: Hydrocodone acts primarily as an agonist at the mu-opioid receptors, but is also a weak agonist against the delta opioid and kappa opioid receptors.[17]
• Absorption/distribution: The oral formulation can be absorbed from the gastrointestinal tract and remain 20–50% bound to plasma proteins.[17] The onset of analgesia is about 20 to 30 minutes with duration of 4 to 8 hours and t_1/2 of 3 to 4 hours.[17]
• Metabolism/excretion: It is metabolized to norhydrocodone by cytochrome P450 3A4 and to hydromorphone, also biologically active, by cytochrome P450 2D6.[18][19] 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.[19]

• Mechanism of action: Paracetamol acts to inhibit COX enzyme, which is responsible for prostaglandin synthesis.[5] Prostaglandins increase the perception of pain. Inhibition of prostaglandin production helps to alleviate pain.[20]
• Absorption/distribution: The half-life of oral paracetamol is 1.25 to 3 hours and peak level is reached by 10–60 minutes after ingestion.[21]
• Metabolism/excretion: Paracetamol 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.[21] 85% of the oral dose is excreted renally.[10] At high doses, the supply of glutathione cannot meet its demand, thus results in the accumulation of highly reactive compounds leading to liver damage.[21]

On 30 June 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".[24] The panel also cited concerns of liver damage from their paracetamol component, which is also the main ingredient in commonly used nonprescription drugs such as Tylenol.[24] Each year, paracetamol overdose is linked to about 400 deaths and 42,000 hospitalizations.[25]

In January 2011, the FDA asked manufacturers of prescription combination products that contain paracetamol to limit the amount of paracetamol to no more than 325 mg in each tablet or capsule within three years.[26][27][28][29] The FDA also required manufacturers on all paracetamol containing products to issue a black box warning indicating the potential risk for severe liver injury and a warning highlighting potential for allergic reactions.[26][27][29]

On 22 August 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 6 October 2014.[30] In 2010, more than 16,000 deaths were attributed to abuse of opioid drugs.[30] Even though there are legitimate medical uses for HCPs, data suggest that a significant number of individuals misuse them.[30]

Vicodin is mentioned in songs such as Juice Wrld's "Already Dead" Eminem's "Kill You", Blackbear's "Sniffing Vicodin in Paris", Kendrick Lamar's "A.D.H.D", Future's "Lay Up", Lupe Fiasco's "Mural", Queens of the Stone Age's "Feel Good Hit of the Summer", A Winged Victory for the Sullen's "Steep Hills of Vicodin Tears", Death Grips's "Anne Bonny" and The Wombats' "Give Me a Try". Vicodin use is a central theme in the 2004–2012 medical TV drama House, in which the lead character Dr. Gregory House is addicted to the drug combination.

Brand names include Adol, Hycet, Lortab, Lorcet, Norco, and Vicodin among others.[31]