Hydrocodone

Hydrocodone is a semi-synthetic opioid derived from codeine, used medically for moderate-to-severe pain and, in some formulations, to suppress cough. It is most familiar in combination products that pair it with acetaminophen, sold under brand names such as Vicodin and Norco, and in extended-release single-ingredient formulations. As a prescription opioid it is effective for pain but carries the addiction, overdose and dependence risks common to the opioid class, and it has been a significant contributor to the US opioid epidemic.

Hydrocodone is an agonist at mu-opioid receptors in the brain, spinal cord and elsewhere. Activating these receptors reduces the perception of pain and can produce euphoria and drowsiness, but it also suppresses the brainstem centers that drive breathing. This respiratory-depressant effect is the mechanism behind fatal opioid overdose. Repeated activation of opioid receptors leads to tolerance, needing more for the same effect, and to physical dependence, so that stopping produces withdrawal.

Effects include pain relief, relaxation, drowsiness and for some a sense of euphoria, along with common opioid side effects such as constipation, nausea, itching and pupil constriction. Higher exposures cause pronounced sedation, slowed and shallow breathing, confusion and loss of consciousness. Combination products carry an added danger: the acetaminophen they contain can cause severe, potentially fatal liver injury if intake is high, a risk that is easy to overlook.

The defining acute danger of hydrocodone, like all opioids, is respiratory depression: breathing slows and can stop, which is how opioid overdoses kill. This risk rises sharply when hydrocodone is combined with other central nervous system depressants such as alcohol, benzodiazepines or other sedatives, because their effects on breathing stack; opioid-plus-depressant combinations are among the deadliest. Tolerance and physical dependence develop with regular use, and a period of abstinence after detox, incarceration or a break sharply lowers tolerance, so a previously routine amount can become fatal. Opioid withdrawal is intensely unpleasant but not usually life-threatening on its own. A critical contamination hazard applies to any opioid obtained outside a pharmacy: the illicit pill supply is widely adulterated with illicitly manufactured fentanyl, and counterfeit tablets pressed to look like genuine hydrocodone or other pharmaceuticals have caused many deaths in people who did not know they were taking fentanyl. Naloxone, sold as Narcan, can reverse an opioid overdose and is increasingly available without a prescription; because fentanyl is so potent, more than one dose may be needed. If someone is unresponsive or breathing slowly, call 911 and give naloxone if available. This page has not yet been medically reviewed.