DESCRIPTION / DEFINITIONS: Norco® (hydrocodone bitartrate and acetaminophen).

ABUSE: Norco® contains hydrocodone which is an opioid agonist and a Schedule II controlled substance.

ADDICTION / DEPENDENCE: Half life and metabolism.

SIDE EFFECTS: Respiratory depression, opioid-induced hyperalgesia (see list below).

WITHDRAWAL SYMPTOMS: Nausea, vomiting, diarrhea (see list below).

TREATMENT: Medical detoxification.



Norco® (hydrocodone bitartrate and acetaminophen)

Norco tablets are narcotic pain killers for the relief of moderate to moderately severe pain. According to its label, “Hydrocodone is a semi-synthetic narcotic analgesic and antitussive with multiple actions qualitatively similar to those of codeine. The precise mechanism of action of hydrocodone and other opiates is not known, although it is believed to relate to the existence of opiate receptors in the central nervous system.”

Acetaminophen is an analgesic used to relieve mild to moderate pain from headaches, muscle aches, menstrual periods, colds and sore throats, toothaches, backaches, and reactions to vaccinations (shots), and acts as an antipyretic to reduce fever. Acetaminophen is the active ingredient in Tylenol.  The label states, “The analgesic action of acetaminophen involves peripheral influences, but the specific mechanism is as yet undetermined.”

According to the DEA, a Schedule II narcotic means that:

(A) The drug or other substance has a high potential for abuse.

(B) The drug or other substance has a currently accepted medical use in treatment in the United States or a currently accepted medical use with severe restrictions.

(C) Abuse of the drug or other substances may lead to severe psychological or physical dependence.

The Encarta Dictionary defines:

  • therapeutic as “Used in treating disease”
  • narcotic as, “A typically addictive drug, especially one derived from opium, that may produce effects ranging from pain relief and sleep to stupor, coma, and convulsions”
  • analgesic as, “A type of medication that alleviates pain without loss of consciousness.” It is interesting to point out that the word analgesia is derived from the Greek “an” meaning without and “algesis” meaning sense of pain. Analgesic drugs are intended to take away the sense of pain but not to address the cause of the pain.

  • antitussive as, “A drug that controls coughing.”
  • antipyretic as, “A drug or other agent that reduces fever.” from the Greek pyresis, which means fire.
  • an “agonist” is something that stimulates or produces an effect. Agonist is derived from the Late Latin agnista which means contender, which is derived from the Greek agonists which also means contestant which came from agonmeaning contest.


The drug label warns, “Norco, and other opioids used in analgesia can be abused and are subject to criminal diversion.”



Norco® contains hydrocodone which is an opioid agonist and a Schedule II controlled substance.





The biological half life of a substance is the time it takes for a drug to lose half of its pharmacologic activity. This is significant because it affects how soon withdrawal symptoms may appear.

The half life of the hydrocodone in Norco is 3.8 hours and the half-life of the acetaminophen in Norco is 1.3 hours to 3 hours.

It has not been determined how the hydrocodone in Norco is metabolized.  Most scientists have stated that it is through the P450 pathway in the liver and the enzyme primarily handling the metabolism is the CYP2D6 enzyme.  Other scientists believe that it is metabolized by the UGT enzymes.

The acetaminophen in Norco is believed to be primarily metabolized through the P450 pathway in the liver and the enzymes 2E1 and 1A2.

The CYP enzymes are the major enzymes involved in drug metabolism, and since many drugs may increase or decrease the activity of various CYP isozymes, this is a major source of adverse drug interactions, since changes in CYP enzyme activity may affect the metabolism and clearance of various drugs. For example, if one drug inhibits the CYP-mediated metabolism of another drug, the second drug may accumulate within the body to toxic levels, possibly causing an overdose.



The following adverse experiences were reported in Norco®-treated patients:

  • Agranulocytosis (increased white blood cells and lesions)
  • Allergic reactions
  • Anxiety
  • Apnea
  • Bradycardia (slowed heart rate)
  • Cardiac arrest
  • Circulatory collapse
  • Cold and clammy skin
  • Constipation
  • Death
  • Diaphoresis (sweating)
  • Dizziness
  • Drowsiness
  • Dysphoria (feeling of hopelessness)
  • Extreme somnolence progressing to stupor or coma
  • Fear
  • General malaise
  • Hearing impairment or permanent loss
  • Hypotension (low blood pressure)
  • Impairment of mental and physical performance
  • Lethargy
  • Lightheadedness
  • Mental clouding
  • Mood changes
  • Nausea
  • Pruritus (Itchiness)
  • Psychic dependence
  • Respiratory depression
  • Sedation
  • Skeletal muscle flaccidity
  • Skin rash
  • Somnolence
  • Spasm of vesical sphincters
  • Thrombocytopenia (low blood platelets)
  • Ureteral spasm
  • Urinary retention
  • Vomiting



There is increasing medical research showing that taking opioids like OxyContin for longer than six months will create a condition called Opioid Induced Hyperalgesia. This is a condition where the opioids actually make the pain receptors more sensitive and, therefore, the pain greater. A person with this condition is required to take more and more of the opioid to try to address the pain but finds that the pain actually increases.



Norco is a highly addictive drug. Users of Norco for a time are likely to become either dependent on or addicted to the drug. If someone is dependent on a drug they will experience withdrawal symptoms. They normally continue taking the drug because they don’t want to experience withdrawal symptoms. Here are some of the Norco withdrawal symptoms:

  • Abdominal pain
  • Chills, fever
  • Craving for the drug
  • Dilated pupils
  • Dysphoria (anxious, depressed or uneasy mental state)
  • Flushing
  • Irritability
  • Loss of appetite
  • Mild to moderate sleep disturbances
  • Muscle spasms, especially in the lower extremities
  • Nausea, vomiting, diarrhea
  • Piloerection (erection of the hair of the skin)
  • Running nose
  • Severe insomnia
  • Spontaneous ejaculation
  • Sweating
  • Tearing
  • Tremors
  • Violent yawning
  • Weakness
  • Yawning


It is estimated that over 95% of the people who attempt to withdraw from Norco or other similar opioids or opiates on their own will not succeed because of the pain of the withdrawal. Medical detox facilities are available that use buprenorphine to assist in the withdrawal and make it much less uncomfortable and safe. Call us to talk to a Novus Detox Advisor.