Hydrocodone is a semi synthetic opioid (narcotic) derived from two of the naturally occurring opiates, codeine and thebaine. Hydrocodone is prescribed for the relief of moderate to moderately severe pain. It is taken orally as an active narcotic analgesic (pain killer) and an antitussive (cough suppressant). The pain relief by hydrocodone is thought to involve peripheral and central actions but the exact mechanism(s) remains unknown.
Due to hydrocodone being a drug that acts on the brain, its major side effects are central and include:
Over the last 2 decades, sales and consumption of this drug have increased significantly. Even though the drug can only be prescribed by physicians, hydrocodone is relatively easily available over internet pharmacies without a need of a prescription. Besides being used as an efficient pain killer, its illicit use has also increased significantly. The drug is available in various forms including tablet, capsule and syrup.
Dose and Preparations
The dose of hydrocodone depends on the intensity of pain and the response of the patient. However, tolerance to hydrocodone can develop with continued use and much higher doses are required to decrease pain. In addition, with increased use of the drug, the incidence of side effects also increases.
Hydrocodone is always combined with acetaminophen/ibuprofen/antihistamine as a prescription. The dose of acetaminophen may vary from 350-650 mg. The dose of hydrocodone may vary from 5-15 mg. Various combination of this mixture are available. Hydrocodone is usually taken 3-4 times a day to relieve moderate or severe pain. The dose of hydrocodone should not exceed more than 40 mg in a day and the dose of acetaminophen should not exceed 3-4000 mg per day (8-12 tablets per day).
In the United States, pure hydrocodone is rarely prescribed and is considered a Schedule 2 drug, requiring DEA certificate for prescription. Hydrocodone when it is prescribed with acetaminophen is classified as a Schedule 3 drug and available only with a prescription.
Available Hydrocodone Formulations
Generic names for hydrocodone include:
Therapeutic combinations of hydrocodone and acetaminophen are available as Vicodin and Lortab. When combined with aspirin, the product is sold as Lortab ASA. When combined with ibuprofen, the product is sold as vicoprofen and when combined with an anti-histamine, the product is sold as hycodan.
The most frequently observed adverse reactions include:
These effects are more common when the inpidual is active, and these adverse reactions may be alleviated if the patient lies down.
Hydrocodone is also known to impair judgment and can cause mental sluggishness and clouding. Hydrocodone should be used with great care in patients with head trauma as it can cloud the symptoms of head injury. The drug can produce adverse reactions which may obscure the clinical course of patients with head injuries.
To prevent inpiduals from taking excessive hydrocodone, all available hydrocodone products are formulated with acetaminophen. Acetaminophen is not pleasant when taken in high doses. However, because acetaminophen is soluble in water, it can be extracted in warm water, leaving only the pure form of hydrocodone available for consumption. Following an acute over dosage, toxicity may result from hydrocodone or acetaminophen.
Signs and Symptoms
At high doses or in sensitive patients, hydrocodone may produce dose-related respiratory depression by acting directly on the brain stem respiratory center. Hydrocodone may also affect the center that controls respiratory rhythm, and may produce irregular and shallow breathing.
Life threatening respiratory depression can occur when hydrocodone is taken in high doses. The inpidual may start to show increasing levels of lethargy, somnolence and a cold clammy skin. This is soon followed by a slowing of the heart and respiratory rate. In the final stages, there is collapse of the circulatory system followed by cardiac arrest.
Acetaminophen is a component in the formulation of hydrocodone. Overdose from acetaminophen can lead to severe liver toxicity. Early symptoms following an overdose of acetaminophen may include:
- General Malaise
The liver toxicity usually reaches its peak in 48-72 hours and if not treated, can lead to death. Numerous cases of fatal liver disease have been known to occur. For this reason, oxycontin has now become the preferred agent for illicit drug use.
Other acetaminophen related side effects include:
- Kidney Damage
- Hypoglycemic (drop in blood sugar)
- Thrombocytopenia (decrease in platelets)
Like all narcotics, hydrocodone can cause constipation, slow down the respiration and occasionally cause difficulty in urination. Hydrocodone should not be taken by anyone who has shown a previous allergic reaction to the products. Inpiduals who are sensitive to other opioids, may show a cross sensitivity to hydrocodone.
The major reason why hydrocodone is formulated in combination with other drugs is to increase the analgesic activity and to prevent the side effects of hydrocodone when it is taken at higher doses.
All patients with hydrocodone/acetaminophen overdose require urgent hospitalization. Treatment requires prevention of more absorption of the drug from the stomach and protection of the respiratory and circulatory systems. The majority of patients require ICU admission for medical care because hydrocodone is a narcotic derivate; naloxone (a narcotic antagonist) is almost always used to reverse the poisoning.
If acetaminophen toxicity has occurred and if the inpidual is seen in a hospital within 24 hours of the poisoning, acetylcysteine should be administered as soon as possible. This agent may help protect the liver.
Withdrawal and Interactions
Repeated hydrocodone use can lead to habitual craving and lead to both physical and psychological dependence. Inpiduals who take hydrocodone for prolonged periods, sudden stoppage of the medication can lead to withdrawal symptoms such as:
- Extreme Anxiety
- Difficulty Breathing
- Lack of concentration
- Intense craving for the drug
Hydrocodone is a CNS depressant; it can interact with other chemical or substances which are also CNS suppressants. When taken with alcohol, the inpidual may feel drowsy and sedated. Lethargy can set in and most patients will feel tired and fatigued. Overdose can occur when large doses of alcohol are consumed with hydrocodone. Occasionally respiratory and fatal cardiac arrest can also occur. For this reason, hydrocodone and alcohol should never be combined.
Hydrocodone contains acetaminophen which can cause severe liver injury when taken in high does, alcohol is definitely contraindicated. Alcohol, itself is also a potent agent which can cause liver injury and the combination of acetaminophen and alcohol can cause fatal liver injury.
Hydrocodone can also interact with numerous other centrally acting agents, including tricyclic antidepressants, anti-psychotics and sedatives. A doctor’s advice should be obtained before taking hydrocodone in the presence of such medications. It is not recommended that the drug be taken by pregnant females as it may affect the fetus.
The major concern with long term consumption with hydrocodone is that it can lead to physical and psychological dependence. One of the major reasons why hydrocodone is abused is because of the mood changes associated with the agent. The mental slowing, somnolence and lessening of any anxiety are the major reasons why this drug is abused. The time period of drug consumption which leads to dependence is variable but may range anywhere from 6-12 months of continued use. Dependence and addiction to this drug is usually treated with slow withdrawal of the drug, use of methadone, psychological and supportive therapy through an effective drug rehab program.
- Hydrocodone and Aspirin (Damason P, Mason). In: PDR Physicians' desk reference. 49th ed. 1995. Montvale, NJ: Medical Economics Data Production Company, 1995: 1434.
- Gutstein, HB.; Akil, H. Opioid analgesics. In: Hardman JG, Limbird LE. , editors. In Goodman and Gilman’s The Pharmacological Basis of Therapeutics. 10th ed. New York, NY: McGraw-Hill; 2001.
- Savage SR. Opioid use in the management of chronic pain. Med Clin North Am. 1999; 83:761–786.
- Stein CS. The control of pain in peripheral tissue by opioids. N Engl J Med. 1995; 332:1685–1690.
- Internal Analgesics and Antipyretics Table. In: Krogh CME, editor. Self-Medication Product Information. Volume 2, 4th edition. Canadian Pharmaceutical Association, 1993: 205, 207, 208, 211.