What is codeine? How does it work (mechanism of action)?
Codeine is a narcotic pain-reliever and cough suppressant similar to morphine and hydrocodone. Moreover, a small amount of codeine is converted to morphine in the body. The precise mechanism of action of codeine is not known; however, like morphine, codeine binds to receptors in the brain (opioid receptors) that are important for transmitting the sensation of pain throughout the body and brain. Codeine increases tolerance to pain, decreasing discomfort, but the pain still is apparent to the patient. In addition to reducing pain, codeine also causes sedation drowsiness and depresses breathing. Codeine frequently is combined with acetaminophen (Tylenol) or aspirin for more effective pain relief. The FDA approved codeine in 1950.
What are the uses for codeine?
Codeine is used for the relief of mild to moderately severe pain and for suppressing cough.
What are the side effects of codeine?
The most frequent side effects of codeine include:
- Lightheadedness
- Dizziness
- Nausea
- Vomiting
- Shortness of breath
- Sedation
- Allergic reactions
- Constipation
- Abdominal pain
- Rash
- Itching
Serious side effects of codeine include:
- Life-threatening respiratory depression
- Severe low blood pressure
- Adrenal insufficiency
- Accidental ingestion of codeine can result in fatal overdose
Is codeine addictive? Is it a controlled substance?
Codeine is habit forming (addictive). Mental and physical dependence can occur but are unlikely when used for short-term pain relief. Using codeine during pregnancy can cause opioid withdrawal syndrome in the newborn, which may be life-threatening if not treated.
If codeine is suddenly withdrawn after prolonged use, symptoms of withdrawal may develop. The dose of codeine should be reduced gradually in order to avoid withdrawal symptoms.
QUESTION
Medically speaking, the term “myalgia” refers to what type of pain?
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Can I drink alcohol with codeine? What other drugs interact with codeine?
- Codeine can impair thinking and physical abilities required for driving or operating machinery.
- Alcohol and other sedatives such as alprazolam (Xanax) can produce further brain impairment and even confusion when combined with codeine. Therefore, alcohol and other sedatives should not be used when taking codeine.
- Drugs that stimulate and also block opioid receptors (for example, pentazocine) reduce the effect of codeine. Such drugs should not be combined with codeine.
- Drugs that block the action of acetylcholine (anticholinergic drugs) increase the occurrence of urinary retention and constipation when combined with codeine.
- Monoamine oxidase inhibitors (MAOIs) class of antidepressants (for example, isocarboxazid [Marplan], phenelzine [Nardil], tranylcypromine [Parnate], selegiline [Eldepryl], and procarbazine [Matulane]) significantly increase the action of codeine. Codeine should not be used in patients taking MAOIs or within 14 days of stopping MAOIs.
What is the dosage for codeine? How is it taken?
- The usual adult dose of codeine for pain is 15-60 mg every 4-6 hours as needed.
- The dose for cough is 10 to 20 mg every 4-6 hours as needed.
- The maximum dose for treating cough is 120 mg every 24 hours.
Is it safe to take codeine if I am pregnant or breastfeeding?
Small amounts of codeine are secreted in breast milk, but the risk of adverse events in the infant is small.
What else should I know about codeine?
Codeine is available as:
- Tablets: 15, 30, 60 mg.
- Solution: 15 mg/5ml (teaspoon).
- Injection: 15 and 30 mg/ml.
Codeine should be stored between 15 C to 30 C (59 F to 86 F).
You need a prescription from your doctor to obtain codeine.