Codeine Side Effects, Warnings, and Interactions

Codeine is a narcotic (opioid) pain reliever and cough suppressant similar to morphine and hydrocodone used to relieve mild to moderately severe pain and to suppress cough.

Common side effects of codeine include lightheadedness, dizziness, nausea, vomiting, shortness of breath, sedation, allergic reactions, constipation, abdominal pain, rash, and itching.

Serious side effects of codeine include life-threatening respiratory depression, severe low blood pressure, adrenal insufficiency, and accidental ingestion that can result in fatal overdose.

Codeine is habit forming (addictive). Mental and physical dependence can occur but are unlikely when used for short-term pain relief.  If codeine is suddenly withdrawn after prolonged use, withdrawal symptoms may develop.

Drug interactions of codeine include alcohol and other sedatives, drugs that stimulate and also block opioid receptors (for example, pentazocine), anticholinergic drugs, and monoamine oxidase inhibitors (MAOIs).

Using codeine during pregnancy can cause opioid withdrawal syndrome in the newborn, which may be life-threatening if not treated. Small amounts of codeine are secreted in breast milk, but the risk of adverse events in the infant is small.

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

The most frequent adverse reactions include lightheadedness, dizziness, sedation, nausea, and vomiting. These effects seem to be more prominent in ambulatory than in non ambulatory patients, and some of these adverse reactions may be alleviated if the patient lies down.

Other adverse reactions include euphoria, dysphoria, constipation, and pruritus.

Controlled Substance: Codeine phosphate is a Schedule II narcotic.

Dependence

Although much less potent in this regard than morphine, codeine can produce drug dependence a.d. therefore, has the potential for being abused. Patients given 60 mg codeine every 6 hours for 2 months usually show some tolerance and mild withdrawal symptoms. Development of the dependent state is recognized by an increased tolerance to the analgesic effect and the appearance of purposive phenomena (complaints, pleas, demands, or manipulative actions) shortly before the time of the next scheduled dose. A patient in withdrawal should be treated in a hospital environment. Usually, it is necessary only to provide supportive care with administration of a tranquilizer to suppress anxiety. Severe symptoms of withdrawal may require administration of a replacement narcotic.

Codeine in combination with other narcotic analgesics, general anesthetics, phenothiazines, tranquilizers, sedative-hypnotics, or other CNS depressants (including alcohol) has additive depressant effects. When s.c. combination therapy is contemplated, the dosage of one or both agents should be reduced.