Codeine is an alkaloid obtained from opium or prepared from morphine by methylation and occurs as white crystals. Codeine effloresces slowly in dry air and is effected by light. The chemical name of codeine phosphate is 7,8-Didehydro-4,5alpha-epoxy-3-methoxy-17-methylmorphinan-6alpha-ol phosphate (1:1)(salt) hemihydrate and has the empirical formula of C18H21NO3·H3PO4·1/2H20. Its molecular weight is 406.4.
Each soluble tablet contains 30 mg (0.074 mmol) or 60 mg (0.15 mmol) of codeine phosphate. These tablets also contain lactose and sucrose.
Soluble tablets of codeine phosphate are freely soluble in water. They are intended for the preparation of solutions for parenteral administration. These tablets are not sterile. Codeine phosphate is an analgesic.
Codeine phosphate is an analgesic indicated for the relief of mild to moderate pain.
DOSAGE AND ADMINISTRATION
For Analgesia: Dosage should be adjusted according to the severity of the pain and the response of the patient.
Adults: 15 to 60 mg every 4 to 6 hours (usual adult dose, 30 mg).
Children: 1 Year of Age and Older – 0.5 mg/kg of b.d. weight or 15 mg/m2 of b.d. surface every 4 to 6 hours.
Soluble tablets codeine phosphate are administered subcutaneously or intramuscularly.
Solutions for injection should be prepared with sterile water and filtered through a 0.22 membrane filter.
Note: Do not use the solution if it is more than slightly discolored or contains a precipitate.
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.
Drug Abuse and Dependence
Controlled Substance: Codeine phosphate is a Schedule II narcotic.
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.