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.
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.
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.