Codeine Phosphate

Patient Information about Codeine Phosphate

Codeine may impair the mental and/or physical abilities required for the performance of potentially hazardous tasks, s.c. as driving a car or operating machinery. Codeine in combination with other narcotic analgesics, phenothiazines, sedative hypnotics, and alcohol has additive depressant effects.

Description of Codeine Phosphate

WARNING – MAY BE HABIT FORMING

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 of Codeine Phosphate

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.

How Supplied the Codeine Phosphate

No information provided.

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.

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.

Drug Interactions

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.

No information provided.

Precautions

General

Head Injury and Increased Intracranial Pressure: The respiratory depressant effects of narcotics and their capacity to elevate cerebrospinal-fluid pressure may be markedly exaggerated in the presence of head injury, other intracranial lesions, or a preexisting increase in intracranial pressure. Furthermore, narcotics produce adverse reactions that may obscure the clinical course in patients with head injuries.

Acute Abdominal Conditions: The administration of codeine or other narcotics may obscure the diagnosis or clinical course in patients with acute abdominal conditions.

Special-Risk Patients: Codeine should be given with caution to certain patients, s.c. as the elderly or debilitated and those with severe impairment of hepatic or renal function, hypothyroidism, Addison’s disease, and prostatic hypertrophy or urethral stricture.

Kidney or Liver Dysfunction: Codeine phosphate may have a prolonged cumulative effect in patients with kidney or liver dysfunction.

Information for the Patient

Codeine may impair the mental and/or physical abilities required for the performance of potentially hazardous tasks, s.c. as driving a car or operating machinery. Codeine in combination with other narcotic analgesics, phenothiazines, sedative hypnotics, and alcohol has additive depressant effects.

Pregnancy

Pregnancy Category C Animal reproduction studies have not been conducted with codeine phosphate. It is also not known whether codeine phosphate can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. On the basis of the historical use of codeine phosphate during all stages of pregnancy, there is no known risk of fetal abnormality. Codeine phosphate should be given to a pregnant woman only if clearly needed.

Labor and Delivery

The use of codeine phosphate in obstetrics may prolong labor. It passes the placental barrier and may produce depression of respiration in the newborn. Resuscitation a.d. in severe depression, the administration of naloxone may be required.

Nursing Mothers

Codeine appears in the milk of nursing mothers. Caution should be exercised when it is administered to a nursing woman.

Signs and Symptoms

Codeine is metabolized to morphine and its effects are similar to those of morphine and other opiate analgesics. Respiratory depression, sedation and miosis and common symptoms of overdose. Other symptoms include nausea, vomiting, skeletal muscle flaccidity, bradycardia, hypotension, and cool, clammy skin. Apnea and death may ensue; children have had apnea after doses as small as 5 mg/kg. Noncardiac pulmonary edema may develop opioid overdose, and monitoring of heart filling pressure may be helpful.

Treatment

To obtain up-to-date information about the treatment of overdose, a good resource is your Certified Regional Control Center. Telephone numbers of certified poison control centers are listed in the beginning of Physicians GenRx. In managing overdosage, consider the possibility of multiple drug overdoses, interaction among drugs, and unusual drug kinetics in your patient.

Naloxone antagonizes most effects of codeine. Protect the airway as Naloxone may induce vomiting. Naloxone has a shorter duration of action than codeine; repeated doses may be needed. In patients who abuse opioids chronically, a withdrawal syndrome may be manifest on administration of naloxone. This may include yawning, tearing, restlessness, sweating, dilated pupils, piloerection, vomiting, diarrhea, and abdominal cramps. This syndrome usually abates quickly as the effect of naloxone dissipates.

Protect the patient’s airway and support ventilation and perfusion. Meticulously monitor and maintain, within acceptable limits, the patient’s vital signs, blood gases, serum electrolytes, etc. Absorption of drugs from the gastrointestinal tract may be decreased by giving activated charcoal, which in many cases, is more effective than emesis or lavage; consider charcoal instead of or in addition to gastric emptying. Repeated doses of charcoal over time may hasten elimination of some drugs that have been absorbed. Safeguard the patient’s airway when employing gastric emptying or charcoal.

Forced diuresis, peritoneal dialysis, hemodialysis, or charcoal hemoperfusion have not been established as beneficial for an overdose of codeine phosphate.

Contraindications

Hypersensitivity to codeine.

Codeine phosphate is a centrally active analgesic. When administered parenterally, 120 mg of codeine phosphate produces an analgesic response equivalent to that from 10 mg of morphine. Other actions include respiratory depression; depression of the cough center; release of antidiuretic hormone; activation of the vomiting center; pupillary constriction; a decrease in gastric, pancreatic, and biliary secretion; a reduction in intestinal motility; an increase in biliary tract pressure; and an increased amplitude of ureteral contractions.

Onset of analgesia following intramuscular or subcutaneous administration occurs within 10 to 30 minutes. The effect persists for 4 to 6 hours.

Most of a dose of codeine is excreted within 24 hours, 5% to 15% as unchanged codeine and the remainder as a product of glucuronide conjugates of codeine and its metabolites.