Codeine Phosphate

DESCRIPTION

WARNING- MAY BE HABIT FORMING

Codeine is analkaloidobtained fromopiumor prepared frommorphineby 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 forparenteraladministration. These tablets are not sterile. Codeine phosphate is ananalgesic.

INDICATIONS

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岁及以上- b的0.5毫克/公斤。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

No information provided.

SIDE EFFECTS

The most frequent adverse reactions includelightheadedness, 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 includeeuphoria,dysphoria, constipation, andpruritus.

Drug Abuse and Dependence

Controlled Substance:Codeine phosphate is a Schedule IInarcotic.

Dependence

虽然不如morp强有力的在这方面hine, 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 mildwithdrawal 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 hospitalenvironment. Usually, it is necessary only to providesupportive carewith 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.

警告

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 prostatichypertrophyor urethralstricture.

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 CAnimal 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 inobstetricsmay prolong labor. It passes the placental barrier and may produce depression ofrespirationin the newborn.Resuscitationa.d. in severe depression, the administration ofnaloxonemay be required.

Nursing Mothers

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

OVERDOSE

Signs and Symptoms

Codeine is metabolized to morphine and its effects are similar to those of morphine and otheropiateanalgesics.Respiratory depression, sedation andmiosisand common symptoms of overdose. Other symptoms include nausea, vomiting,skeletal muscleflaccidity,bradycardia,hypotension, and cool, clammy skin.Apneaand death may ensue; children have had apnea after doses as small as 5 mg/kg. Noncardiacpulmonary edemamay developopioidoverdose, 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 drugkineticsin your patient.

纳洛酮对抗大多数可待因的影响。普罗特ect 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 includeyawning, tearing, restlessness, sweating, dilated pupils,piloerection, vomiting, diarrhea, and abdominal cramps. This syndrome usually abates quickly as the effect of naloxone dissipates.

普罗特ect the patient's airway and supportventilationandperfusion. Meticulously monitor and maintain, within acceptable limits, the patient's vital signs, blood gases, serum electrolytes, etc. Absorption of drugs from thegastrointestinal tractmay be decreased by givingactivated charcoal, which in many cases, is more effective thanemesisor lavage; consider charcoal instead of or in addition togastricemptying. 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.

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

CONTRAINDICATIONS

Hypersensitivity to codeine.

CLINICAL PHARMACOLOGY

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 ofantidiuretic hormone; activation of the vomiting center; pupillary constriction; a decrease in gastric, pancreatic, andbiliarysecretion; a reduction in intestinal motility; an increase in biliary tract pressure; and an increased amplitude of ureteral contractions.

Onset ofanalgesiafollowingintramuscularor 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.

PATIENT INFORMATION

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.