Propoxyphene hydrochloride
Propoxyphene hydrochloride (Darvon)
Propoxyphene
(proh- POX-ih-feen)
Pregnancy Category: C 642 Tablets Darvon Novo-Propoxyn (C-IV) (Rx)
Propoxyphene napsylate
Propoxyphene napsylate (Darvon-N)
Propoxyphene
(proh- POX-ih-feen)
Pregnancy Category: C Darvon-N (C-IV) (Rx)

Classification: Analgesic, narcotic, miscellaneous

Action/Kinetics: Resembles narcotics with respect to its mechanism and analgesic effect; it is one-half to one-third as potent as codeine. Is devoid of antitussive, anti-inflammatory, or antipyretic activity. When taken in excessive doses for long periods, psychologic dependence and occasionally physical dependence and tolerance will be manifested. Peak plasma levels: h ydrochloride: 2-2.5 hr; napsylate: 3-4 hr. Analgesic onset: 30-60 min. Peak analgesic effect: 2-2.5 hr. Duration: 4-6 hr. Therapeutic serum levels: 0.05-0.12 mcg/mL. t 1/2, propoxyphene: 6-12 hr; norpropoxyphene: 30-36 hr. Extensive first-pass effect; metabolites are excreted in the urine.

Uses: Relief of mild to moderate pain. Napsylate has been used experimentally to suppress the withdrawal syndrome from narcotics.

Contraindications: Hypersensitivity to drug. Use in children or in those who are suicidal or addiction-prone.

Special Concerns: Safe use during pregnancy has not been established. Use with caution during lactation.

Side Effects: GI: N&V;, constipation, abdominal pain. CNS: Sedation, dizziness, lightheadedness, headache, weakness, euphoria, dysphoria. Other: Skin rashes, visual disturbances. Propoxyphene can produce psychologic dependence, as well as physical dependence and tolerance.

Overdose Management: Symptoms: Stupor, respiratory depression, apnea hypotension, pulmonary edema, circulatory collapse, cardiac arrhythmias conduction abnormalities, coma, seizures respiratory-metabolic acidosis. Treatment: Maintain an adequate airway, artificial respiration, and naloxone, 0.4-2 mg IV (repeat at 2- to 3-min intervals) to combat respiratory depression. Gastric lavage or administration of activated charcoal may be helpful. Correct acidosis and electrolyte imbalance. Acidosis due to lactic acid may require IV sodium bicarbonate.

Drug Interactions: Alcohol, antianxiety drugs, antipsychotic agents, narcotics, sedative-hypnotics / Concomitant use drowsiness, lethargy, stupor, respiratory depression, and coma Carbamazepine / Carbamazepine effects R/T liver breakdown Charcoal / Propoxyphene absorption from GI tract CNS depressants / Additive CNS depression Orphenadrine / Concomitant use confusion, anxiety, and tremors Phenobarbital / Phenobarbital effects R/T liver breakdown Protease inhibitors / Do not use together Skeletal muscle relaxants / Additive respiratory depression Warfarin / Warfarin hypoprothrombinemic effects

How Supplied: Propoxyphene hydrochloride: Capsule: 65 mg; Propoxyphene napsylate: Tablet: 100 mg

Dosage
?Capsules (Hydrochloride) Analgesia.
Adults: 65 mg q 4 hr, not to exceed 390 mg/day.
?Tablets (Napsylate) Analgesia.
Adults: 100 mg q 4 hr, not to exceed 600 mg/day. Reduce the dose of propoxyphene in renal or hepatic impairment.