PROPOXYPHENE HYDROCHLORIDE

PROPOXYPHENE HYDROCHLORIDE
(proe-pox'i-feen)
Darvon 642

, Novopropoxyn

PROPOXYPHENE NAPSYLATE
Darvon-N
Classifications: narcotic (opiate) agonist, analgesic;
Therapeutic: narcotic analgesic, agonist
Prototype: Morphine
Pregnancy Category: C (D for prolonged use or at term)
Controlled Substance: Schedule IV

Availability

Napsylate: 100 mg tablets

Hydrochloride: 65 mg capsules

Action

Centrally acting opioid structurally related to methadone. Acts as a weak agonist at opiate receptors within the CNS. Analgesic potency about ? –2/3 that of codeine.

Therapeutic Effect

Potent analgesic.

Uses

Relief of mild to moderate pain.

Unlabeled Uses

To suppress narcotic withdrawal symptoms.

Contraindications

Hypersensitivity to drug; suicidal individuals; alcoholism; dependence on opiates; safety during pregnancy [category C (D for prolonged use or at term)] or in children is not established.

Cautious Use

Kidney or liver disease; cardiac disease; biliary tract disease; pulmonary insufficiency.

Route & Dosage

Mild to Moderate Pain
Adult: PO 65 mg HCl or 100 mg napsylate q4h prn (max: 390 mg HCl/d, 600 mg napsylate/d)

Administration

Note: 100 mg napsylate = 65 mg HCl

Empty capsules and mix contents with water or food if unable to swallow capsule whole.
Be aware that absorption may be delayed by presence of food in stomach.
Store at 15°–30° C (59°–86° F).

Adverse Effects (≥1%)

CNS: Dizziness, light-headedness, drowsiness, sedation, unusual fatigue or weakness, restlessness, tremor, euphoria, dysphoria, headache, paradoxic excitement, mental confusion, toxic psychosis, coma, convulsions. GI: Nausea, vomiting, abdominal pain, constipation, liver dysfunction. Special Senses: Minor visual disturbances, pinpoint pupils (dilate with advancing hypoxia). Skin: Skin eruptions (hypersensitivity). Metabolic: Hypoglycemia (patients with impaired kidney function), acidosis, nephrogenic diabetes insipidus. Respiratory: Respiratory depression, pulmonary edema. CV: Circulatory collapse, ECG abnormalities.

Interactions

Drug: Alcohol and other cns depressants add to CNS depression, also fatalities reported with alcohol use; may increase hypoprothrombinemic effects of warfarin; may increase carbamazepine toxicity through decreased metabolism; orphenadrine increases CNS stimulation, anxiety, tremors, confusion. Herbal: St. John's wort may increase sedation.

Pharmacokinetics

Absorption: Readily from upper part of small intestine. Onset: 15–60 min. Peak: 2–3 h. Duration: 4–6 h. Distribution: Crosses placenta; distributed into breast milk. Metabolism: In liver. Elimination: In urine. Half-Life: 6–12 h, 30–36 h for metabolite.

Nursing Implications

Assessment & Drug Effects

Evaluate need for drug since abuse potential is high.
Monitor CNS effects, respiratory status and therapeutic effectiveness.
Overdose: Prompt action required; fatalities occur commonly within first hour following overdosage.

Patient & Family Education

Do not drive or engage in potentially hazardous activities until response to drug is known.
Do not exceed recommended dose; do not use alcohol and other CNS depressants with propoxyphene.
Lie down if dizziness, light-headedness, drowsiness, nausea, or vomiting occur while ambulating.
Be aware that tolerance and physical or psychic dependence of the morphine type can occur with excessive use.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

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