propoxyphene

propoxyphene

(proe pox' i feen)

propoxyphene hydrochloride (dextropropoxyphene)

Darvon

propoxyphene napsylate

Darvocet-N, Darvon-N

Pregnancy Category C

Controlled substance C-IV

Drug class

Opioid agonist analgesic

Therapeutic actions

Acts as agonist at specific opioid receptors in the CNS to produce analgesia, euphoria, sedation; the receptors mediating these effects are thought to be the same as those mediating the effects of endogenous opioids (enkephalins, endorphins)

Indications

·        Relief of mild to moderate pain

Contraindications and cautions

·        Contraindicated with hypersensitivity to opioids, pregnancy (neonatal withdrawal has occurred; neonatal safety not established), labor or delivery (especially when delivery of a premature infant is expected; opioids given to mother can cause respiratory depression of neonate; may prolong labor), lactation, suicidal or addiction-prone patients.

·        Use cautiously with renal or hepatic dysfunction, emotional depression, excessive alcohol use; use of antianxiety, antidepressant drugs.

Available forms

Capsules—65 mg; tablets—100 mg

Dosages

ADULTS

Propoxyphene hydrochloride

65 mg PO q 4 hr as needed. Do not exceed 390 mg/day.

Propoxyphene napsylate

100 mg PO q 4 hr as needed. Do not exceed 600 mg/day.

PEDIATRIC PATIENTS

Not recommended.

GERIATRIC PATIENTS OR ADULTS WITH HEPATIC OR RENAL IMPAIRMENT

Use caution; reduced dosage may be needed.

Pharmacokinetics

Route	Onset	Peak
Oral	30–60 min	2–2.5 hr

Metabolism: Hepatic; T_1/2: 6–12 hr

Distribution: Crosses placenta; enters breast milk

Excretion: Urine

Adverse effects

·        CNS: Headache, weakness, dizziness, sedation, light-headedness, euphoria, dysphoria, minor visual disturbances

·        Dermatologic: Rashes

·        GI: Nausea, vomiting, constipation, abdominal pain, liver dysfunction

·        Other: Tolerance and dependence, psychological dependence

Interactions

Drug-drug

·        Increased likelihood of respiratory depression, hypotension, profound sedation, or coma with barbiturate general anesthetics

·        Increased serum levels and toxicity of carbamazepine

·        Decreased absorption and serum levels with charcoal

Nursing considerations

Assessment

·        History: Hypersensitivity to opioids, pregnancy, lactation, renal or hepatic dysfunction, emotional depression

·        Physical: Skin color, texture, lesions; orientation, reflexes, affect; bowel sounds, normal output; LFTs, renal function tests

Interventions

·        Administer to lactating women 4–6 hr before the next feeding to minimize the amount in milk.

·        WARNING: Limit amount of drug dispensed to depressed, emotionally labile, or potentially suicidal patients; propoxyphene intake alone or with other CNS depressants has been associated with deaths.

·        WARNING: Keep opioid antagonist and facilities for assisted or controlled respiration on standby in case respiratory depression occurs.

·        Give drug with milk or food if GI upset occurs.

·        Reassure patient about addiction liability; most patients who receive opiates for medical reasons do not develop dependence syndromes.

Teaching points

·        Take drug exactly as prescribed.

·        Do not take leftover medication for other disorders, and do not let anyone else take the prescription.

·        Avoid alcohol intake while using this drug.

·        You may experience these side effects: Nausea, loss of appetite (take drug with food, eat frequent small meals); constipation (request laxative); dizziness, sedation, drowsiness, impaired visual acuity (avoid driving or performing other tasks that require alertness, visual acuity).

·        Report severe nausea, vomiting, constipation, shortness of breath or difficulty breathing.

Adverse effects in Italic are most common; those in Bold are life-threatening.