Darvon-N

Darvon-N,

trademark for an opioid analgesic (propoxyphene napsylate).

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propoxyphene napsylate Warning - High-alert drug!

Darvon-N

Pharmacologic class: Opioid-like agonist

Therapeutic class: Nonopioid analgesic

Controlled substance schedule IV

Pregnancy risk category C

FDA Boxed Warning

• Don't administer to patients who are suicidal or addiction-prone.
• Give cautiously to patients who take tranquilizers or antidepressants or who use alcohol in excess.
• Advise patient not to exceed recommended dosage and to limit alcohol intake during therapy.
• When used in excessive dosages (alone or in combination with alcohol or other CNS depressants), propoxyphene products are a major cause of drug-related deaths. Deaths may arise within first hour of overdose; many have occurred in patients with history of emotional disturbances or suicidal ideation or attempts or history of misuse of tranquilizers, alcohol, and other CNS drugs.

Action

Alters perception of and emotional response to pain by binding with opiate receptors in brain, causing CNS depression

Availability

propoxyphene hydrochloride

Capsules: 65 mg

propoxyphene napsylate

Tablets: 100 mg

⊘Indications and dosages

➣ Mild to moderate pain

Adults: 65 mg (hydrochloride) P.O. q 4 hours or 100 mg (napsylate) P.O. q 4 hours as needed. Don't exceed 390 mg/day hydrochloride or 600 mg/day napsylate.

Dosage adjustment

• Hepatic or renal impairment
• Elderly or debilitated patients

Contraindications

• Hypersensitivity to drug or its components
• Suicidal or substance abuse-prone patients

Precautions

Use cautiously in:
• head trauma; increased intracranial pressure; severe renal, hepatic, or pulmonary disease; hypothyroidism; adre-nal insufficiency; prostatic hypertrophy; undiagnosed abdominal pain; alcoholism
• patients receiving MAO inhibitors
• elderly or debilitated patients
• pregnant or breastfeeding patients
• children.

Administration

• Give with milk or food to reduce GI upset.
• Be aware that 100 mg propoxyphene napsylate is equivalent to 65 mg propoxyphene hydrochloride.

Route	Onset	Peak	Duration
P.O.	15-60 min	2-3 hr	4-6 hr

Adverse reactions

CNS: dizziness, headache, dysphoria, euphoria, insomnia, paradoxical excitement, asthenia, sedation

CV: hypotension

EENT: blurred vision

GI: nausea, vomiting, constipation, abdominal pain

Skin: rash

Other: physical or psychological drug dependence, drug tolerance

Interactions

Drug-drug. Antidepressants, sedative-hypnotics: additive CNS depression

Buprenorphine, dezocine, nalbuphine, pentazocine: decreased analgesic effect

MAO inhibitors: unpredictable and potentially fatal effects

Partial-antagonist opioid analgesics: precipitation of withdrawal in physically dependent patients

Drug-diagnostic tests. Alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase: altered levels

Drug-herbs. Chamomile, hops, kava, skullcap, valerian: increased CNS depression

Drug-behaviors. Alcohol use: increased CNS depression

Smoking: increased metabolism and decreased analgesic efficacy of propoxyphene

Patient monitoring

• Assess patient's pain level 30 minutes after giving drug.
• Evaluate CNS effects. As needed, institute measures to prevent injury.
• In long-term therapy, monitor liver function tests and evaluate patient regularly for signs of physical or psychological drug dependence.

Patient teaching

• Advise patient to take with milk or food to minimize GI upset.
• Inform patient that drug may cause physical or psychological dependence. Stress that he should take it only when needed and only as prescribed.
• Tell patient that alcohol use and smoking affect drug blood level. Discourage these habits.
• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration, vision, and alertness.
• As appropriate, review all other significant adverse reactions and interactions, especially those related to the drugs, tests, herbs, and behaviors mentioned above.