Darvon Side Effects

Generic name: propoxyphene

Note: This document contains side effect information about propoxyphene. Some of the dosage forms listed on this page may not apply to the brand name Darvon.

Some side effects of Darvon may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

For the Consumer

Applies to propoxyphene: oral capsule, oral tablet

Get emergency medical help if you have any of these signs of an allergic reaction while taking propoxyphene (the active ingredient contained in Darvon) hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have any of these serious side effects:

• shallow breathing, slow heartbeat;

• feeling light-headed, fainting;

• confusion, hallucinations, unusual thoughts or behavior;

• seizure (convulsions); or

• jaundice (yellowing of the skin or eyes).

Less serious side effects include:

• feeling dizzy or drowsy;

• nausea, vomiting, stomach pain, constipation;

• headache, muscle pain;

• blurred vision; or

• mild skin rash.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects.

For Healthcare Professionals

Applies to propoxyphene: oral capsule, oral tablet

General

In general, the adverse effects of propoxyphene (the active ingredient contained in Darvon) may be more likely and more severe in patients with renal and/or liver disease.

General side effects including drug tolerance and influenza type illness have been reported.

Nervous system

Nervous system side effects have included dizziness, sedation, stupor, delirium, somnolence, ataxia, coma, syncope, and respiratory depression. The sedative effects of propoxyphene (the active ingredient contained in Darvon) have been associated with a 60% increased risk of hip fracture in elderly patients.

Other

Other side effects have included dependence (although the abuse liability of propoxyphene (the active ingredient contained in Darvon) is less than that of some other narcotic analgesics). Withdrawal symptoms after either abrupt cessation or fast tapering may occur and include agitation, restlessness, anxiety, insomnia, tremor, tachycardia, hallucinations, psychosis, abdominal cramps, vomiting, sweating, and seizures.

Drug toxicity, multiple drug overdose, and narcotic overdose have also been reported.

Sensorineural deafness has been reported following chronic abuse and/or large doses of propoxyphene-containing compounds. Optic atrophy has been reported following overdose.

Cardiovascular

Cardiovascular side effects have included arrhythmia, bradycardia, cardiac/respiratory arrest, congestive arrest, congestive heart failure (CHF), tachycardia, myocardial infarction (MI), hypotension, decreased blood pressure, elevated heart rate, abnormal heart rate, and dizziness. A variety of arrhythmias (including heart block) have been reported most often in association with propoxyphene (the active ingredient contained in Darvon) overdose.

Some of the cardiotoxic effects reported in association with propoxyphene may be attributable to its major active metabolite, norpropoxyphene.

Gastrointestinal

Gastrointestinal side effects have included nausea, vomiting, and constipation which have been relatively common. Gastrointestinal bleeding and acute pancreatitis have also been reported.

A case of ischemic colitis has been reported following an overdose of propoxyphene which was complicated by severe hypotension.

Genitourinary

Genitourinary side effects including a case of retroperitoneal fibrosis have been reported.

Dermatologic

Dermatologic side effects including rashes and itch have been reported.

Renal

Renal side effects have included a single case of nephrogenic diabetes insipidus following an overdose of propoxyphene (the active ingredient contained in Darvon) (however, other causes of diabetes insipidus in that patient were not rigorously excluded).

Hepatic

Hepatic side effects have included elevated liver function tests, jaundice, hepatic steatosis, hepatomegaly, hepatocellular injury, and hepatotoxicity.

Hematologic

Hematologic side effects have rarely included cases of hemolytic anemia, pancytopenia, and disseminated intravascular coagulation after administration (or abuse) of propoxyphene-containing compounds.

Local

Local side effects have included inadvertent intra-arterial injection with ensuing vascular compromise and distal necrosis has been reported in propoxyphene-abusing patients.

Musculoskeletal

Musculoskeletal side effects including myopathy and rhabdomyolysis have been reported after chronic oral use. Fibrous myopathy has also been reported in propoxyphene-abusing patients who administered the drug via intramuscular injection.

Metabolic

Metabolic side effects including metabolic acidosis have been reported. Cases of severe hypoglycemia have been reported in patients with chronic renal failure.

Ocular

Ocular side effects including eye swelling and vision blurred have been reported.

Hypersensitivity

Hypersensitivity side effects have been reported.

Psychiatric

Psychiatric side effects including abnormal behavior, confusional state, hallucinations, and mental status change have been reported.

Respiratory

Respiratory side effects including dyspnea have been reported.

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