Darvon (Propoxyphene) Side Effects & Warnings

Propoxyphene, also referred to as dextropropoxyphene, is a comparatively weak synthetic opioid analgesic previously sold in the United States under the brand names Darvon, Darvon-N, and Darvocet.

In various forms, including propoxyphene, propoxyphene hydrochloride, and propoxyphene napsylate, the drug was widely prescribed to treat mild to moderate pain, chronic pain, and diarrhea. It was also often used in combination with the over-the-counter pain relievers acetaminophen and aspirin.

As of 2010, however, all propoxyphene products have been taken off the market in the United States due to concerns over fatal overdoses and effects related to heart function. 

Tramadol, another analgesic medication in the opioid class, has been recommended as an alternative treatment due to its equally mild effects, lower potential for misuse or addiction, and lack of cardiotoxic side effects.

Common Side Effects Of Propoxyphene

The most common side effects associated with the use of propoxyphene may include:

• blurred vision  
• constipation
• dizziness
• drowsiness
• headache
• itching
• lightheadedness
• muscle pain
• nausea
• skin rash
• sleepiness
• sore throat
• stomach pain
• vomiting

Serious Side Effects Of Propoxyphene

Adverse effects and other serious side effects related to propoxyphene use have been reported. If you experience any of the following effects after taking this drug, report them to your healthcare provider or seek medical attention:

• confusion
• fainting
• hallucinations
• jaundice (yellowing of the skin or eyes)
• lightheadedness
• seizure (convulsions)
• shallow breathing
• slow heartbeat
• arrhythmias
• unusual thoughts or behavior

Why Propoxyphene Is No Longer Used

Healthcare providers in the United States have a wide variety of opiate painkillers available to meet different patients’ needs. 

In the case of propoxyphene, a drug introduced to the US in 1957, widespread use eventually revealed that this particular medication’s side effects were severe and dangerous, including: 

• fatal changes in heart rate and heart rhythm
• heart attack
• stroke)
• seizures
• suicidal impulses and attempts

Following the FDA ban on propoxyphene, other prescription drugs with lower risk profiles have been used in the drug’s place, including tramadol, codeine, hydrocodone, and others.

Propoxyphene Warnings

As an opioid drug, propoxyphene acts as a strong central nervous system depressant. Taking too much propoxyphene can cause fatal overdose effects, particularly if a person is also drinking alcohol or has taken a sedative, antidepressant, or some other CNS depressant substance.

Propoxyphene Overdose

Signs and symptoms of an overdose on propoxyphene, also called propoxyphene toxicity, will likely resemble overdoses of other opioids and may include:

• extreme drowsiness
• constricted, pinpoint pupils
• mental confusion
• cold, clammy skin
• blue-tinted fingertips or lips
• weak, unsteady pulse
• gasping or gurgling
• slow, shallow, or interrupted breathing (respiratory depression)
• loss of consciousness or unresponsiveness

Propoxyphene overdose can be rapidly treated with the opioid receptor antagonist naloxone (Narcan), which is widely available and carried by first responders. 

Propoxyphene Withdrawal

Propoxyphene is habit forming, meaning that prolonged use or abuse will generate physical dependence and eventual withdrawal symptoms when a person stops taking it.

These withdrawal symptoms include both physical and psychological effects such as: 

• nausea and vomiting
• fever
• gastrointestinal problems
• changes in blood pressure
• flu-like illness
• anxiety, depression, insomnia
• severe cravings that can provoke relapse

For this reason, the FDA advised chronic pain patients to not stop taking propoxyphene medications abruptly. Instead, they should seek medical advice and either taper off the medication or switch to another pain management med.

Propoxyphene withdrawal symptoms can also be managed through medical detoxification programs, as is true with withdrawal syndromes related to other prescription drug abuse.

Other Precautions

There are a number of drug interactions associated with propoxyphene, including dangerous interactions with other CNS depressants and drugs that induce or inhibit the activity of the CYP3A4 enzyme, which predominantly metabolizes propoxyphene in the human body.

Propoxyphene itself is also thought to inhibit the activity of the CYP3A4 and CYP2D6 enzymes, and as a result the drug should not be taken with carbamazepine due to a high risk of serious neurological issues.

Propoxyphene should also not be taken within 14 days of a MAOI, due to the risk of another serious drug interaction.

Additional precautions listed in propoxyphene’s drug information include:

• risk of hypotension
• risks related to head injuries and increased intracranial pressure
• risks related to pregnancy and breastfeeding, including a risk of fetal harm and withdrawal symptoms in newborns
• increased risk when prescribed to older adults

If you or a loved one live with prescription opioid addiction and need help, contact Ohio Recovery Center for information on our inpatient treatment options.