Fentanyl

Brand names

• Actiq
• Duragesic
• Innovar
• Oralet
• Sublimaze

Usage

To control severe chronic pain.

How it works

Fentanyl, a narcotic, relieves pain by acting on specific areas of the spinal cord and brain that process pain signals from nerves throughout the body.

Side effects

Serious

Seizures, severe drowsiness, hallucinations, slow heartbeat, very slow or weak breathing, cold, clammy skin, pinpoint pupils of eyes.

Common

Dizziness, nausea or vomiting, constipation, drowsiness, urine retention, itching.

Less common

Sweating, skin reaction at patch site, rigid muscles, fainting, jerking body movements (myoclonus).

Possible interactions

Other medicaments:

Fentanyl may increase the effects of:

• benzodiazepines such as diazepam (Valium) and alprazolam (Xanax).
• central nervous system depressants such as opiates, barbiturates, tranquilizers and tricyclic antidepressants.

Fentanyl taken concurrently with:



• amiodarone (Cordarone) may result in heart (cardiac) toxicity.
• clonidine (Catapres, others) may result in greater than expected fentanyl effects. The fentanyl dose may need to be decreased if these medicines are to be combined.
• MAO inhibitors may worsen the lowering of blood pressure and depression of breathing seen with fentanyl.
• rifabutin (Mycobutin) may decrease pain control by fentanyl.
• ritonavir (Norvir) and perhaps other protease inhibitors can lead to major fentanyl toxicity.
• sibutramine (Meridia) may increase risk of serotonin syndrome. Do not combine.
• sildenafil (Viagra) may lead to changes in sildenafil or in fentanyl levels.

Herbal medicines or minerals:

Valerian and kava kava may interact additively (drowsiness). Avoid these combinations. St. John's wort can change (inducing or increasing) P450 3A4 or 2D6 enzymes, blunting the effects of fentanyl. Talk to your doctor before you combine any herbal medicines with fentanyl.

Alcohol:

Do not drink alcohol while you are taking this medicament-leads to additive loss of mental status, respiratory depression and confusion.

Marijuana smoking:

Additive adverse effects; however, marijuana may block the vomiting effect of fentanyl.

Discontinuation:

Once the patch is removed, fentanyl will still be released from the site for 17 hours or more. If pain medicine is still needed, the alternative should be substituted once the fentanyl level is low enough. The level from the lozenge declines more rapidly, and replacement medicine is required sooner if the fentanyl lozenge is stopped. If the lozenge has been used routinely, the medicament should be slowly tapered, not stopped abruptly.