DRUG INTERACTIONS with Norvir (ritonavir) 4/10/96

The following list was compiled and distributed by Abbott Labs.

Norvir should NOT be coadministered with:

drug class: analgesic

• meperidine (Demoral)
• piroxicam (Feldene)
• propoxyphene (Darvon)

Potential alternatives (may not be therapeutically equivalent):

• acetaminophen (Tylenol) n=135
• aspirin n=43
• oxycodone (Percodan) n=23

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drug class: cardiovascular (antiarrhythmic)

• amiodarone (Cordarone)
• encainide (Enkaid)
• flecainide (Tambocor)
• propafenone (Rythmol)
• quinidine

potential alternatives: very limited clinical experience; no alternatives are recommended

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drug class: anti-mycobacterial

• rifabutin (Mycobutin)

Potential alternatives:

• clarithromycin (Biaxin) n=156
• ethambutol (Myambutol) n=66

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drug class: cardiovascular (calcium channel blocker)

• bepridil (Vascor)

potential alternatives: very limited clinical experience; no alternatives recommended

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drug class: cold & allergy (antihistimine)

• astemizole (Hismanal)
• terfenadine (Seldane)

potential alternatives:

• loratadine (Claritin) n=36

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drug class: gastrointestinal

• cisapride (Propulsid)

potential alternatives: very limited clinical experience; no alternatives recommended

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drug class: psychotropic (antidepressant)

• bupropion (Wellbutrin)

potential alternatives:

• fluoxetine (Prozac) n=28
• desipramine (Nopramin)

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drug class: psychotropic (neuroleptic)

• clozapine (Clozaril)

potential alternatives: very limited clinical experience; no alternatives recommended

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drug class: psychotropic (sedative/hypnotic)

• aplrazolam (Xanax)
• clorazepate (Tranxene)
• diazepam (Valium)
• estazolam (Prosom)
• flurazepam (Dalmane)
• midazolam (Versed)
• triazolam (Halcion)
• zolpidem (Ambien)

potential alternatives:

• temazepam (Restonil) n=40
• lorazepam (Ativan) n=33

DO NOT CO-ADMINISTER antabuse with Norvir. Ritonavir contains alcohol, which can produce reactions when coadministered with disulfiram (antabuse) or other drugs that produce disulfiram-like reactions (e.g., metronidazole).

see the PRECAUTIONS-DRUG INTERACTIONS and the DRUG-DRUG INTERACTIONS sections of the Norvir package insert for more information about actual and potential effects on drugs coadministered with Norvir; this package insert is available at your pharmacy.

The following statements are quoted from the Abbott package insert. Please, refer to the insert for elaboration of the subjects.

• Tobacco use is associated with an 18% decrease in the AUC (blood levels) of ritonavir."
• Relative to fasting conditions, the extent of absorption of ritonavir from the capsule formulation was 15% higher when administered with a meal (771 KCal; 46% fat, 18% protein, and 37% carbohydrate)." -- see the PHARMACOKINETICS section of the package insert.

See also, Letter from Abbott sent to doctors.