Norvir

Nor·vir (nôrvîr)

A trademark for the drug ritonavir.

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Norvir,

trademark for a protease inhibitor (ritonavir).

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ritonavir

Norvir

Pharmacologic class: Protease inhibitor

Therapeutic class: Antiretroviral

Pregnancy risk category B

FDA Boxed Warning

• Coadministration with certain nonsedating antihistamines, sedative hypnotics, antiarrhythmics, or ergot alkaloids may cause potentially serious or life-threatening adverse events.

Action

Inhibits human immunodeficiency virus (HIV) nonnucleoside reverse transcriptase by binding directly to reverse transcriptase and blocking RNA-dependent and DNA-dependent polymerase activity

Availability

Capsules: 100 mg

Oral solution: 80 mg/ml

⊘Indications and dosages

➣ HIV

Adults: Initially, 300 mg P.O. b.i.d.; increase by 100 mg b.i.d. q 2 to 3 days, up to a usual maintenance dosage of 600 mg b.i.d.

Children ages 2 and older: 400 mg/m² b.i.d., not to exceed 600 mg b.i.d. Start with 250 mg/m² to minimize nausea.

Off-label uses

• Chronic hepatitis B

Contraindications

• Hypersensitivity to drug or its components
• Concurrent use of astemizole and terfenadine (not available in U.S.), amiodarone, bepridil, cisapride, dihydroergotamine, ergonovine, ergotamine, flecainide, methylergonovine, midazolam, pimozide, propafenone, quinidine, or triazolam

Precautions

Use cautiously in:
• hepatic disease, diabetes mellitus, hemophilia types A and B
• pregnant or breastfeeding patients.

Administration

• Give with meals to increase absorption.
• Mix oral solution with chocolate milk or liquid nutritional supplement to mask taste.
• Know that drug is usually given with other antiretrovirals.
☞ Don't give concurrently with amiodarone, astemizole, bepridil, cisapride, dihydroergotamine, ergonovine, ergotamine, flecainide, methylergonovine, midazolam, pimozide, propafenone, quinidine, terfenadine, or triazolam. Serious interactions may occur.

Route	Onset	Peak	Duration
P.O.	Rapid	2-4 hr	Unknown

Adverse reactions

CNS: headache, dizziness, depression, insomnia, drowsiness, asthenia, paresthesia, syncope, malaise

CV: vasodilation

EENT: pharyngitis

GI: nausea, vomiting, diarrhea, constipation, dyspepsia, flatulence, abdominal pain, anorexia

Musculoskeletal: myalgia

Skin: diaphoresis

Other: abnormal taste, fever, pain

Interactions

Drug-drug. Amiodarone, bepridil, cisapride, flecainide, midazolam, pimozide, propafenone, quinidine, triazolam: inhibited metabolism of these drugs, leading to life-threatening reactions (such as arrhythmias, prolonged sedation, and respiratory depression)

Amitriptyline, anticoagulants, atovaquone, carbamazepine, clozapine, cyclosporine, desipramine, diltiazem, disopyramide, divalproex, dofetilide, dronabinol, ethinyl estradiol, lamotrigine, phenytoin, sulfamethoxazole, theophylline, zidovudine: increased risk of toxicity of these drugs

Amprenavir: increased amprenavir blood level

Astemizole, cisapride, encainide: increased risk of arrhythmias

Atorvastatin, cerivastatin, lovastatin, simvastatin, terfenadine: increased blood levels of these drugs, increased risk of rhabdomyolysis

Barbiturates, nevirapine, phenytoin, rifamycins: decreased ritonavir blood level

Bupropion: increased risk of seizures

Clarithromycin, efavirenz: increased blood levels of both drugs

Dihydroergotamine, ergonovine, ergotamine, methylergonovine: ergot toxicity

Fluconazole: increased ritonavir blood level

Drug-diagnostic tests. Alanine aminotransferase, aspartate aminotransferase, cholesterol, creatine kinase, gamma-glutamyltransferase, triglycerides, uric acid: increased levels

Hematocrit, hemoglobin, neutrophils, red blood cells, white blood cells: decreased levels

Drug-herbs. St. John's wort: decreased ritonavir blood level

Patient monitoring

• Monitor CBC, liver function tests, electrolyte levels, and lipid panel.
• Assess neurologic status closely. Stay alert for depression.
• Monitor vital signs and watch for syncope.
• Closely monitor nutritional and hydration status.

Patient teaching

• Advise patient to take with meals to increase absorption.
• Encourage patient to mix oral solution with chocolate milk or liquid nutritional supplement to mask taste.
• Tell patient drug may cause numbness, tingling, weakness, and other CNS effects that increase his injury risk. Urge him to use appropriate safety precautions.
• Instruct patient to report depression.
• Tell female patient not to breastfeed because of risk of serious adverse reactions and possible HIV transmission to infant.
• As appropriate, review all other significant adverse reactions and interactions, especially those related to the drugs, tests, and herbs mentioned above.

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Norvir®

Ritonavir, see there