DELAVIRDINE MESYLATE

DELAVIRDINE MESYLATe (del-a-vir'deen) Rescriptor Classifications: antiviral; nonnucleoside reverse transcriptase inhibitor (nnrti); Therapeutic: antiviral; nnrti Prototype: Efavirenz Pregnancy Category: C

Availability

100 mg tablets

Action

Nonnucleoside reverse transcriptase inhibitor (NNRTI) of HIV-1 binds directly to reverse transcriptase (RT) and disrupts RNA- and DNA-dependent DNA polymerase activities.

Therapeutic Effect

It prevents replication of the HIV-1 virus. HIV-2 RT and human DNA polymerases such as polymerases alpha, gamma, and delta are NOT inhibited by delavirdine. Resistant strains appear rapidly.

Uses

Treatment of HIV infection in combination with other antiretroviral agents.

Contraindications

Hypersensitivity to delavirdine; pregnancy (category C); lactation.

Cautious Use

Impaired liver function; achlorhydria.

Route & Dosage

HIV Infection Adult: PO 400 mg t.i.d. Child (≤16 y): PO 400 mg t.i.d.

Administration

Oral

• Disperse in water by adding a single dose to at least 3 oz of water, let stand for a few minutes, then stir to create a uniform suspension just prior to administration.
• Give drug to patients with achlorhydria with an acid beverage such as orange or cranberry juice.
• Store at 20°–25° C (68°–77° F) and protect from high humidity in a tightly closed container.

Adverse Effects (≥1%)

Body as a Whole: Headache, fatigue, allergic reaction, chills, edema, arthralgia. CNS: Abnormal coordination, agitation, amnesia, anxiety, confusion, dizziness. CV: Chest pain, bradycardia, palpitations, postural hypotension, tachycardia. GI: Nausea, vomiting, diarrhea, increased LFTs, abdominal cramps, anorexia, aphthous stomatitis. Hematologic: Neutropenia. Respiratory: Bronchitis, cough, dyspnea. Skin: Rash, pruritus.

Interactions

Drug: antacids, h₂-receptor antagonists decrease absorption; didanosine and delavirdine should be taken 1 h apart to avoid decreased delavirdine levels; clarithromycin, fluoxetine, ketoconazole may increase delavirdine levels; carbamazepine, phenobarbital, phenytoin, rifabutin, rifampin may decrease delavirdine levels; delavirdine may increase levels of clarithromycin, indinavir, saquinavir, dapsone, rifabutin, alprazolam, midazolam, triazolam, dihydropyridine, calcium channel blockers (e.g., nifedipine, nicardipine, etc.), quinidine, warfarin. Use with hmg-coa reductase inhibitors may increase the risk of rhabdomyolysis. Use with pimozide may cause cardiac arrhythmias. Use with trazodone may increase trazodone levels. Use with inhaled fluticasone may increase fluticasone levels. Use with hypnotics, alprazolam, midazolam, triazolam can cause respiratory depression. Herbal: St. John's wort may decrease antiretroviral activity.

Pharmacokinetics

Absorption: Rapidly from GI tract, 80% reaches systemic circulation. Peak: 1 h. Distribution: 98% protein bound. Metabolism: In the liver by CYP3A4. Elimination: Half in urine, 44% in feces. Half-Life: 2–11 h.

Nursing Implications

Assessment & Drug Effects

• Therapeutic effectiveness: Indicated by decreased viral load.
• Monitor for and immediately report appearance of a rash, generally within 1–3 wk of starting therapy; rash is usually diffuse, maculopapular, erythematous, and pruritic.

Patient & Family Education

• Take this drug exactly as prescribed. Missed doses increase risk of drug resistance.
• Do not take antacids and delavirdine at the same time; separate by at least 1 h.
• Report all prescription and nonprescription drugs used to physician because of multiple drug interactions.
• Discontinue medication and notify physician if rash is accompanied by any of the following: Fever, blistering, oral lesions, conjunctivitis, swelling, muscle or joint pain.

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Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug