NELFINAVIR MESYLATE (nel-fin'a-vir)
Viracept Classifications: antiretroviral agent; protease inhibitor; Therapeutic:antiretroviral; protease inhibitor Prototype: Saquinavir Pregnancy Category: B
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Availability
250 mg, 625 mg tablets; 50 mg/g powder
Action
Inhibits HIV-1 protease, which is responsible for the production of HIV-1 viral particles in an infected individual. Inhibition
of the viral protease prevents the cleavage of the viral polypeptide, resulting in the production of an immature, noninfectious
virus.
Therapeutic Effect
Effectiveness is indicated by decreased viral load.
Uses
Treatment of HIV infection in combination with a nucleoside analog.
Contraindications
Hypersensitivity to nelfinavir; concurrent administration with amiodarone, quinidine, rifampin, triazolam, or midazolam;
lactation. Safety and effectiveness in children <2 y are not established.
Cautious Use
Liver function impairment, hemophilia; pregnancy (category B).
Route & Dosage
HIV Infection Adult: PO 750 mg t.i.d. or 1250 mg (2 x 625 mg) b.i.d. with food Child (213 y): PO 2030 mg/kg t.i.d. with food (max: 750 mg/dose)
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Administration
Oral
- Give with a meal or light snack.
- Oral powder may be mixed with a small amount of water, milk, soy milk, or dietary supplements; liquid should be consumed
immediately. Do not mix oral powder in original container nor with acid food or juice (e.g., orange or apple juice, or applesauce).
- Store at 15°30° C (59°86° F).
Adverse Effects (≥1%)
Body as a Whole: Allergic reactions, back pain, fever, malaise, pain, asthenia, myalgia, arthralgia.
CNS: Headache, anxiety,
depression, dizziness,
insomnia, seizures.
GI: Abdominal pain,
diarrhea, nausea, flatulence, anorexia, dyspepsia,
GI bleeding, hepatitis, vomiting, pancreatitis, increased liver function tests.
Hematologic: Anemia, leukopenia, thrombocytopenia.
Respiratory: Dyspnea, pharyngitis, rhinitis.
Skin: Rash, pruritus, sweating, urticaria.
Interactions
Drug: Other
protease inhibitors,
ketoconazole may increase nelfinavir levels;
rifabutin, rifampin may decrease nelfinavir levels; nelfinavir will decrease
oral contraceptive levels; may increase levels of
atorvastatin, simvastatin; increase risk of
ergotamine toxicity with
dihydroergotamine, ergotamine. Herbal: St. John's wort, garlic may decrease antiretroviral activity.
Pharmacokinetics
Absorption: Food increases the amount of drug absorbed.
Distribution: >98% protein bound.
Metabolism: In the liver (CYP3A).
Elimination: Primarily in feces.
Half-Life: 3.55 h.
Nursing Implications
Assessment & Drug Effects
- Monitor hemophiliacs (type A or B) closely for spontaneous bleeding.
- Monitor carefully patients with hepatic impairment for toxic drug effects.
Patient & Family Education
- Drug must be taken exactly as prescribed. Do not alter dose or discontinue drug without consulting physician.
- Use a barrier contraceptive even if using hormonal contraceptives.
- Be aware that diarrhea is a common adverse effect that can usually be controlled by OTC medications.