Dosing and uses of Viracept (nelfinavir)
Adult dosage forms and strengths
oral powder for suspension
- 50mg/1g scoopful
tablet
- 250mg
- 625mg
HIV Infection
750 mg PO q8hr, Or
1250 mg PO q12hr
Renal Impairment
Dose adjustment not necessary
Hepatic Impairment
Mild impairment (Child-Pugh class A): Dose adjustment not necessary
Severe impairment (Child-Pugh Class B or C): Not recommended
Pediatric dosage forms and strengths
oral powder for suspension
- 50mg/1g scoopful
tablet
- 250mg
- 625mg
HIV Infection
<2 years: Saftey and efficacy not established
2-13 years: 45-55 mg/kg PO q12hr, OR 25-35 mg/kg PO q8hr
Not to exceed adult dose of 2,500 mg/day (q12hr dosing) or 1,875 mg/day (q8hr dosing)
Adolescents: 1,250 mg PO q12hr, OR 750 mg PO q8hr
Also see Administration
Viracept (nelfinavir) adverse (side) effects
>10%
Diarrhea (14-20%)
1-10%
Nausea (3-7%)
Flatulence (1-5%)
Abdominal pain (1%)
Anemia (1%)
Allergic reaction (1%)
Impaired concentration (1%)
Lipodystrophy (1%)
Metabolic acidosis (1%)
Rash (1-3%)
Leukopenia (1%)
Thrombocytopenia (1%)
Weakness (1%)
<1%
QTc prolongation
Torsades de pointes
Diabetes mellitus, new onset and exacerbation
Hyperglycemia
Warnings
Contraindications
Hypersensitivity
Coadministration with major CYP3A4 substrates and/or inducers
Drugs that are contraindicated with nelfinavir include alpha1-adrenoreptor agonists (eg, alfuzosin), antiarrhythmics (amiodarone, bepridil, flecainide, propafenone, quinidine), rifampin, voriconazole, ergot derivatives (dihydroergotamine, ergonovine, ergotamine, methylergonovine), cisapride, St. John’s wort, lovastatin, simvastatin, lurasidone, pimozide, sildenafil (when used for PAH), midazolam, and triazolam
Cautions
Risk to pregnant/ pediatric pts: EMS (ethyl methanesulfonate) impurity shown to be teratogenic, mutagenic & carcinogenic in animal studies
Oral powder contains 11.2 mg of phenylalanine per gram of powder
Risk of immune reconstitution syndrome if used in combination with other antiretroviral drugs
Caution in patients with hemophilia A or B (risk of bleeding); increased bleeding, including spontaneous skin hematomas and hemarthrosis reported with protease inhibitors; in more than half of cases, administration of protease inhibitors was continued or reintroduced
Increased risks of fat redistribution, hemolytic anemia, hyperbilirubinemia if used in combination with other antiretroviral drugs
Increases risk of developing new onset diabetes mellitus; exacerbation of DM & hyperglycemia
Not for use in patients with moderate to- evere hepatic impairment
In pediatrics, drug exposure is highly variable
Pregnancy and lactation
Pregnancy category: B (Antiretroviral Pregnancy Registry established, register pts by calling (800) 258-4263)
Lactation: HIV+ women are advised not to breastfeed
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Viracept (nelfinavir)
Mechanism of action
Protease Inhibitor; inhibits cleavage of Gag-Pol polyprotein precursors, which in turn causes the formation of immature, noninfectious viral particles.
Pharmacokinetics
Absorption: food increases AUC 2-3x
Vd: 2-7 L/kg
Protein Bound: >98%
Metabolism: hepatic via CYP3A4 & CYP2C19; major metabolite has activity comparable to parent drug
Half-life, plasma: 3.5-5 hr
Peak Plasma Time: 2-4 hr
Enzymes Inhibited: CYP3A4
Excretion: Feces: (87%); urine: (1-2%)
Administration
Oral Administration
Mix oral powder with small amount of water, milk, formula or dietary supplement and consume entire dose
Do not mix with acidic food or juice
If not consumed immediately, refrigerate no more than 6 hr
May use crushed 250 mg tablets instead of oral powder
Take all doses with high-fat meals
