Nelfinavir Mesylate

A to Z Drug Facts

 Action Inhibits human immunodeficiency virus (HIV) protease, the enzyme required to form functional proteins in HIV-infected cells.

 Indications Treatment of HIV infection. May be given in combination with nucleoside analogues (eg, zidovudine) or as monotherapy.

 Contraindications Hypersensitivity to nelfinavir or any component of the product. Concomitant therapy with amiodarone, astemizole, cisapride, ergot-derivatives, quinidine, rifampin and terfenadine. Concurrent therapy with alprazolam, clorazepate, diazepam, estazolam, flurazepam, midazolam, triazolam and zolpidem.

 Route/Dosage

ADULTS & CHILDREN > 13 YR: PO 750 mg tid in combination with nucleoside analogs. CHILDREN 2 to 13 YR: PO 20 to 30 mg/kg/dose tid.

 Interactions

Amiodarone, astemizole, cisapride, quinidine, rifabutin, terfenadine: Nelfinavir may elevate blood levels of these drugs, which may increase the risk of arrhythmias or other potential serious adverse effects. Alprazolam, clorazepate, diazepam, estazolam, flurazepam, midazolam, triazolam, zolpidem: Nelfinavir may increase blood levels of these drugs, which may produce extreme sedation and respiratory depression. Do not coadminister. Rifampin: May decrease plasma concentrations of nelfinavir. Oral contraceptives: Concentrations of ethinyl estradiol, a component of oral contraceptives, may be reduced. Indinavir: Nelfinavir may increase indinavir blood levels. Indinavir, retonavir: May increase nelfinavir plasma concentrations. Carbamazepine, phenobarbital, phenytoin: May decrease nelfinavir plasma concentrations.

 Lab Test Interferences None well documented.

 Adverse Reactions

CNS: Headache; paresthesia; dizziness; insomnia; somnolence; anxiety; depression; seizures; emotional lability; hyperkinesis. DERM: Rash; pruritus; sweating; urticaria. EENT: Pharyngitis; rhinitis; sinusitus. GI: Anorexia; diarrhea; dyspepsia; flatulence; nausea; vomiting; abdominal pain; pancreatitis; bleeding; mouth ulcerations. GU: Sexual dysfunction; kidney calculus. HEPA: Hepatitis. HEMA: Anemia; leukopenia; thrombocytopenia. META: Increased alkaline phosphotase; liver function tests; creatinine phosphokinase; hyperlipidemia. RESP: Dyspnea. OTHER: Asthenia; fever; myalgia; back pain; malaise; arthralgia; myasthenia; myopathy.

 Precautions

Pregnancy: Category B. Lactation: Undetermined. HIV-infected mothers should not breastfeed their infants. Children: Safety and efficacy not established for children < 2 yr. Hepatic function impairment: Use caution; decreased nelfinavir clearance may occur. Diabetes: New onset diabetes and exacerbation of pre-existing diabetes mellitus has been reported in postmarking surveillance. Hemophilia: There have been reports of increased bleeding, including skin hematomas and hemarthrosis in patients with hemophilia type A and B treated with protease inhibitors. A causal relationship has not been established. Phenylketonuria: Nelfinavir powder contains 11.2 mg phenylalanine per gm of powder.

 Administration/Storage

• Administer with food.
• The oral powder may be mixed with a small amount of water, milk, formula, soy formula, soy milk or dietary supplement (eg, Ensure). Use within 6 hr of mixing.
• Do not mix oral powder with acidic food or juice (eg, orange juice, apple juice, apple sauce) because of bitter taste.
• Store tablets and powder at room temperature.

 Assessment/Interventions

• Obtain patient history, including drug history and any known allergies. Note hepatic function impairment, phenylketonuria or diabetes.
• Obtain baseline triglycerides, SGOT, SGPT, GGT, CPK, blood sugar, and uric acid. Monitor periodically during treatment.
• Monitor HCT, HGB, WBC, and differential. Note any significant change.
• Monitor patient for diarrhea, the most frequent side effect. This may be treated with otc antidiarrheals such as loperamide.

 Patient/Family Education

• Advise patient to take medication exactly as prescribed, including taking each dose with food to increase absorption.
• Warn patient not to alter dose or discontinue the medication without consulting the health care provider.
• Advise patient that if a dose is missed, it should be taken as soon as possible and then return to normal dose. However, if a dose is skipped, the patient should not double the next dose.
• Instruct patient not to take any other medications, including otc medications, without checking with their health care provider. This medication interacts with a wide range of all types of medications.
• Explain that the patient will be required to have frequent follow-up blood and urine tests during the course of treatment and to keep appointments.
• Inform patient that this medication is not a cure for HIV infection and that the patient may continue to acquire secondary illnesses associated with the disease.
• Emphasize to patient, family, and significant others that this medication does not reduce the risk of transmitting HIV to others through sexual contact or blood contamination.
• Inform patient that diarrhea is the most common adverse effect and that it can usually be controlled by otc antidiarrheals such as loperamide.
• Inform patient to report serious or bothersome side effects to the health care provider.
• Explain that the long-term effects of this medication are not known at this time.
• Inform patients taking oral contraceptives that alternate or additional contraceptive measures should be used during therapy with nelfinavir.

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Copyright © 2003 Facts and Comparisons
David S. Tatro
A to Z Drug Facts