Classifications: antiretroviral agent; protease inhibitor;
; protease inhibitor
Prototype: Saquinavir
Pregnancy Category: B


250 mg, 625 mg tablets; 50 mg/g powder


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.


Treatment of HIV infection in combination with a nucleoside analog.


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 (2–13 y): PO 20–30 mg/kg t.i.d. with food (max: 750 mg/dose)


  • 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.


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.


Absorption: Food increases the amount of drug absorbed. Distribution: >98% protein bound. Metabolism: In the liver (CYP3A). Elimination: Primarily in feces. Half-Life: 3.5–5 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.

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

© 2006-2023 Last Updated On: 01/30/2023 (0)
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