Inclusion Criteria

Concurrent Medication:

Allowed:

• Local treatment for Kaposi's sarcoma.
• Prophylactic treatment for opportunistic infections.

Patients must have:

• HIV-1 infection.
• CD4+ lymphocyte count >= 200 cells/microliter within 14 days prior to study drug administration.
• No active diagnosis of AIDS (other than visceral Kaposi's sarcoma) according to the 1993 Centers for Disease Control and Prevention (CDC) AIDS surveillance definition.

Prior Medication:

Allowed:

Local treatment for Kaposi's sarcoma.

Exclusion Criteria

Co-existing Condition:

Patients with the following symptoms and conditions are excluded:

Malabsorption syndrome or other GI dysfunction which may interfere with drug absorption.

Concurrent Medication:

Excluded:

• Medications that cannot be withheld for 48 hours (24 hours for antiretrovirals) prior to study drug administration and until 12 hours after study drug administration on each dosing day.
• Immunomodulators, such as systemic corticosteroids, interleukins and interferons.
• Cytotoxic chemotherapeutic agents.
• Acute treatment for opportunistic infections.

Concurrent Treatment:

Excluded:

Radiation therapy.

Patients with the following prior conditions are excluded:

• Documented history of alcoholism.
• History of clinically relevant hepatitis or pancreatitis within 6 months prior to study drug administration.
• History of hypersensitivity, anaphylactic, or idiosyncratic reaction to nucleoside analogs.
• Participation in another research study within the past month.

Prior Medication:

Excluded:

• Cytotoxic chemotherapeutic agents within six weeks prior to study drug administration.
• Immunomodulating agents within six weeks prior to study drug administration.
• Treatment with the following within 2 weeks prior to study drug administration:
• acyclovir, carbamazepine, chloramphenicol, ganciclovir, phenytoin, rifampin, sodium valproate, or valacyclovir.

Prior Treatment:

Excluded:

Radiation therapy within 6 weeks prior to study drug administration.

1. Regular weekly alcohol intake of more than 21 units (a unit is equal to 1/2 pint beer or 1 glass of wine or 1 oz of liquor).

• Recent change in normal pattern of alcohol usage (e.g., prolonged use followed by > one month abstinence).
• Total abstinence from alcohol use.
• Positive breath alcohol test upon arrival at the study center prior to any dosing day.