To assess the tolerability and safety of OPC-14117. To evaluate effects of OPC-14117 on cognitive function, quality of life, and activities of daily living.

Patients receive OPC-14117 or placebo bid for 12 weeks, followed by 12 weeks of open label therapy.

Inclusion Criteria

Patients must have:

• HIV seropositivity.
• Cognitive impairment.

Prior Medication:

Allowed:

• Prior OPC-14117 other than on the current study.
• Antiretroviral therapy if stable for 6 weeks prior to study entry (12 weeks for stavudine).

Exclusion Criteria

Co-existing Condition:

Patients with the following symptoms or conditions are excluded:

• Current opportunistic CNS infection (i.e., toxoplasmosis or cryptococcal meningitis).
• Severe pre-morbid psychiatric illness including schizophrenia and major depression that would interfere with protocol compliance.
• CNS neoplasms.
• Any other clinically significant condition or laboratory abnormality that would interfere with ability to participate on study.
• Current participation in other drug studies.

Patients with the following prior conditions are excluded:

• Past history of opportunistic CNS infection (i.e., toxoplasmosis or cryptococcal meningitis).
• History of chronic neurological disorders such as serious head injury, documented stroke, multiple sclerosis, uncontrolled epilepsy, Tourette's syndrome, and other neurodegenerative processes such as Huntington's disease.
• History of adverse reaction / allergy to OPC-14117.
• Prior participation on this study.

Prior Medication:

Excluded:

• Other investigational drugs within the past 30 days. Alcoholism within past 6 months (more than 2 drinks daily).