You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is Anti-HIV drug combination that should not be used and explain in detail?
Anti-HIV drug combinations that should NOT be used are:

Zidovudine + Stavudine: Pharmacological antagonism (compete for intracellular phosphorylation)
Atazanavir + Indinavir: Additive unconjugated hyperbilirubinemia.
Didanosine/stavudine + Zalcitabine: Additive peripheral neuropathy.
Lamivudine + Zalcitabine: In vitro antagonism.