Table 4.

Summary of the factors affecting antiretroviral drug CNS penetrations.

General factors	Pharmacokinetics/pharmacogenetics	Other factors
(i) Blood-Brain barrier (BBB) (ii) Blood-CSF barrier (BCSFB) (iii) Drug transporter	(i) Drug-drug interactions (ii) Drug-herb interactions (iii) Enzyme inhibition/induction (iv) Polymorphism in drug metabolizing enzyme (v) Drug-protein binding  (vi) Molecular weight of the antiretroviral drug	(i) Local cerebral blood flow (ii) Presence of chronic inflammation