As with all antiretrovirals it is important to take indinavir (Crixivan) as recommended. If doses are missed, blood levels of the drug may fall and lead to the development of resistance.

The recommended dose of indinavir is 800mg three times daily. Indinavir comes in 200, 333 and 400mg capsules. Indinavir is the only anti-HIV drug that needs to be taken three times a day, limiting its appeal for many patients.

A dose of 1000mg three times daily may be recommended if drug level testing indicates that there are low blood levels of the drug, or if it is being taken in combination with a drug that reduces blood levels of indinavir. People with liver damage due to cirrhosis should take 600mg three times daily.

Research into twice-daily indinavir was halted due to poor results^[1]. Although some experts believe that this was due to poor adherence in the twice-daily arm, the manufacturer advises that anyone taking indinavir twice daily as their only protease inhibitor should move to the three times daily regimen.

A twice-daily regimen including 667mg indinavir boosted with 100mg ritonavir (Norvir) produces similar maximal blood concentrations to 800mg indinavir taken three times a day. The boosted combination also brought about a six-fold increase in the minimal blood drug concentration^[2]. However, there is some evidence that adding ritonavir increases the incidence of side-effects such as kidney stones, and the best doses for ritonavir and indinavir are unclear^[3][4]. Other dose combinations that may be effective with low rates of side-effects include 400mg indinavir boosted by 100mg ritonavir twice a day, but further studies are required^[5].

Indinavir is best absorbed into the body when it is taken with water on an empty stomach. Ideally, each indinavir dose should be taken at least one hour before or at least two hours after eating a meal. However, a low-fat light snack, such as toast and jam without butter or margarine, corn flakes and skimmed milk or orange juice will not interfere significantly with its absorption. Grapefruit juice delays the absorption of indinavir and should be avoided.

People taking indinavir should drink at least 1.5l of fluid a day to reduce the risk of kidney problems. The extra water should be taken with each indinavir dose and before going to bed.

Indinavir capsules are sensitive to moisture and should always be kept in the original bottle, which includes a desiccant to absorb moisture.

A lipid-associated form of indinavir is being developed. It is hoped that this form will enable the drug to reach higher levels within the lymph tissue, leading to better control of HIV. It is predicted that this form of indinavir will only need to be taken every four days^[6].