There are four main types of protease inhibitors. Detailed below are the recommended dosages, interactions with other medicines and the side-effects of protease inhibitors.Indinavir: Eight hundred milligrams of this medicine is recommended either one hour before meals or two hours after meals. Common side-effects include disturbances of the digestive system. Occasionally some people may have headache, blurred vision, rash, dizziness, metallic taste in the mouth and abnormal bleeding or bruising in the body.Indinavir is not recommended with medicines such as rifampicin, cisapride, triazolam and midazolam.Ritonavir: The recommended dose of this medicine is six hundred milligrams twice a day to be taken with meals. This dose is reached by gradually increasing it during fourteen days. The first two days three hundred milligrams of ritonavir is recommended twice day followed by four hundred milligrams twice a day for the next three days. On days six to thirteen, five hundred milligrams is recommended twice a day. Thereafter, six hundred milligrams is recommended twice a day. Ritonavir is often recommended in combination with saquinavir, another protease inhibitor.Common side-effects include nausea, vomiting, diarrhoea, decreased sensation in the limbs, hepatitis and change in the taste sensation. Ritonavir is not recommended with medicines such as cisapride, tranquillisers, quinidine, etc. It can increase the levels of clarithromycin and decrease the levels of zidovudine.Nelfinavir: The recommended dose for adults is seven hundred and fifty milligrams three times a day with meals. Common side-effects include diarrhoea, pain in the abdomen, nausea, rashes and increased gas in the bowels. Medicines such as rifampicin, can reduce the levels of nelfinavir. This medicine is not recommended for use along with tranquillisers, cisapride, etc. It increases the levels of other protease inhibitors such as indinavir and saquinavir.Saquinavir: The recommended dose is six hundred milligrams to be taken three times a day. Some preparations may also be recommended in the dose of twelve hundred milligrams three times a day. Common side-effects include disturbances in the digestive system such as nausea, diarrhoea, pain in the abdomen, headache and indigestion. The levels of saquinavir in the blood are increased by ritonavir and nelfinavir (protease inhibitors) and grapefruit juice. Their levels are reduced by rifampicin, some medicines used for treatment of epilepsy and steroids. It is not recommended along with rifampicin and some tranquillisers. Zidovudine is recommended in almost all combinations of medicines recommended for treatment of HIV infection. This is because its benefits have been observed for a long time and it can enter the brain more effectively than other medicines. HIV not only affects the blood but can also enter the brain. Thus, if a medicine does not enter the brain, it cannot control the infection effectively.*22\288\2*
