Several different classes of human immunodeficiency virus (HIV) medications are on the market to treat patients infected with this virus. These include reverse transcriptase inhibitors, protease inhibitors, and fusion inhibitors. A doctor will determine which HIV drugs are most appropriate for the patient after a thorough evaluation and discussion with the patient about the goals of treatment. Since it is not possible to eradicate the virus from the body, the purpose of treatment is to suppress replication to prevent the onset of acquired immune deficiency syndrome (AIDS). This will also prevent the development of complications in patients with advanced HIV infections.
All HIV drugs are active at some stage of viral replication to prevent the virus from reproducing itself in the body. Some act by preventing the virus from entering and hijacking a cell with its genetic material. Others will allow the virus to enter cells, but create stumbling blocks when it tries to reproduce. The virus will mistake the medication as part of its genetic code, and will create faulty replicas with inserts from the medication.
There are several kinds of reverse transcriptase inhibitors. The “nukes” are nucleoside or nucleotide reverse transcriptase inhibitors (NSTIs and NRTIs). These medications interfere with the reverse transcriptase enzyme the virus needs to replicate itself. “Non-nukes,” or non-nucleoside reverse transcriptase inhibitors (NNRTIs), are another example. The effectiveness of the medication can depend on the type of HIV a patient has; the virus comes in several subtypes that tend to be endemic in different regions.
Protease inhibitors interfere with protease, another enzyme the virus needs to make copies of itself, while fusion inhibitors, or entry inhibitors, prevent HIV from entering cells at all. These HIV drugs don't give the virus a chance to start replicating by maintaining a hostile environment inside the body. Another group of HIV drugs known as integrase inhibitors also makes it difficult for HIV to enter and bond with cells to prevent it from colonizing the cells and increasing the patient's viral load.
In anti-retroviral therapy for HIV, a doctor usually prescribes drugs from two different classes to target the virus from multiple angles. Patients need to adhere to the treatment regimen. Periodically it may be necessary to adjust dosages to meet the patient's changing medical needs. Another concern with HIV drugs is the issue of coinfections like tuberculosis and hepatitis C, which may complicate treatment. These infections may necessitate changes to a medication regimen or more careful monitoring.