Reverse-transcriptase inhibitor

Reverse-transcriptase inhibitors (RTIs) are a class of antiretroviral drugs used to treat HIV and hepatitis B viral infections. They inhibit the activity of reverse transcriptase, a viral DNA polymerase that is required for replication of HIV and other retroviruses.

Mechanism of Action

Reverse-transcriptase inhibitors work by inhibiting the action of reverse transcriptase, an enzyme that converts viral RNA into DNA. This process, known as reverse transcription, is necessary for the virus to replicate within the host cell. By blocking this process, RTIs prevent the virus from multiplying and reduce the amount of virus in the body.

Types of RTIs

There are two main types of reverse-transcriptase inhibitors: nucleoside reverse transcriptase inhibitors (NRTIs) and non-nucleoside reverse transcriptase inhibitors (NNRTIs).

Nucleoside Reverse Transcriptase Inhibitors (NRTIs)

Nucleoside Reverse Transcriptase Inhibitors (NRTIs) are analogs of the normal nucleosides needed for DNA synthesis. They compete with the natural nucleosides, leading to premature termination of the DNA chain.

Examples of NRTIs include:

• Zidovudine (AZT)
• Lamivudine (3TC)
• Abacavir (ABC)

Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs)

Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs) bind to a different site on the reverse transcriptase enzyme than NRTIs. They do not compete with nucleosides, but inhibit the action of the enzyme directly.

Examples of NNRTIs include:

• Nevirapine (NVP)
• Efavirenz (EFV)
• Etravirine (ETR)

Side Effects

Like all medications, reverse-transcriptase inhibitors can cause side effects. Common side effects include nausea, vomiting, and diarrhea. Some RTIs can also cause more serious side effects, such as liver damage or an increased risk of heart attack.

See Also

• Antiretroviral therapy
• HIV/AIDS
• Hepatitis B