Other antiviral drugs:
Therapy of HIV Infection: Several distinct classes of drugs are now used to treat HIV infection:
- Nucleoside-Analog Reverse Transcriptase Inhibitors (NRTI).
These drugs inhibit viral RNA-dependent DNA polymerase (reverse
transcriptase) and are incorporated into viral DNA (they are
chain-terminating drugs).
- Zidovudine (AZT = ZDV, Retrovir) first approved in 1987
- Didanosine (ddI, Videx)
- Zalcitabine (ddC, Hivid)
- Stavudine (d4T, Zerit)
- Lamivudine (3TC, Epivir)
- Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs).
In contrast to NRTIs, NNRTIs are not incorporated into viral DNA; they
inhibit HIV replication directly by binding non-competitively to reverse
transcriptase.
- Nevirapine (Viramune)
- Delavirdine (Rescriptor)
- Protease Inhibitors. These drugs are specific for the
HIV-1 protease and competitively inhibit the enzyme, preventing the
maturation of virions capable of infecting other cells.
- Saquinavir (Invirase) first approved in 1995
- Ritonavir (Norvir)
- Indinavir (Crixivan)
- Nelfinavir (Viracept)
Problems
Toxicity. AZT causes anaemia, in fact its toxicity is such that it was
originally rejected as an anti-tumour drug! Interferon and acyclovir can cause
severe nausia and vomiting. Pregnancy is an important contraindication because
of possible teratogenic effects.
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