HIV Antiretroviral Treatments
Antiretroviral drugs (ARD) prevent
HIV entry into the host cell and/or its replication.
Entry inhibitors are co-receptor antagonists block the co-receptor from binding with the HIV virion.
Fusion inhibitors prevent fusion of the HIV virion with the host cell membrane.
Reverse transcriptase inhibitors block the reverse transcription of RNA to dsDNA, aka, the provirus.
Integrase inhibitors prevent integration of the provirus with the host's genome.
protease inhibitors prevent the synthesis of viral enzymes.
Drugs that inhibit HIV entry
Maraviroc blocks the chemokine receptor CCR5, to which R5 strains of HIV use as co-receptors; it is associated with GI problems, musculoskeletal pain, and hepatotoxicity.
Enfuvirtide binds the HIV envelope glycoprotein 41, preventing its fusion with the host cell; it is administered subcutaneously, and is associated with hypersensitivity; it is also associated with increased risk of bacterial pneumonia.
Rategravir, Dolutegravir, & Elvitegravir
These are associated with nausea, dizziness, and fatigue, and are used in combination treatments.
Nucleoside Reverse Transcriptase Inhibitors
As a group, these are often associated with lactic acidosis; individuals with renal insufficiency require reduced dosages.
Abacavir; associated with severe hypersensitivity reactions.
Didanosine; presents complications in patients with pancreatitis, and may induce neuropathy or negatively affect the GI system, liver, or CNS.
Emtricitabine; contraindicated in pregnancy and children, individuals with hepatic or renal dysfunction; it is associated with GI problems, headache, and hyperpigmentation.
Lamivudine; associated with GI problems, headache, and insomnia (note that it is also used in Hepatitis B treatment).
Stavudine; this drug is especially associated with lactic acidosis, but also peripheral neuropathy and pancreatitis.
Zidovudine (formerly AZT); associated with anemia and neutropenia (due to bone marrow suppression).
Tenofovir; associated with GI problems, headache, weakness, and renal toxicity; works on nucleotides (not nucleosides).
Non-nucleoside Reverse Transcriptase Inhibitors
Efavirenz; associated with CNS dysfunction, rash, and increased plasma cholesterol.
Etravirine; this is a newer drug, with known drug interactions. It is also associated with rash, nausea, and other GI problems.
Nevirapine; some authors report this drug is particularly useful to prevent HIV transmission to the neonate; it is associated with hypersensitivity reactions.
As a group, they are associated with carbohydrate and lipid metabolism disorders.
Ritonavir is commonly prescribed because it inhibits drug metabolism, which enhances the actions of other protease inhibitors; thus, it is prescribed in conjunction with several of the following:
Atazanavir; when using this drug, patients must avoid antacids for 12 hours; it is also associated with GI problems, peripheral neuropathy, rash, prolonged PR interval, and liver effects.
Darunavir; associated with GI problems, rash, liver effects; additionally, beware of sulfonamide allergy.
Forsamprenavir is contraindicated in pregnancy and children; it is associated with GI problems and rash.
Nelfinavir is known to have multiple drug interactions, but, some recommend it during pregnancy.
Saquinavir is associated with nausea, GI problems, and rhinitis.
Tipranavir is associated with liver damage and brain bleeding.
Indinavir; associated with nausea, GI problems, thrombocytopenia, nephrolithiasis, and insulin resistance; it is not a drug of first choice.
Highly Active Antiretroviral Therapy, aka, combined antiretroviral therapy, is a program in which three or more antiretroviral drugs are used together.
Combination medicines that comprise drugs from multiple classes, may make this easier for the patient, as only a single pill needs to be taken.
IRIS – Immune Reconstitution Inflammatory Syndrome presents as systemic or local inflammatory reactions that can occur after ART; the inflammation reflects re-activation of the immune system to pre-existing infections.
Cessation of ARDs allows HIV to resume replication.
Pre-exposure prophylaxis (aka, PrEP), can be used to prevent HIV in at-risk individuals; for example, non-infected sexual partners of HIV-positive people.
Currently,
Truvada is commonly prescribed for this purpose; it is a combination of
tenofovir and emtricitabine.
For maximum effectiveness, it needs to be taken daily; studies indicate that it can reduce the risk sexual transmission of HIV by approximately 90%, and the risk of transmission via intravenous drug use by approximately 70%.
Post-exposure prophylaxis (aka, PEP)
If an individual suspects he or she has already been exposed to HIV, PEP must be administered within 72 hours of exposure.
For example, health care workers who've had an accidental needle prick or individuals who have been sexually assaulted can mitigate their risk of HIV infection with PEP.
This treatment comprises administration of 3 or more ARDs daily for 4 weeks, along with HIV testing and precautions against further transmission.
Mother-neonate transmission can be prevented with the use of ARDs, and breastfeeding is discouraged.
— If the mother's
viral load is high near the time of birth, cesarean section is recommended; if the mother's viral load is low, the risks associated with cesarean section likely outweigh the benefits.
