The use of a combination ARVs or highly active antiretroviral therapy (HAART) has been a major advance in the treatment of HIV infection. These drugs are classified into four classes according to the mechanisms of inhibition of viral replication (Table 9.2): reverse transcriptase enzyme inhibitors, protease enzyme inhibitors, integrase inhibitors and entry inhibitors.
Many adverse side effects are associated with ARVs and should be looked for during preoperative assessment. They can be divided broadly into four groups:
- Mitochondrial dysfunction: lactic acidosis, hepatic toxicity, pancreatitis, peripheral neuropathy
- Metabolic abnormalities: fat maldistribution and change in body habitus, dyslipidemia, hyperglycemia and insulin resistance, bone disorders e.g. osteoporosis and osteonecrosis
- Bone marrow suppression: anemia, neutropenia and thrombocytopenia
- Allergic reactions: skin rashes and hypersensitivity responses.
Antiretroviral Drugs and Their Side Effects
Table 9.2 anti retroviral drugs and their side effects
|Class||Sub Class||Drugs||Side Effects|
|Reverse transcriptase inhibitors||Nucleoside/nucleotide analogues (NRTIs)||Abacavir (ABC)||Gastrointestinal disturbances, skin rash, myalgia|
|Didanosine (ddI)||Peripheral neuropathy, pancreatitis, gastrointestinal disturbances|
|Lamivudine (3TC)||Peripheral neuropathy, skin rash, gastrointestinal disturbances|
|Stavudine (d4T)||Peripheral neuropathy, pancreatitis|
|Zidovudine (AZT, ZDV)||Anemia, neutropenia, pancytopenia, headache, neuropathy, myopathy|
|Non-nucleotide reverse transcriptase Inhibitors (NNRTIs)|
|Efavirenz (EFV)||Skin rash, GI disturbances, increased liver enzymes|
|Nevirapine (NVP)||GI disturbances, increased liver enzymes, skin rash, P-450 enzyme induction|
|Protease inhibitors (PIs)||Atazanavir||GI disturbances, renal failure, hyperglycemia, skin rash, nephrolithiasis, unusual distribution of fat, inhibits cytochrome P-450|
|Nelfinavir (NFV)||GI disturbances, hyper-glycemia, lipodystrophy, inhibits cytochrome P-450|
|Ritonavir (RTV)||GI disturbances, hyperglycemia, increased liver enzymes, lipo-dystrophy, inhibits cytochrome P-450|
|Saquinavir (SQV)||GI disturbances, hyper- glycemia, lipodystrophy, inhibits cytochrome P-450|
|Amprenavir (APV)||Skin rash, inhibits cytochrome P-450|
Adherence to antiretroviral therapy is of paramount importance, with adherence levels of below 95% being associated with increases in viral load and drug resistance. This naturally has implications for interruption of ARV therapy due to perioperative fasting. Fasting times should be kept to an absolute minimum.