Drug – Drug Interactions Between Newer Anti- Retroviral Drugs And Anti Epileptics - A Review

Drug – Drug Interactions (DDIs) are the leading cause of drug toxicity and emergence of drug resistance, ultimately leading to increased burden in People Living with Human Immunodeficiency Virus (PLHIV). On an average 55 % of people on Anti Retroviral Therapy (ARVs) are co-administered with Anti Epileptic Drugs (AEDs). The introduction of newer anti-retroviral drugs such as dolutegravir, bictegravir, emtricitabine, doravirine are proven to have less side effects, high tolerability and effective decrease in the viral load, but the risk of DDIs still stands to be high. This review briefly describes about the pharmacokinetic properties of dolutegravir, bictegravir, emtricitabine, doravirine, mechanism of interaction between the above mentioned ARVs and AEDs, effect of DDIs on ARVs, effect of DDIs on interacting AEDs, outcome of DDIs and possible management of DDIs. The pharmacokinetic type of DDIs was observed between the ARVs and AEDs. The majority of DDIs were found affecting the metabolism and the absorption of the drugs. UGT1A1, CYP 3A are the two important classes of metabolic enzymes involved in the DDIs and p- glycoprotein (P-gp) is the transporter involved in the DDIs affecting the absorption. Significant interactions have been found in between the above mentioned newer ARV’s with carbamazepine, oxcarbazepine, phenytoin and phenobarbitol.

Use of phenytoin for treatment of tacrolimus toxicity with superimposed sepsis

A 40-year-old woman with a history of chronic graft-versus-host-disease on immunosuppression with tacrolimus presented to the hospital with somnolence, confusion and muscle cramps over a few days. She was found to have hypertension, hyperglycaemia and acute kidney injury with an elevated blood tacrolimus level of greater than 120 ng/mL (reference range 5–15 ng/mL). Discontinuation of tacrolimus with concomitant administration of intravenous phenytoin led to the successful reduction of elevated tacrolimus concentrations and the resolution of her symptoms. Tacrolimus is metabolised by the cytochrome P (CYP) 450 3A enzyme system, and utilisation of CYP 3A inducers to accelerate its clearance may be used as a successful therapy to treat tacrolimus toxicity.

Aloe activated P-glycoprotein and CYP 3A: a study on the serum kinetics of aloe and its interaction with cyclosporine in rats

Aloe, the leaf juice ofAloe vera, is a popular functional food worldwide.