Objective: Herb-drug interactions of ashwagandha, an immunomodulatory agent along with ritonavir were studied in the context of their possible concomitant usage. This study investigates the possibility of pharmacokinetic interaction and also its effect on the toxicity effects between ritonavir and ashwagandha. Methods: Single and multiple oral doses of ritonavir (30 mg/kg) and in combination with ashwagandha (300 mg/kg) in adult wistar rats were performed for one and nine days on two different groups (n = 6) respectively. PK parameters, CBP, SGPT, SGOT and serum creatinine levels of different groups were measured.
Results: Repeated oral administration of ashwagandha along with ritonavir caused the decrease in the plasma concentration of ritonavir 22.74 ± 1.61 (μg/h), increased the RBC number 4.98 ± 0.04 (m/cmm) and has significantly decreased the levels of SGOT and SGPT 24.66 ± 1.75 (U/L), 10.83 ± 1.47 (U/L) against ritonavir treated rats. The ritonavir plasma concentrations decreased significantly both in single and multiple doses groups of ashwagandha. Ashwagandha protected the deleterious effects caused by ritonavir on the blood cells. It has significantly decreased the SGOT and SGPT levels when compared to ritonavir treated rats. But, it did not decrease the serum creatinine levels.
Conclusion: Using ashwagandha along with ritonavir has no deleterious effects on the major organ systems. It also increases the absorption of ritonavir into the systemic circulation.