SAFETY AND HERB–DRUG INTERACTIONS OF AYURVEDIC MEDHYA DRUGS USED ALONGSIDE PSYCHOTROPIC MEDICINES
Background: Many people with mental and neurological disorders in India use Ayurvedic Medhya drugs alongside conventional psychotropic and antiseizure medicines, often without informing their doctors. Concurrent use creates potential for pharmacokinetic and pharmacodynamic interactions, and some herbal products carry risks of their own. Objective: To review the safety profile of commonly used Medhya herbs and formulations, documented and potential interactions with psychotropic and antiseizure medicines, and practical measures to reduce risk. Methods: Narrative review of clinical reports, pharmacokinetic and in vitro studies, systematic reviews of herb–drug interactions and quality studies of Ayurvedic products. Results: A clinically important interaction has been reported between phenytoin and an Ayurvedic Shankhapushpi preparation, with reduced phenytoin levels and loss of seizure control. Jatamansi increased the protective index of phenytoin in rats, suggesting pharmacodynamic or pharmacokinetic synergy. Bacopa extract and some of its constituents inhibit several human cytochrome P450 enzymes in vitro. Withania somnifera altered the pharmacokinetics of a CYP1A probe drug in rats. Ashwagandha has been associated with rare liver injury and changes in thyroid function, and Centella with rare hepatotoxicity. Piperine, present in Pippali and Trikatu, inhibits CYP3A4 and P-glycoprotein. Some Ayurvedic products contain heavy metals. Additive sedation is a plausible risk when calming herbs are combined with benzodiazepines, antipsychotics or sedating antidepressants. Conclusion: Most Medhya herbs are well tolerated, but interactions with drugs that have narrow therapeutic ranges, particularly antiseizure medicines and lithium, and with sedatives require attention. Systematic history-taking, communication between practitioners, quality-assured products and pharmacovigilance are essential. Clinical interaction studies are urgently needed.
Keywords: herb–drug interactions; Medhya Rasayana; psychotropic drugs; antiepileptic drugs; pharmacovigilance; cytochrome P450; Ashwagandha; Bacopa; Shankhapushpi