Drug Interaction Report

MONITOR: Concomitant use of ashwagandha with other agents that are known to induce hepatotoxicity may theoretically increase the risk of hepatotoxicity. There are case reports of adverse effects on liver functions associated with ashwagandha use. In a case report, a 20-year-old man in Japan developed liver dysfunction and hyperbilirubinemia after using ashwagandha in combination with multiple antianxiety drugs. In additional case reports, three men and two women, age range 21 to 62 years who reportedly took supplements containing 450 to 1,350 mg ashwagandha daily over the course of one week to four months when signs of liver injury, such as jaundice, pruritus, nausea, lethargy, abdominal discomfort, and hyperbilirubinemia, appeared.

MANAGEMENT: Liver function tests should be monitored, and patients should be advised to report any symptoms such as abdominal pain, jaundice, dark urine, light stools, fever, or unusual fatigue.

GENERALLY AVOID: Moderate-to-high dietary intake of potassium can cause hyperkalemia in some patients who are using angiotensin converting enzyme (ACE) inhibitors. In some cases, affected patients were using a potassium-rich salt substitute. ACE inhibitors can promote hyperkalemia through inhibition of the renin-aldosterone-angiotensin (RAA) system.

ADJUST DOSING INTERVAL: Administration with food decreased the biotransformation of perindopril to its active metabolite, perindoprilat, resulting in a decrease of perindoprilat bioavailability by 35% and a reduction in the plasma ACE inhibition curve of approximately 20%. When administered as part of a combination product with amlodipine and taken with food, perindopril and perindoprilat absorption rates have decreased by 18% and 14%, respectively, versus fasting. No effect of food on the extent of unmetabolized perindopril absorption has been observed.

MANAGEMENT: It is recommended that patients who are taking ACE inhibitors be advised to avoid moderately high or high potassium dietary intake. Particular attention should be paid to the potassium content of salt substitutes. Some authorities recommend administering perindopril before a meal, preferably in the morning. According to the prescribing information, the combination product containing perindopril and amlodipine may be taken with or without food.