Hawthorn Interactions

Hawthorn (Crataegus) has mild vasodilatory and positive inotropic effects that can additively lower blood pressure and slow heart rate when combined with metoprolol, increasing the risk of hypotension, bradycardia, dizziness, or syncope. The interaction is pharmacodynamic, not metabolic, so spacing the doses does not prevent it.

Hawthorn (Crataegus) has digoxin-like positive inotropic activity, may modulate P-glycoprotein efflux, and can interfere with serum digoxin immunoassays. Concurrent use raises the risk of additive cardiac effects and erroneous digoxin level readings even though formal pharmacokinetic studies show little change in digoxin AUC.

Hawthorn produces modest blood pressure lowering (roughly 5 to 11 mmHg systolic in clinical trials) through vasodilation and mild ACE-like activity. Combined with losartan, the additive effect could occasionally cause hypotension or dizziness, particularly in people on multiple antihypertensives or those starting hawthorn at high doses.

Hawthorn (Crataegus) flavonoids improve myocardial contractility and coronary blood flow through mild ACE inhibition and vasodilation, while CoQ10 supports cardiac ATP production in the electron transport chain. Together they address both the mechanical and metabolic demands of the failing or stressed heart.

Aged garlic extract lowers blood pressure through endothelial nitric oxide release, mild ACE inhibition, and antioxidant effects, while hawthorn flavonoids provide vasodilation, mild positive inotropy, and improved coronary flow. Together they act on complementary aspects of vascular tone and cardiac function in mild hypertension.