There are many drug interactions with antihypertensive agents and some of these are highly significant. Patients with hypertension frequently take multiple medications and may be at increased risk for drug interactions. Nearly every elderly patient with multiple medical problems will have the potential for one drug interaction in their regimen. These drug interactions can lead to morbidity or even mortality if appropriate steps are not taken to minimize this risk. Drug interactions may occur due to pharmacokinetic (i.e., absorption, distribution, metabolism, elimination) or pharmacodynamic interactions. Physicians and pharmacists must remain vigilant in their monitoring of potential drug interactions and make appropriate dosage or therapy adjustments.