Included among the responsibilities of a Maryland pharmacist is the duty to ensure that the medication provided to a patient does not negatively interact with the patient’s other prescriptions. Prescription medications contain powerful drugs and many prescription medications should not be taken with other prescription medication or even over-the-counter medications.
There are several types of drug interactions, including pharmacodynamic and pharmacokinetic interactions. A pharmacodynamic interaction occurs when two medications that react with the same receptor site are taken at the same time. Pharmacodynamic interactions result in the ingested medications having a greater (synergistic) or decreased (antagonistic) effect, depending on the specific medications involved. Pharmacodynamic interactions can be fatal.
Pharmacokinetic interactions occur when one drug affects the body’s ability to absorb, metabolize, distribute, or eliminate another medication. For example, calcium can bind to some medications, reducing their absorption. Thus, patients are advised not to take the HIV medication Tivicay at the same time as Tums because the calcium in Tums can lower the amount Tivicay that is absorbed into the patient’s system. In this situation, doctors suggest patients take the two medications at staggered times throughout the day.