Drug Interactions With Pseudoephedrine
The following sections explain in detail the potentially negative interactions that can occur when pseudoephedrine is combined with any of the drugs listed above.
Combining bromocriptine with pseudoephedrine may increase the risk of serious problems such as high blood pressure, an irregular heart rhythm (arrhythmia), or seizures. If you take bromocriptine, check with your healthcare provider before taking pseudoephedrine.
Taking pseudoephedrine with a cannabinoid drug increases the risk of a rapid heart rate (tachycardia), which can be dangerous. It is probably best to avoid combining pseudoephedrine with a cannabinoid, unless your healthcare provider recommends otherwise.
Carbonic Anhydrase Inhibitors
Carbonic anhydrase inhibitor medications may increase the level of pseudoephedrine in the blood (by decreasing its excretion through the urine). This may increase the risk of pseudoephedrine side effects. If you take a carbonic anhydrase inhibitor, check with your healthcare provider before taking pseudoephedrine.
Iobenguane I 123
Pseudoephedrine may interfere with tests that use iobenguane I 123. You should not take pseudoephedrine for several days before a laboratory test that involves iobenguane I 123 (your healthcare provider will give you more specific instructions).
Monoamine Oxidase Inhibitors (MAOIs)
Taking pseudoephedrine and an MAOI together can cause life-threatening problems. Never take pseudoephedrine with an MAOI or even within two weeks of taking an MAOI.
Pseudoephedrine may increase the risk of a dangerous irregular heart rhythm (arrhythmia) due to a phenothiazine medication. If you are on a phenothiazine medication, check with your healthcare provider before taking pseudoephedrine.