Coffee may be such an established ritual in your life that having your morning brew has become as second nature as brushing your teeth. However, when you take over-the-counter (OTC) medications or prescription drugs, it’s important to pause to consider how they may interact with your daily coffee habit.
Most coffee-drug interactions are due to caffeine, the compound that gives coffee its stimulating effects. “Caffeine is rapidly and almost completely absorbed in the gastrointestinal tract, with peak blood concentrations occurring within 15 minutes to two hours after ingestion,” says Emmanuel Osei-Boamah, MD, a primary care physician with Mercy Family Care in Baltimore. That means coffee and medications can interact quickly when taken close together.
However, coffee contains other compounds that can also affect how your body metabolizes certain medications.
1. Antidepressants
Caffeine can interfere with certain antidepressants — in particular, those that are broken down in the liver by the CYP1A2 enzyme (a protein that speeds up chemical reactions). Those include fluvoxamine, a selective serotonin reuptake inhibitor (SSRI), and duloxetine, a serotonin norepinephrine reuptake inhibitor. That’s because CYP1A2 also plays a crucial role in the breakdown of caffeine. So, drugs broken down by this enzyme share the same metabolic pathway and can alter the metabolism of caffeine — and vice versa.
Caffeine can also slow the metabolism of certain SSRIs, including fluoxetine and escitalopram, sometimes boosting their effects as a result. That may enhance the effects of the antidepressant and exacerbate medication symptoms (such as restlessness, appetite changes, and upset stomach).
In addition, combining monoamine oxidase inhibitors (MAOIs) such as tranylcypromine and phenelzine, with too much caffeine can raise the risk of high blood pressure (hypertension).That’s because caffeine can have exaggerated effects in those taking MAOIs, causing hypertension along with tremor (continuous, involuntary shaking or trembling), heart palpitations, anxiety, or poor sleep.
Osei-Boamah recommends separating your coffee and antidepressant consumption by at least one to two hours to minimize the risk of interactions.
2. Cold and Allergy Medications
The stimulant effect of caffeine doesn’t pair well with many cold and allergy medicines. “Many cold medications, especially those with decongestants like pseudoephedrine, already increase heart rate or blood pressure,” says Kennedy Erickson, PharmD, a pharmacist with Centralia Pharmacy in Centralia, Washington, and a member of the American Pharmacists Association.
Adding caffeine can compound those effects, leading to heart palpitations or anxiety, Dr. Osei-Boamah adds.
Whether you’re taking OTC cold and allergy medications or prescription ones, it’s important to talk to your doctor about the potential side effects of combining them with coffee.