NEW YORK, May 15: For many people, coffee is a cherished part of their morning routine, offering a needed caffeine boost and even some health benefits. However, it may not mix well with certain medications, especially if taken early in the day.

Why coffee affects medications

Coffee can influence how medications are absorbed, broken down, or eliminated by the body. “It may speed up digestion, reducing the time your body has to absorb a drug,” explains Dr. Jennifer Bourgeois, Pharm.D. “It also competes with medications that rely on liver enzymes like CYP1A2, which may increase or decrease drug levels in your bloodstream.” This doesn’t mean you have to give up coffee — but timing matters.

Here’s how coffee can interact with specific types of medications:

Coffee can reduce the absorption of some antidepressants, such as escitalopram (Lexapro), potentially lowering their effectiveness. Others, like clomipramine and imipramine, share a liver enzyme with caffeine, meaning they may stay in your system longer, increasing side effects like jitteriness.

Coffee can cut the absorption of levothyroxine — a common hypothyroidism medication — by up to 50%. This can lead to fatigue, brain fog, and other symptoms of low thyroid function. Doctors recommend waiting 30 to 60 minutes after taking your thyroid meds before drinking coffee.

Medications like alendronate and risedronate are best taken with plain water only. Coffee, milk, or juice can reduce absorption, making these treatments less effective.

Decongestants like pseudoephedrine (Sudafed) are stimulants, just like caffeine. Taking both can increase side effects such as restlessness and a rapid heartbeat. For people with diabetes, the combination may raise blood sugar and body temperature.

Coffee can interfere with how the body processes medications like clozapine, haloperidol, or olanzapine. For example, caffeine can nearly double the concentration of clozapine in the blood, potentially leading to unwanted effects.

Bronchodilators like theophylline and aminophylline relax airway muscles but can cause side effects like nausea or irritability. Caffeine may amplify these reactions, especially if consumed in large amounts.

Blood thinners (like aspirin) and coffee can both slow blood clotting. Combined, they can raise the risk of bleeding or bruising. Coffee also affects how quickly some blood thinners are absorbed, potentially increasing their effects.

Coffee doesn’t need to be off-limits, but if you’re on one of these medications, it's important to adjust the timing. In general, taking your medication and waiting 30–60 minutes before drinking coffee is a good guideline. Always speak with your healthcare provider about potential interactions to ensure you’re getting the full benefit of your medication without unwanted side effects.