Warning: How Coffee Affects Common Medications and Your Health

 Coffee Warning: Could Your Morning Brew Be Interfering With Your Medications?

Many of us rely on coffee for that morning boost, but if you take certain medications, that daily cup could do more harm than good.

According to pharmacy expert Dipa Kamda of Kingston University, coffee — or more specifically, its active ingredient, caffeine — can interfere with a wide range of common medications. This can either reduce the effectiveness of your medicine or increase the risk of serious side effects.

So, which medications should coffee drinkers be cautious with? Let’s take a closer look.

☕ How Coffee Interacts with Common Medications

1. Thyroid Medication (Levothyroxine)
Drinking coffee too soon before or after taking thyroid medicine can reduce absorption by up to 50%. This means your symptoms (such as fatigue or weight gain) could return even if you’re taking your tablets correctly.
👉 Tip: Wait 30–60 minutes after taking your medication before drinking coffee.

2. Antidepressants
Caffeine may interfere with certain antidepressants:

• SSRIs (like sertraline, citalopram) may become less effective.

• Tricyclic antidepressants (TCAs) such as amitriptyline can cause jitteriness or worsened side effects, as caffeine competes with these drugs for breakdown in the liver.

3. ADHD Medications & Asthma Drugs
Stimulants like amphetamines (used for ADHD) or theophylline (used for asthma) already speed up the nervous system. Adding caffeine can worsen side effects like a racing heart, insomnia, and restlessness.

4. Cold & Flu Medications
Many decongestants (like pseudoephedrine in Sudafed) already act as stimulants. Combining them with coffee can amplify side effects: headaches, rapid heart rate, jitters, and even raised blood sugar — a concern for diabetics.

5. Heart Medications
Coffee can interfere with medications for irregular heart rhythms or high blood pressure, reducing their effectiveness. Patients with heart conditions should consider limiting their caffeine intake or switching to decaf.

6. Painkillers
Some painkillers (paracetamol or aspirin combinations) contain added caffeine. Adding coffee on top can increase the risk of stomach irritation or bleeding.

7. Bone Medications (Bisphosphonates)
Caffeine can hinder the absorption of osteoporosis drugs like alendronate and risedronate. Waiting before drinking coffee after taking these is recommended.

☕ It’s Not Just Coffee!

Caffeine is also found in tea, green tea, cola, energy drinks, and some over-the-counter medications. Be mindful of your total caffeine intake from all sources.

Everyone’s Body Reacts Differently

“Some people tolerate three cups of coffee with no issue, while others feel side effects after just one,” says Kamda. “Pay attention to your body and consult your pharmacist or GP if anything feels off.”

Key Takeaway

If you’re taking any regular medications — especially for the heart, thyroid, depression, ADHD, asthma, or cold/flu — it’s wise to double-check how caffeine might affect your treatment. A quick conversation with your pharmacist could prevent side effects and help your medications work as intended.

You don’t have to give up your coffee entirely — but knowing when and how to drink it can make a big difference to your health.

☕ Enjoy your brew safely!