Coffee is a daily ritual. It’s pleasure. It’s what keeps you alert and energised. But while you’re enjoying it, an annoying headache suddenly appears. There are always painkillers on your desk or somewhere visible at home - just in case - and you instinctively reach for them.

Perhaps you should reconsider. There are certain medications that are best not taken in combination with coffee, as The Independent noted in a recent article. And they’re far more common than you might think. According to the report, combining coffee with some medications can range from simply reducing their effectiveness to triggering potentially harmful side effects. From cold remedies to antidepressants, caffeine’s effect on the body goes well beyond providing a quick energy boost. The article also points out that tea contains caffeine as well, though generally in lower concentrations than coffee and it does not appear to affect people in quite the same way. So let’s take a look at which medications require caution.

Cold and flu medications

Caffeine is a stimulant, meaning it activates the central nervous system. Pseudoephedrine - a common decongestant found in many cold and flu medications - is also a stimulant. When taken together, their effects may intensify, potentially causing nervousness, restlessness, headaches, a rapid heart rate, or insomnia.

In addition, many cold medications already contain added caffeine, which can further increase these risks. Some studies also suggest that combining caffeine with pseudoephedrine may raise blood sugar levels and body temperature. Similar concerns arise when caffeine is combined with medications containing amphetamines, as well as certain asthma treatments such as theophylline, which has a chemical structure similar to caffeine.

Thyroid medications

Thyroid medications also deserve attention. These are drugs taken daily by many people and their timing often coincides with morning coffee. Levothyroxine - the standard treatment for an underactive thyroid - is particularly sensitive to timing. Your morning coffee may interfere with its effectiveness. Studies show that drinking coffee shortly after taking levothyroxine can reduce its absorption by up to 50%.

Antidepressants

The interaction between caffeine and mental health medications may be more complex than it seems. Selective serotonin reuptake inhibitors (SSRIs), such as sertraline and citalopram, are widely prescribed to treat depression, anxiety, and other mental health conditions. Lab studies suggest that caffeine may bind to these medications in the stomach, reducing their absorption and potentially decreasing their effectiveness.

For example, one study found that drinking two to three cups of coffee could increase blood levels of clozapine - a medication used to treat certain psychiatric disorders - by up to 97%, potentially raising the risk of side effects such as drowsiness, confusion, or even more serious complications.

Painkillers

And now to the most common category: painkillers. Did you know that some over-the-counter pain relievers, including those containing aspirin or paracetamol, already include added caffeine? Coffee may speed up how quickly these medications are absorbed by accelerating stomach emptying and increasing stomach acidity - which can enhance the absorption of certain drugs, such as aspirin.

While this may help painkillers work faster, it may also raise the risk of side effects like stomach irritation or even bleeding - especially when combined with additional sources of caffeine.

There’s no need to panic - most people have taken a painkiller before or after coffee at some point without serious consequences. Still, it’s something to keep in mind next time.

Heart medications

This may already be on the radar for some people - particularly those who take heart medications regularly. Caffeine can temporarily raise blood pressure and heart rate, typically for three to four hours after consumption. For individuals taking blood pressure medications or drugs used to manage heart rhythm disorders, caffeine may counteract the intended effects of their treatment.

That said, this doesn’t mean people with heart conditions must eliminate coffee entirely. It does mean they should pay attention to how it affects their symptoms and consider limiting their intake or switching to decaffeinated options if necessary.