For many of us, the day doesn’t truly begin until we’ve had our first cup of coffee. It’s comforting, energizing, and one of the most widely consumed beverages in the world. However, despite its seemingly harmless nature, coffee can interact with certain medications, from common cold remedies to antidepressants. This interaction may reduce their effectiveness or increase the risk of side effects.
What about tea? It also contains caffeine, but not in the same concentrations as coffee, and doesn’t appear to affect us similarly.
Cold and Flu Medications
Caffeine is a stimulant, meaning it speeds up the central nervous system. Pseudoephedrine, a decongestant found in cold and flu remedies like Sudafed, is also a stimulant. When combined, their effects can be amplified, potentially causing anxiety, headaches, rapid heartbeat, and insomnia.
Many cold medications already contain caffeine, further increasing these risks. Some studies suggest that the combination of caffeine and pseudoephedrine can elevate blood sugar levels and body temperature, which is particularly important for people with diabetes.
The stimulant effects are also a concern when caffeine is combined with medications for ADHD, such as amphetamines, or with asthma medications like theophylline, which has a chemical structure similar to caffeine. Their combined consumption can increase the risk of side effects such as rapid heartbeat and sleep disturbances.
Thyroid Medications
Levothyroxine, the standard treatment for hypothyroidism, is highly sensitive to when it’s taken. Morning coffee can interfere with this medication.
Caffeine accelerates intestinal motility, or the movement of food and waste through the digestive tract, reducing drug absorption time. On the other hand, caffeine can bind to it in the stomach, making absorption difficult. As a result, the drug’s bioavailability decreases, and less of it reaches the bloodstream where it’s needed.
This interaction is more common with levothyroxine tablet forms and less likely with liquid formulations. If drug absorption is affected, hypothyroidism symptoms may reappear, including fatigue, weight gain, and constipation.
It’s also advisable to separate coffee consumption from taking a type of medication for osteoporosis called bisphosphonates, which include alendronate and risedronate. In both cases, it’s recommended to take them on an empty stomach and wait 30 to 60 minutes before consuming food or beverages.
Antidepressants and Antipsychotics
The interaction between caffeine and mental health medications can be more complex.
One of the most commonly prescribed antidepressants are selective serotonin reuptake inhibitors (SSRIs) like sertraline and citalopram, usually prescribed for depression, anxiety, and other psychiatric disorders. Laboratory studies suggest that caffeine can bind to these drugs in the stomach, reducing their absorption and potentially decreasing their effectiveness.
Tricyclic antidepressants (ATCs), like amitriptyline and imipramine, are an older class of antidepressants that act on brain neurotransmitter levels. They’re used less frequently today due to their higher potential for side effects and greater risk of overdose compared to newer antidepressants like SSRIs.
ATCs are broken down by the liver enzyme CYP1A2, which also metabolizes caffeine. The competition between the two can slow down drug breakdown, increasing side effects, or delay caffeine elimination, potentially causing prolonged anxiety or agitation.
Clozapine, an antipsychotic, is also processed by CYP1A2. A study showed that drinking two or three cups of coffee could increase blood clozapine levels by up to 97%, potentially increasing risks of drowsiness, confusion, or more serious complications.
Pain Relievers
Some over-the-counter pain relievers, like those containing aspirin or paracetamol, include caffeine. Coffee can speed up the rate at which these drugs are absorbed, as it hastens stomach emptying and increases stomach acidity.
While this may help pain relievers work faster, it could also increase the risk of side effects like stomach irritation or bleeding, especially when combined with other caffeine sources. Although serious cases are rare, caution is advised.
Heart Medications
Caffeine can temporarily raise blood pressure and heart rate, usually three to four hours after consumption. For individuals taking blood pressure or arrhythmia (irregular heartbeat) medications, this can counteract the desired effects of the medication.
This doesn’t mean that individuals with heart conditions should completely avoid coffee, but they should monitor how it affects their symptoms. If necessary, consider limiting consumption or switching to decaffeinated.
In any case, if you’re ever unsure whether your medication and coffee make a good combination, consult a doctor or pharmacist. After all, everyone metabolizes caffeine differently: some feel great after three cups, while others experience side effects after just one.
