Mixing up caffeine and prescription drugs – yay or nay?
Disclaimer: This article is for informational purposes only and is not medical advice. Please consult with your health care professional with any medical or health related questions.
If you’re under medication and yearning to reach for that cup of joe, then this is a very important question.
According to a report by the New York Times, coffee can prevent some medications from working at their peak. 
Some interactions are even considered lethal. Others have mild to moderate effects, so you'll need to consult a medical professional to find out whether it's safe to go ahead with your java fix, or better do away with it.
Depending on the drug you're taking, interactions can lead to adverse effects such as:
With the help of rx.com, we’ve listed down a few drugs that may have direct impact on your system when mixed with caffeine.  They may be classified into:
Major – interaction may be lethal. DO NOT take this combination.
Moderate - Be cautious with this combination. Talk with your health provider.
Minor – Effects are felt albeit mildly. Consult a health provider.
What happens when you combine them?
Here are some of the effects from combining certain drugs with caffeine:
Ephedrine, medications for asthma (beta-adrenergic agonists), medications for depression (MAOIs), phenylpropanolamine
Because both caffeine and these drugs are stimulants, taking them at the same time will lead to serious side effects such as heart problems.
Taking caffeine with depression medications may lead to serious side effects such as faster heartbeat, high blood pressure, nervousness, among others.
Some medications for asthma include albuterol (Proventil, Ventolin, Volmax) metaproterenol (Alupent), terbutaline (Bricanyl, Brethine), and isoproterenol (Isuprel).
Warning: DO NOT COMBINE EPHEDRINE WITH CAFFEINE, as its effects might be too severe than others.
Adenosine and dipyridamole (Persantine)
These drugs are used for cardiac stress tests that doctors perform to check for heart conditions. Because caffeine might block their effects, make sure you drink your last cup of joe 24 hours before the stress test.
The interaction between these drugs and caffeine may cause the former to stay longer in the body, as caffeine slows down the breakdown of the drugs. Taking caffeine with them might cause high levels in the body and lead to more intense side effects.
Medications that slow blood-clotting (Anticoagulant / Antiplatelet drugs)
Caffeine can slow down blood-clotting, so taking anticoagulants with it might lead to bruising and bleeding.
Smokes and coffee? Tempting and habit-forming for some but it'll lead to rapid heart rate and blood pressure.
Water pills (Diuretic drugs)
Both caffeine and water pills can reduce potassium levels in the body, hence combining them will drop it tremendously.
Medications for diabetes
Caffeine can increase or decrease blood sugar. This interaction might either heighten or diminish the effects of diabetes treatment. For diabetics on the mend, it's advisable to watch the blood sugar when taking caffeine.
A good rule of thumb is to always check your diet with the doctor or pharmacist while being on the mend, and specifically ask about any caffeine interactions with the medicine you're about to take.
To be on the safe side, it’s best not to mix high levels of caffeine with any drug that is considered to be a stimulant, i.e. pseudoephedrine found in cold and allergy decongestants.
Of course the best way to steer clear of any trouble is to try to cut back on your caffeine while under medication, or settle for decaf in the meantime.
Erectile dysfunction. In combination, those are two of the ugliest words known to man. But can caffeine help you get it up?
Science hasn't found the definitive answer to this question, but one study concluded that fewer men who consume caffeine have problems performing. The study said:
Caffeine intake reduced the odds of prevalent ED, especially an intake equivalent to approximately 2-3 daily cups of coffee (170-375 mg/day). This reduction was also observed among overweight/obese and hypertensive, but not among diabetic men. Yet, these associations are warranted to be investigated in prospective studies