Mix one part Red Bull with two parts vodka and what do you get? If a headache comes with the buzz, it may not be wise to add a Tylenol chaser—especially if you're a heavy coffee drinker. A study published online today in the journal Chemical Research in Toxicology found that big doses of caffeine (found in Red Bull and regular coffee) combined with acetaminophen or Tylenol may well raise the risk of liver damage. When researchers from the University of Washington in Seattle mixed the caffeine-equivalent of 12 cups of coffee and the maximum daily allowable dose of acetaminophen with a liver protein, they found that the combination triples the output of a toxic byproduct made when the protein processes acetaminophen. Alcohol, already shown to be harmful in combination with Tylenol, could increase the toxic effects even more.
The study is a reminder that, when it comes to drugs and food, you have to consider the sum of the parts. The Food and Drug Administration keeps a list of common food and drug interactions. Here are some hazardous mixtures:
• Antihistamines: Don't take these drugs with alcohol, since mixing the two can increase the level of drowsiness caused by some of the medications.
• Asthma medications: Avoid caffeinated beverages and foods because both caffeine and bronchodilators (theophylline, albuterol, epinephrine) act as stimulants, increasing nervousness and jitteriness. Alcohol should also be avoided when taking theophylline, since it can increase the risk of side effects such as nausea, vomiting, headache and irritability.
• Diuretics: Used to treat high blood pressure and edema, diuretics can interact with specific nutrients. Triamterene, for instance, shouldn't be combined with potassium-rich foods like bananas, oranges, green leafy vegetables, or salt substitutes that contain potassium. An excess of potassium in the bloodstream can lead to heart palpitations.
• Heart medications: Beta blockers and nitrates shouldn't be taken with alcohol because this can result in dangerously low blood pressure. Some ACE inhibitors (captopril and moexipril) shouldn't be taken right before or right after eating. Cholesterol-lowering statins shouldn't be taken with alcohol since the combination can increase the risk of liver damage. The blood thinner warfarin shouldn't be combined with foods rich in vitamin K, like broccoli, spinach, kale, or cauliflower, since these may reduce the drug's effectiveness.
If you find yourself dealing with a Red Bull-vodka headache, use aspirin or ibuprofen, recommends study co-author Sidney Nelson, dean of the school of pharmacy at the University of Washington. Both appear to be less problematic. But avoid combination painkillers like Excedrin, which contain acetaminophen, aspirin, and caffeine. The small amount of caffeine and acetaminophen in these products won't normally pose liver risks, Nelson says, but they might be harmful when taken during a drinking binge.