context: Alcohol often has harmful interactions with prescription medications, over-the-counter drugs, and even some herbal remedies. Alcohol interactions with medications may cause problems such as: Nausea and vomiting Headaches Drowsiness Dizziness Fainting Changes in blood pressure Abnormal behavior Loss of coordination Accidents Mixing alcohol and medications also may increase the risk of complications such as: Liver damage Heart problems Internal bleeding Impaired breathing Depression In some cases, alcohol interactions may decrease the effectiveness of medications or render them useless. In other cases, alcohol interactions may make drugs harmful or even toxic to the body. Even in small amounts, alcohol also may intensify medication side effects such as sleepiness, drowsiness, and light-headedness, which may interfere with your concentration and ability to operate machinery or drive a vehicle, and lead to serious or even fatal accidents. Because alcohol can adversely interact with hundreds of commonly used medications, it's important to observe warning labels and ask your doctor or pharmacist if it's safe to use alcohol with any medications and herbal remedies that you take. According to the CDC, about two-thirds of American adults over age 18 at least occasionally use alcohol. Of these, about 51% are current regular drinkers (defined as at least 12 drinks in the past year), and about 13% are infrequent drinkers (defined as up to 11 drinks in the past year). Use of prescription and non-prescription drugs, as well as herbal remedies, also is extremely prevalent. Partly because of the obesity epidemic, Americans of all ages are taking more drugs to control chronic conditions such as diabetes, high blood pressure, and elevated cholesterol. Because the incidence of chronic conditions increases with age, older Americans are especially likely to take prescription medications -- often as many as 10 per day -- many of which likely react adversely with alcohol. As the population ages, the problems associated with mixing alcohol and medications are certain to increase. In older adults especially, alcohol use may increase the risk for falls, serious injury, and disability related to balance problems. Alcohol use also may trigger or worsen certain medical conditions. When alcohol use is combined with multiple medications, it may magnify these problems. Older adults don't metabolize alcohol as quickly as younger adults do, so alcohol stays in their systems longer and has a greater potential to interact with medications. Even though most people over 65 drink less than the maximum recommended amount, this drinking is still considered harmful for many of them, due to their general condition, medical problems and medications. Hundreds of commonly used prescription and over-the-counter drugs may adversely interact with alcohol. These include medications used for: Allergies, colds, and flu Angina and coronary heart disease Anxiety and epilepsy Arthritis Blood clots Cough Depression Diabetes Enlarged prostate Heartburn and indigestion High blood pressure High cholesterol Infections Muscle pain Nausea and motion sickness Pain, fever, and inflammation Seizures Severe pain from injury, post-surgical care, oral surgery, and migraine Sleep problems Examples of commonly used prescription drugs associated with serious alcohol interactions include heart medications, which can cause rapid heartbeat and sudden changes in blood pressure; nonsteroidal anti-inflammatory drugs ( NSAIDs), which can increase risk of heart attacks, strokes, ulcers and stomach bleeding; blood-thinning medications, which can lead to internal bleeding; and sleep medications, which can lead to impaired breathing, drowsiness, motor control, and unusual behavior. One of the most common causes of severe liver damage -- including some cases requiring a liver transplant -- is a combination of the pain reliever acetaminophen (available over the counter as Tylenol and in some prescription drugs) and alcohol. Other serious alcohol interactions are associated with over-the-counter antihistamines and herbal remedies such as kava kava, St. John's wort, chamomile, valerian, and lavender. Although most drugs are safe and effective when used as directed, it's important to read warning labels on all medications. Many popular pain medications -- and cough, cold, and allergy medications -- contain more than one ingredient that can adversely interact with alcohol. If you're not sure if a medication can be combined with alcohol, avoid any alcohol consumption until your doctor or pharmacist has told you that it's safe to mix the two.