The results of mixing alcohol with antibiotics are varied. Most of the time, drinking alcohol with antibiotics does not lead to adverse reactions. This is not the case in all instances, however. Depending on the type of antibiotic, combining alcohol with antibiotics can lead to decreased and sometimes increased potency of antibiotic medication. This fact lends to unpredictability in the dosage and desired outcome of a prescription.
Most side effect profiles of antibiotics include stomach upset, dizziness, and drowsiness; the side effects of alcohol consumption are similar. When combined, the risk of being affected from these common, but unpleasant, side effects is increased. There are some antibiotics, including metronidazole, tinidazole, and trimethoprim-sulfamethoxazole, that contraindicate the use of alcohol completely. Mixing these substances can lead to more severe reactions including rapid heart rate, nausea, and headache. In addition to becoming ill, which may require hospitalization, vomiting or diarrhea can cause a significant amount of the antibiotic to be lost, resulting in the discontinuation or prescription of a longer course of the antibiotic.
The liver is the primary organ used by the human body to metabolize antibiotics and alcohol. Combining alcohol with antibiotics can tax the liver and cause it to overwork and become inefficient. As the two substances "fight" for the use of the organ, either one of them can be stalled inside the body waiting to be metabolized. Side effects can be increased, while the effectiveness of the drug is decreased. Alcohol can decrease the effectiveness of many medications that may be used in conjunction with antibiotics to treat an infection as well.
Doctors are careful when prescribing antibiotic medications to patients with chronic liver disease such as cirrhosis or hepatitis. If chronic alcohol abuse is a factor, some antibiotics such as doxycycline need to be regulated because a higher dosage may be needed to counteract liver dysfunction. Kidney dysfunction is also considered when prescribing antibiotic medication, as alcohol is known to have harmful effects on this system. When a healthy individual is considering combining alcohol with antibiotics, it is still important to read the insert included with the prescription in order to be aware of any contraindications. The individual should ask the pharmacist or prescribing physician any additional questions about the drug and conditions that might interfere with taking it.