Some of the symptoms of mixing alcohol and Flagyl can include cramps, abdominal pain, headaches, nausea and vomiting. This doesn’t mean that you’re mixing alcohol and Flagyl even at the same time. These symptoms can occur even if you wait several days after taking the medication before drinking. TIME: 22.02.2012 nick: helpdelra how long after taking flagyl can i drink How long until you can drink after finishing antibiotics specifically clindamycin and. People taking Flagyl are often instructed to avoid consuming alcohol while using the medication and for one day after finishing the course of antibiotics --- three days if you're taking oral capsules. You need to wait 48 hours after your last dose of a full course of metronidazole before consuming alcohol so to prevent side effects like nausea. It can actually make evn people who don't drink alcohol hurl if they take it on an empty stomach. Mkr sure you eat before you take this medicine. Patti Mkr sure you eat before you take this medicine. Patti Since the liver and intestines process and break down Flagyl in the body, side effects primarily impact the gastrointestinal system and can include nausea, vomiting, diarrhea, stomach cramps and constipation. Healthline and our partners may receive a portion of revenues if you make a purchase using a link on this page. These can be unpleasant, but drinking alcohol within three days of taking. How to use Flagyl. Take this medication by mouth as directed by your doctor. To prevent stomach upset, take this medication with food or a full glass of water or milk. Manufacturers of metronidazole advise that you should avoid drinking alcohol while taking the antibiotic and for 48 hours after finishing the course. This is because it takes roughly 48 hours for metronidazole to be cleared from the body of an average adult.