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Metronidazole and Nausea: What Users Say

Brand names: Flagyl, Metro, Flagyl 375, Flagyl IV, Likmez Metro IV

Nausea: mentioned by 820 users (33.7%)

Based on user experiences from 2,431 Metronidazole reviews, the following table shows the most commonly mentioned side effects.

All user comments are moderated by Drugs.com. Each review is verified for relevance and screened for inappropriate content. Side effects are user-reported and not clinically verified.

nausea 33.7%
headaches 21.1%
dizziness 13.9%
diarrhea 12.4%
bad taste 10.2%
tiredness 9.7%
metallic taste 8.8%
upset stomach 8.1%
loss of appetite 7.9%
vomiting 7.8%

Reviews for Metronidazole

Commonly mentioned side effects
  • Mar...
  • August 27, 2019

Metronidazole for Diverticulitis "First diverticulitis (DVT) attack, was in such pain & had been in a very stressful situation. I had CT and diagnosed with DVT and prescribed Flagyl & cipro. Became very ill, nauseated, headache, confused, lost my way back to husband's hospital room. Very frightening & debilitating. Called former GI dr & he took me off 1 of the drugs & I slogged it out & finally got well again but at what cost? I'm one that get frequent flare-ups. Now take 250 mg amoxicillin 3X a day for 10 days which is very inexpensive & have no side effects. Nothing to compare to the horrible, torturous side effects of those other 2 drugs. I sought advice from 3 GI doctors and consulted 3 colorectal surgeons. It is hard to imagine that they still do not really know what causes these DVT flare-ups. It's all best guess & try this or try that. With so many people suffering from DVT I can't find a major study being conducted to identify any specific bacteria that seems to get out of hand causing these repeated infections."

3 / 10
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  • dog...
  • Taken for less than 1 month
  • April 11, 2021

Metronidazole for Bacterial Infection "If I could give this medication 0 stars, I would. My gyno prescribed me this for bacterial vaginosis. My side effects were horrible... increased anxiety/panic attacks, nausea, horrible taste in my mouth, and I had the most vivid nightmares. I would wake up trembling/shaking out of my sleep, and it took me a few days to realize that it was the Flagyl that was making me feel this way. I will never take this medication again unless I absolutely have no choice. I’m glad I’m not the only one that had a terrible experience on this drug."

1 / 10
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  • Jam...
  • Taken for less than 1 month
  • September 7, 2018

Metronidazole for Diverticulitis "I am a Flagyl survivor. Today I finish my 48 hours of it getting out of my system following 7 harrowing days of physical assault. Day 3 brought debilitating stomach pain, incapacitating nausea, dizziness/brain fog. The hospital had to confirm for me that the diverticulitis was not worse, it was the medication’s side effects. What??? Is this 2018? I am a healthcare provider, and this has given me insight into people’s distrust of the medical profession. The medicine was first patented in 1963... now in generic form... and never an attempt to refine the med to reduce side effects? Or produce alternatives? I have an intense full-time job, got lucky I was sick over the long weekend (????) and just made it through day 6 and 7 at work with the use of partially effective Zofran (anti-nausea). Find any alternative drug or treatment. I just lost 10 days of my life, first to illness, then to the treatment. I believe quality of life matters. Good luck diverticulitis sufferers! I’m with you in spirit."

2 / 10
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Frequently asked questions

  • try...
  • August 9, 2016

Metronidazole for Diverticulitis "This is my third diverticulitis event in 9 years, and each time I have been treated with Cipro and Flagyl, but I do not remember feeling so awful the first two times, nor do I remember the horrifically bad taste of the metronidazole (Flagyl). I can hardly get it down, and after I do, the horrible taste in my mouth is beyond description. I have resorted to immediately grabbing a lollipop to coat my mouth and pharynx with the sweet sugary taste, which actually does help. On top of that, I am nauseated, dizzy, have a foggy brain, and nothing tastes normal or good, not even water. I am thankful for the improvement in the abdominal pain, as that shows that the horrid stuff is working, but dang, can't they put it in a capsule?"

6 / 10
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  • Amy...
  • October 3, 2016

For Diverticulitis "I was on metronidazole (Flagyl) & ciprofloxacin for diverticulitis. Let me start off by saying these two medications together SUCK, however they DO work. I have never had any problems with medications...ever (in 40 years). This time though, at times, I thought I was dying! Best described as the worst flu ever. Massive nausea, occasional vomiting, diarrhea, exhaustion, horrible taste in my mouth, nothing tasted good, and my appetite was bad. Day 4 was the peak of feeling awful. I went to every review site trying to gather what worked to curb the symptoms. Everyone is different, so what worked for others didn't necessarily work for me. Here is what did work for me a bit, in case it can help anyone else. 1.) Try not to take them together. Split up the doses by like an hour or so. 2.) Take each dose with a little food (even if you aren't hungry), something bland. DO NOT USE DAIRY PRODUCTS. This made my nausea worse! 3.) Have mints or candy at all times. Your mouth will feel gross and things will taste funny. However, I found spearmints also helped soothe the tummy a bit. 4.) Pepto-Bismol. 5.) Try not to take them immediately before bed at night. Give it about an hour or two. I noticed nausea will wake me up throughout the night if I take them too close to going to sleep. GOOD LUCK, and remember: Your doctor prescribed these for a reason. A reason that could turn into life-threatening unless you get it controlled. The worst thing ever is to start taking an antibiotic and then stopping it mid-cycle, as your body then becomes immune to it and is essentially ineffective."

7 / 10
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  • Cal...
  • September 20, 2020

Metronidazole for Bacterial Infection "Flagyl was a miracle drug for my SIBO/IBS. The first time I used it 20 years ago I was unexplainably sick/nauseated and losing weight for months, and after a colonoscopy and gallbladder scan, the docs didn’t know what was wrong. One happened to put me on Flagyl, and the next day I was better! I had no problem with this drug at all. I have just recently had the same flare-up for the past 6 weeks, and my doc put me on Flagyl. Within 4 hours, I was feeling better. I am 7 days into a 10-day run, and I haven’t felt this good in years. I am 66, have motility issues, and this drug worked wonders for SIBO/IBS."

10 / 10
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  • Jul...
  • January 20, 2021

For Bacterial Vaginosis "I am on day 4 out of 7 taking this metronidazole antibiotic. I was prescribed 2 per day. I have awful fatigue and brain fogginess. I feel like I am in a dream, my stomach is so sick, and I have super painful stomach cramping that had me in tears today. Diarrhea as well. I’m very nauseous even if I take this with food. This medication is very hard to take. I want to give up on it. I’ve never experienced side effects like this."

1 / 10
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More FAQ

  • Jul...
  • January 20, 2021

For Bacterial Vaginosis "I am on day 4 out of 7 taking this metronidazole antibiotic. I was prescribed 2 per day. I have awful fatigue and brain fogginess. I feel like I am in a dream, my stomach is so sick, and I have super painful stomach cramping that had me in tears today. Diarrhea as well. I’m very nauseous even if I take this with food. This medication is very hard to take. I want to give up on it. I’ve never experienced side effects like this."

1 / 10
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  • Anonymous
  • Taken for less than 1 month
  • April 22, 2018

For Trichomoniasis "I had gotten diagnosed with trichomoniasis and they prescribed me this medication. The instructions were to take 4 pills at once (2000 mg). I thought that was absurd. Naturally paranoid with taking medication in the first place, I looked up the reviews and I did not see positive feedback. A lot of people said they had gotten sick or had heart palpitations, so my anxiety kicked in and it took me four days to finally suck it up and take it. Well, I took it before bed (it said dizziness may occur) and I went right to sleep. Woke up and felt nothing. Long story short, make sure you take it on a full stomach, take it before bed, and you should be fine. Don’t let reviews scare you because chances are those people didn’t follow the instructions. You'll be fine!"

10 / 10
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101 Report
  • Net...
  • Taken for less than 1 month
  • November 17, 2019

Metronidazole for Bacterial Infection "Nah-ah. Never again. Worst medication I have ever taken. On my second day of taking this tablet, I was feeling nauseous. My appetite was bad, and my stomach felt sick. Headaches, fatigue, easily irritated. I dreaded taking it when the time came. It made me absolutely miserable. My resting heart rate went up to 105 bpm. Even raising my voice ever so slightly made my heart pound harder. It was very stressful. Steer clear. I felt stupid taking this medicine for side effects that were much worse than the reason I needed them for."

1 / 10
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  • aaa...
  • Taken for less than 1 month
  • April 12, 2021

For Bacterial Vaginosis "I'm always prescribed this for when I have bacterial vaginosis - 500 mg 2x/day for 7 days. I always make sure to take it on a full stomach to avoid nausea. The only real side effect I experience is dark yellow/orange urine after taking it for a few days, and it goes away when I stop taking it, and slight nausea and loss of appetite. Like I said, having a full meal before taking it helps a lot. It works as intended. My only complaint is the horrible bitter taste when taking it, so to avoid that, I have to take it with extremely sweet drinks like some soda and try to swallow it fast so I don't taste it."

8 / 10
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63 Report
  • MsN...
  • Taken for less than 1 month
  • April 23, 2019

For Trichomoniasis "So I'm a female, I went in for an exam a month ago and my results came back positive for chlamydia. I was prescribed the 2 oral antibiotic tablets to take as one dosage. I didn't have symptoms, of course, beforehand and had some after taking the medicine, so I assume it was flushing out. So I went for my follow-up a few weeks later and had another exam. I had trich and BV, so I was prescribed the 4 pills of flagyl 500mg to take as one dosage, followed up by one dosage of diflucan 150 mg because I get yeast infections after taking antibiotics. I highly recommend taking the one dosage of four pills instead of the seven or two days. I ate before taking the medicine, however, later on in the day, I felt nauseous. I had a metallic taste in my mouth even when trying to drink water, so I just slept it off. However, the next day, I'm feeling great, no odor, no discharge, no nothing. And my results came back negative for any other STDs."

8 / 10
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  • Anonymous
  • Taken for less than 1 month
  • October 18, 2013

Metronidazole for Bacterial Infection "Been on this for a week! Even though it's taking care of my issue, I can't wait to take my last pill. I've been sick to my stomach, loss of appetite, headache, dizzy, blurry vision, disoriented, fatigued, can't sleep well. Just ready for this course to be over."

8 / 10
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  • Eri...
  • September 12, 2019

Metronidazole for Bacterial Infection "Just finished taking a week’s worth of Flagyl, twice a day. It’s brutal, but your body will adjust. It helped me to sip ginger tea when nauseous and to eat a small meal and drink a full glass of water when I take it. As a nurse, I just want to remind people that even if this drug is wrecking your body, always consult your doctor before stopping treatment. If you only take 4/5 days and are prescribed 7, the bacteria left in your body will have time to develop an immunity to meds, and your infection will rebuild and turn into a superinfection and the antibiotics won’t work next time. There is a reason antibiotics are given over prescribed amounts of time, and stopping them before completion is going to bring on something much worse than side effects. Trust me, I wanted to die taking this medication - many sleepless nights and bad side effects - but an antibiotic-resistant infection is much worse than one week of side effects. If you absolutely have to, call your doctor first. Good luck!"

5 / 10
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  • Num...
  • November 19, 2019

Metronidazole for Diverticulitis "Taking the antibiotic combo metronidazole and Cipro for a flare-up of diverticulitis and now on day 4. My side effects are that I feel so dreadful, very weak, no appetite at all, dizzy, nauseated, night sweats, vaginal discharge, diarrhea, and I have lost 7 lbs already. Forcing small bits of food down as I have to eat something, drinking lots of water, feel nauseated. I am in the UK. This medicine is utterly brutal and toxic, but my pain is nearly gone. Longing for day 7 to end the drama."

4 / 10
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  • Amb...
  • Taken for less than 1 month
  • December 27, 2019

For Bacterial Infection "I recently had my gallbladder removed a week ago. Woke up 3 days later with blood pouring out of me at the other end. Went to the ER where they did a CT scan and showed colitis. The doctor put me on Flagyl and Cipro for 10 days. Woke up today, 5 days later, with horrible nausea, vomiting, and diarrhea. I am extremely dehydrated and feel horrible. I literally feel the worst possible. Does anyone else feel bad and weak on these meds?"

4 / 10
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  • bea...
  • April 23, 2016

For Trichomoniasis "I have trich and I was put on the 4 pills at once of 500mg. I took it Thursday at noon. I was fine. I have to say the taste is not the best. Put it way back on your tongue, drink water, and swallow. Don't start smacking your tongue around, that's what makes you taste it. So I took it, went to work, and around 9 I got nauseous. It came and went. At 11:30 at night, I was very nauseous, I just went to sleep. The next day I noticed a lot less itch and burn. Absolutely no more nausea. Today, Saturday is day two, I feel good. Again, I'm not 100% clear because occasionally I feel a little itch, but I like this pill. Also, on day one on the pill, I had a one-time heavy discharge. It was like the infection came out. For those who ask, if you get the one-time four pills of 500mg, you must take all four at once. Trust me, you'll be okay."

10 / 10
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  • And...
  • February 18, 2020

For Diverticulitis "Diagnosed with diverticulitis and put on Cipro and Flagyl. Today is Day #10, hallelujah! I had diverticulitis flare-ups 4 and 5 years ago. I forgot how sick these drugs make me. I can’t keep food down, nauseous 24 hours a day except when I take Zofran, upper stomach pains, reflux, heartburn, dizziness, listless, and spend most of my day sleeping. This came at the most inopportune time, I just had major knee surgery two weeks before the attack, which has hindered my healing process as I can’t get up to proceed with physical therapy, it’s too nauseating to move around. If I ever get another attack, I will never take these drugs again. There has to be a better way! I want my life back."

9 / 10
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60 Report
  • smb...
  • Taken for less than 1 month
  • March 3, 2016

For Trichomoniasis "I was prescribed the 2000mg one-time dosage. Yes, the pills have a horrible taste, but I'd rather taste that than have the symptoms of trich! I've taken the same meds for BV before and usually end up pretty tired after about 2 hours or so. I took this about 12 hours after a night of heavy drinking. Have felt a little nauseous and had loose stools and a little headache. But it's been 3 hours since I've taken it, and the odor is weaker, and the discharge has dramatically decreased! Bye-bye trich and bye-bye cheating boyfriend that gave it to me!"

10 / 10
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94 Report
  • sic...
  • May 29, 2019

For Diverticulitis "I have had my first bout of diverticulitis. I was prescribed Flagyl and Cipro. The first day I took them together, I got a massive headache and felt awful. On the second day, I did this: Cipro at 6 a.m. on an empty stomach with 500 ml of water. I had coffee an hour later. At 8 a.m., I took Flagyl with a glass of milk (I can't take Cipro with milk because it has calcium, but you can take Flagyl with milk) or applesauce. I have no bad taste with milk. Then I repeated this at 6 p.m. with Cipro and 500 ml of water, and at 8 p.m. with Flagyl and milk, and that's it. I get no headache, no nausea, no vomiting, nothing, and I am slowly getting better. I think taking Cipro and Flagyl together causes a reaction and gut issues, so it is best to separate them out, let them work separately, and not mix the medications together. Also, Flagyl is an antiparasitic, so it might be causing a bit of Herxheimer reaction after a few days."

9 / 10
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  • MsA...
  • January 25, 2014

Metronidazole for Diverticulitis "Took Flagyl and Cipro together - felt worse than I did before - all the side effects everyone is mentioning. However, the alternative - raging infection - not really an option. Taking my diet seriously moving forward."

9 / 10
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105 Report
  • Ugh...
  • Taken for less than 1 month
  • September 8, 2019

Metronidazole for Bacterial Infection "I almost think it’s better for people to read this if they also had a bad reaction and don’t want to feel so alone because I have heard of this working really well for some people, as with any drug. It seems to me that if you do have a bad experience with this, it isn’t mild, but extreme, as was the case for me. I don’t do well on many antibiotics, but this one was in a class of its own for me. It took me over three months to feel somewhat normal again. It went from bad hives to feeling like my joints were trying to leave my body, to feeling incredibly dizzy and nauseous, to stomach pain. It sounds dramatic, but I have never felt worse on any antibiotic. What it was prescribed for was so much easier to handle than the side effects of this train wreck. Every inch of my body felt off on this medicine. Even mentally, it gave me anxiety. The only antibiotic that came close to this one as far as feeling horrible is Cipro."

1 / 10
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  • Ame...
  • September 23, 2015

Metronidazole for Diverticulitis "I'm a 36-year-old active female diagnosed with diverticulitis. I took the combo of meds and am on day 7 now. I work out 6 days a week and have had to modify my workouts and weight lifting because I feel absolutely drained, weak, and muscles ache. (This, of course, was advised against by both doctor and pharmacist but alas, I am a knucklehead.) I have the metallic taste as well in addition to nausea with the meds. However, I would prefer these side effects to the pain associated with diverticulitis."

8 / 10
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  • Ame...
  • September 23, 2015

Metronidazole for Diverticulitis "I'm a 36-year-old active female diagnosed with diverticulitis. I took the combo of meds and am on day 7 now. I work out 6 days a week and have had to modify my workouts and weight lifting because I feel absolutely drained, weak, and muscles ache. (This, of course, was advised against by both doctor and pharmacist but alas, I am a knucklehead.) I have the metallic taste as well in addition to nausea with the meds. However, I would prefer these side effects to the pain associated with diverticulitis."

8 / 10
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90 Report
  • Duf...
  • Taken for less than 1 month
  • June 9, 2020

For Bacterial Infection "Given metronidazole for a tooth infection, wish I’d never gone to the dentist. Nausea, vomiting, diarrhea, sleeping endlessly, shivering even when wrapped in layers, snuffles, and borderline psychosis. Luckily, I only have 2 tablets left. Never again!"

2 / 10
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Reviews may be edited to correct grammar/spelling or remove inappropriate content. Reviews appearing to come from parties with a vested interest are not published. This information is not intended to endorse any medication and should not replace the expertise and judgment of healthcare professionals.