Cephalexin and Fatigue: What Users Say

• rin...
• February 17, 2009

Cephalexin for Bladder Infection "I usually never have side effects from antibiotics, but I had moderate dizziness and nausea. The nausea is not bad enough to send me to bed all day, but it does interfere with my daily schedule and leaves me extremely worn out and fatigued. It is frustrating. I have to take it four times a day for ten days."

• Pie...
• June 5, 2021

For Skin or Soft Tissue Infection "Prescribed in the ER after a superficial burn infected (4 cm). My dose is 500 mg x 4 times a day for 5 days, and I am on the second day. I called the hospital to ask about severe side effects. Been on antibiotics many times, but with this drug, the side effects are a lot heavier: - Extreme tiredness and weakness that I can’t even open my eyes - sleeping 10-12 hours (getting a pill every 6 hours), waking up with severe fatigue and body aches - my anxiety is off the roof - I have an ongoing heaviness feeling and breathing spasms in my chest - my stomach is so weird (not burn, not pain) like someone punching me, and I have pressure on my belly, feeling like I had a big meal, but I haven’t had anything other than 1-2 small meals in 3 days. - mild sore throat and minor cough - and my infection is not healing fast. At this stage, I am fighting with antibiotics more than the infection! + I am on probiotics and having yogurt. I hope this helps, other comments helped me to understand what’s going on with my body."

• Nev...
• Taken for less than 1 month
• October 21, 2020

For Bacterial Infection "I’ve been on this drug multiple times before for UTIs and had manageable side effects, usually headache and fatigue. This time I was put on it for a suspected bacterial infection. I took it for 3.5 days and increasingly had a severe headache, unbearable anxiety, and tachycardia requiring beta blocker usage. I don’t even know if anxiety is the right word, I literally feel like I’m on a hallucinogen or something, and sleeping has been impossible because of this feeling and the racing heart. It feels like a constant adrenaline surge I have no control over. Very weak as well, last night I felt like I couldn’t move my legs and almost went to the ER. I’ve been off of it for a couple of days now and finally slept last night, but still don’t feel right in my head. Will never take this again, I feel like I’m in hell."

• Mor...
• Taken for less than 1 month
• November 24, 2018

For Skin or Soft Tissue Infection "I had a staph infection in my nose, so my doctor put me on a week of cephalexin, 500 mg 3x daily. I was worried about GI side effects but was absolutely fine. The only side effects I noticed were very, very minimal fatigue and the slightest headache that was barely noticeable. I also took a once-daily probiotic with my dose in the evening just for peace of mind."

• Sam...
• June 23, 2021

Cephalexin for Bladder Infection "I've always taken ciprofloxacin for my chronic bladder infections, but this time around my doctor said he can't give it to me because of a new study that has nothing to do with me. So... I get Keflex. It's extremely slow at getting to the infection. I'm on day three, and I'm just now starting to feel a little better... I think. It also gives me horrific heartburn, headaches, fatigue, and I can't poop."

• ano...
• Taken for less than 1 month
• February 24, 2020

For Kidney Infections "I’m a healthy 20-year-old female who took this drug for about 4 days before having to call it quits. I’m 9 weeks pregnant at the moment. Not sure if that was making this worse or not, but I had the WORST fatigue I’ve ever experienced. I was physically unable to get out of bed other than to use the bathroom and shower. My body felt extremely heavy, and I was very confused and out of it. It made me nauseous, I was already experiencing 10 times worse. I ended up having a severe episode of heart racing for about 10 minutes on the 4th day. Blood pressure shot up to 150, and pulse got high. I threw this away. Listen to your body. I know it’s important to finish medications, but when the side effects are this bad, this is dangerous. Since my urine has completely stopped burning and it’s clear again, I have made another appointment with my doctor to confirm my infection is gone. Home tests came back negative. If not, I will request something else because this was AWFUL."

• 60i...
• March 26, 2016

Cephalexin for Skin or Soft Tissue Infection "With only 4 doses of 500 mg in 3 days instead of 3 a day, my symptoms got progressively worse. Blurred vision, dizziness, rash, leg pain and swelling, heat sensations in legs, muscle pain, back pain, swelling and pain in the stomach, and extreme fatigue. Stopped taking and reported adverse reaction to the pharmacy and will tell the doctor. Very glad I did not take the full dose. Use with caution if you are sensitive to meds."

• Rob...
• Taken for 6 months to 1 year
• June 13, 2019

For Bone infection "I've been on cephalexin for 5 months for a bone infection, and I have another month to go. I had a hip replacement, which became severely infected about a month later. The side effects of this are horrible. I get dry heaves at least 3 times per day, usually within an hour of taking it. Sour stomach is also another huge side effect. Extreme fatigue is another one. Being on this medicine has destroyed my sleep cycle. I wake up at 2-3 AM as I feel like I have to throw up, or my stomach just hurts. I started with intravenous injections through a PICC line for antibiotics, then it was changed to this green, nasty pill. Because of the sickness that it creates, I have missed almost 6 months of work. I try to get up in the morning, get ready for work, and end up dry heaving into the toilet. Four months into the use of this antibiotic, my hair is starting to fall out as well. This is a nasty medicine, but I do understand why it is needed. I really do not want my hip hardware removed."

• iha...
• Taken for less than 1 month
• December 18, 2016

For Skin or Soft Tissue Infection "I was prescribed 500 mg 4 times a day for 10 days to treat my folliculitis after shaving with a bad razor. The first day, I felt okay, but I'm on day 4, and I already feel like crap. I feel dizzy, extremely fatigued to the point where I feel like a lifeless potato, nausea, lightheadedness, and some mild abdominal pain here and there. I pretty much don't feel like doing anything. The folliculitis seems to be slowly improving, though it flares up again when I wake up, so I'm not entirely sure if this antibiotic is working. Might discontinue it if side effects get worse and try to get a different antibiotic."

• Jad...
• February 18, 2017

For Skin or Soft Tissue Infection "This drug has worked very well! I had a skin infection, with a urinary tract infection. I was put on the medicine for 10 days, 2 times a day. The first couple of doses, I didn't think that it was really working, but after 4 days of taking the medicine, then bumps started to go away, and I could urinate comfortably without any burning. On the 8th day, the bumps have completely dried up, and new skin is forming on top. I didn't really experience any bad side effects. The only side effects I had were minor diarrhea and fatigue. I would definitely recommend this medicine. My only wish would be that it would do a better job at clearing the bumps more effectively!"

• Anonymous
• January 25, 2020

For Bacterial Infection "Okay, so I recently had the ovarian removal of my left ovary at the beginning of the month. Fast forward about three weeks, and I see that my belly button, which was one of the areas they went in through, had a pool of pus in it (even though I had no fever, nor did I really have any redness or swelling). But I thought it would be better to be safe than sorry, so I went to the ER. The doctor barely looked it over, acted like he didn't even want to be there, and then sent his nurse in to prescribe me this garbage antibiotic, cephalexin. I am going on day four, and I'm done. There's no way I can continue this medication for 7 days. It in a short amount of time has already made me incredibly dizzy and fatigued, but has given me horrible stomach aches that come and go, diarrhea, and a feeling like I'm about to faint. It looks like the infection is gone, and if it's not, then I will go to my primary care doctor and have them prescribe me something else."

• jes...
• November 23, 2020

Cephalexin for Upper Respiratory Tract Infection "I went to the ER, they said I had a UTI, so they gave me Keflex 500 mg 4 times a day for a week. I despise ANY medication because of the side effects, but I didn’t want a kidney infection as that’s way worse, so I took it. I had nausea and some mild diarrhea about an hour in, normal, right? So, a few days in, I felt like I was hit by a truck. I woke up fatigued, my anxiety was so bad, and I developed an achy back that lasted a week even after I was done taking it! I still have some mild diarrhea every day, and it’s been a week since I’ve finished the medicine. I have no clue how I pulled through and took all of it. It did indeed clear up my infection, but I still feel sick. I know it’s a turn-off reading this, and it makes you not want to take the medicine, but you HAVE TO unless you want a kidney infection, which is way worse, and you’ll be put on even more antibiotics if that happens. Just pull on through, but if you genuinely don’t feel good when taking it, talk to your doctor."

• Kea...
• April 14, 2019

For Kidney Infections "Was put on cephalexin for a UTI, 500 mg twice a day for 7 days. Have just finished it after a horrendous experience. Very bad indigestion, anxiety, diarrhea first day, then constipated. Fatigue and headache. Shakes with hot and cold periods. After a day of finishing, the diarrhea has returned. Will never take this medication again."

• Pea...
• April 2, 2013

For Skin or Soft Tissue Infection "Penicillin VK did -0-; Keflex cleared up a bad infection from getting a 2-inch splinter out of the upper half of the bottom of my foot. Side effects were miserable: pain, fatigue, constipation; now 6 days since the last doses. Still, Keflex cleared up the infection that had a brown/yellow discharge. A strange antibiotic, but I'd rather have pain than cellulitis."

• Lov...
• Taken for less than 1 month
• July 4, 2021

For Skin or Soft Tissue Infection "I was prescribed this drug, 500 mg, for 7 days after rhinoplasty to prevent infection. If taken without food, I get nauseous and vomit, it also leaves a metallic taste in your mouth all day. I was also prescribed opioids, and that didn’t even cure the headaches from this drug. I am an emotional mess, crying all the time for no reason, insomnia and super fatigued, vivid nightmares, also, day 4, I got a horrible yeast infection. This is my last day, and I truly hope that I go back to normal. The depression and anxiety is the worst. Since it was not taken for a condition but for preventative purposes after surgery, I'm not sure if it worked, but the side effects are horrendous! Hope I never have to take this ever again!"

• May...
• Taken for less than 1 month
• June 21, 2022

For Bacterial Infection "I was prescribed a week's worth of cephalexin, four 500 mg capsules a day for a possible UTI. For the first 2-3 days of taking this medication, I felt like a bloated, dizzy, tired zombie and didn't feel an improvement. For one of those days, I got horrible constipation and indigestion. I couldn't pass gas. It scared me and made me anxious. I began to question whether this medication would actually work for me. I also recommend taking a probiotic with this medication since it does go hard on your digestive system in my experience. Thankfully, by the middle of the 3rd day, I finally felt some relief and started to feel a bit better. I had less pain. Unfortunately, though, the next couple of days were a rollercoaster with the persistent stomach pain and constipation. After treatment, urine tests came back free of infection. I still have some stomach pain, dizziness, fatigue, and some constipation, though hopefully it goes away soon. I will keep treating and healing my stomach with probiotics. Maybe I would try another medication next time."

• Ms ...
• Taken for less than 1 month
• November 7, 2020

For Kidney Infections "I started on cephalexin for a UTI three days ago, and it is a five-day course, twice per day (500 mg). Since I have horror side effects from Bactrim and Microbid. I am not feeling too good from this medicine either. Horrible fatigue, constant headaches, weak. I’m beside myself since I’m constantly getting UTIs. I will probably take Cipro next time. It’s not my first choice, however, it doesn’t make me feel this bad."

• Bec...
• Taken for less than 1 month
• August 3, 2019

"This cephalexin is an awful drug. I am taking the generic. I have taken it for three days as a precaution after surgery to remove plaques from my eyelids. My side effects: headache, diarrhea, muscle weakness, fatigue, fast heart rate, dizziness, depressed mood, and anxiety. Never again. I cannot wait to be off it. Doctors throw drugs at patients without consideration for side effects. I called the doctor, they said to complete the prescription. No wonder patients stop taking antibiotics. Awful drug."

• Aug...
• Taken for less than 1 month
• August 21, 2018

For Bacterial Infection "Doctor prescribed 500 mg 4 times a day for Septoplasty surgery. I’m on day 6. All it has done for me is stop the bacterial infection from my sinus and make me feel extremely tired. Can’t wait to finish this medication and hope fatigue goes away."

• SoM...
• Taken for less than 1 month
• April 9, 2018

For Kidney Infections "22-year-old female, got diagnosed with UTI (first time), started Keflex within 3 hours of the UTI symptoms starting. Right after taking the meds, I started getting chills (probably my body fighting off the infection), then a low-grade fever. Terrible headaches. Nausea. Dry mouth. Some dizziness when getting up. Super fatigued. Anxiety. Today is day 3 of taking 500 mg 2x a day. Still hurts to urinate, but not nearly as bad as day 1. Sometimes my headaches go away a couple of hours after drinking the med. Might need to call the doc tomorrow to see if I can switch meds, because I’m not sure if I can put up with the 10-day prescribed treatment."

• Bri...
• Taken for less than 1 month
• September 26, 2018

For Bacterial Infection "I got put on 500 mg twice a day for my recurring strep throat. Other antibiotics have cleared it up within a day. I am on day 5 and still see white spots. My tonsils are the size of golf balls, I can't even eat or swallow without shooting pains. I am a college student, and it sucks getting up from class and having to run to the bathroom every 20 minutes. Also, fatigue is an understatement."

• Ann...
• July 14, 2021

For Kidney Infections "I took this for 24 hours only. Had to stop after the first day because of the side effects. Headaches, extreme fatigue, sharp pains in my vagina, extremely bad diarrhea. It’s been a day and a half since I took the last one and the diarrhea is every 60 minutes and just water. I hope I feel better soon. Will never take this again."

• Vio...
• November 4, 2021

For Skin or Soft Tissue Infection "I was prescribed Keflex (500 mg) every 6 hours (4x) a day, for (7) days. I have only taken antibiotics once in my life when I was in high school. I am 28 now, just to give you some perspective. I had a cosmetic procedure, and my surgeon prescribed Keflex. The first day I was still coming off anesthesia, so I didn’t feel much. But the next day I felt horrible. I was so delirious, dizzy, and confused. That was just the start! As the days went on, I experienced blurred vision, sadness, extreme fatigue, and then insomnia. One night I slept for only one hour. I have suffered some acute memory issues and brain fog. I have to say that this experience has left me very afraid of antibiotics, and I only kept taking it because I had to in order to avoid possible infection. I will never willingly take Keflex or any other antibiotic. But I did not get an infection, so I guess it did its job."

• Dav...
• Taken for less than 1 month
• March 1, 2022

For Skin or Soft Tissue Infection "Little basal cell cancer removed. I always have some back, foot, hip pain, but now everything is so painful at the same time, horrible diarrhea, feel fatigued, almost like flu. I'm 68 with joint issues. It's bad to stop, but I can't do it. Worried about C.Diff. I took it before, no problem, but I can't function this time. Probably age and other conditions."

• Tuc...
• Taken for less than 1 month
• December 10, 2024

For Bacterial Infection "I took it for a UTI. Keep in mind all medications can have side effects depending on the person, and antibiotics are not an exception. That being said, cephalexin is one of the safest antibiotics for most people (unlike cipro and others in that class). It works well, and I did not notice any side effects, except maybe a bit of fatigue. Be aware but not neurotic about possible side effects is what I try to do. I have OCD and other neuropsych disorders, and they were not exacerbated. I recommend it, if not allergic or sensitive to it."