Cephalexin for UTIs: Dosage, Side Effects, and Preventive Measures
By Diana Rangaves, PharmD, RPh
Urinary tract infections (UTIs) are common and can cause discomfort, frequent urination, and complications if untreated. Antibiotics like cephalexin for urinary tract infections are often the first line of defense due to their effectiveness in treating bacterial infections.
If you’ve been prescribed cephalexin for a UTI or want to learn more about it, this guide covers everything you need to know. Here, you’ll learn how it works, the proper dosage, and the potential side effects.
What Is Cephalexin and How Does It Work?
Cephalexin, commonly known by its brand name Keflex, is a first-generation cephalosporin antibiotic.[1] It is often prescribed to treat bacterial infections, including those affecting the urinary tract, respiratory tract, skin, and soft tissues.[2] Its broad-spectrum activity makes it effective against many gram-positive and some gram-negative bacteria.[3]
Cephalexin works by interfering with the bacteria’s ability to build and maintain its cell wall. It binds to specific proteins (penicillin-binding proteins) involved in synthesizing peptidoglycan, a key component of bacterial cell walls. This weakens the cell wall, causing it to rupture and kill the bacteria.[3]
Due to its mechanism of action, cephalexin is particularly effective against common UTI-causing bacteria, such as Escherichia coli (E. coli) and Proteus mirabilis. It’s typically used when a targeted approach to bacterial eradication is needed.
Cephalexin Dosage for UTIs
The typical dosing schedule for cephalexin in treating UTIs has always been 250-500 mg taken four times daily.[1] This frequent dosing ensures consistent levels of the antibiotic in the bloodstream to effectively combat bacterial infections.
However, recent studies, including one highlighted by the Infectious Diseases Society of America (IDSA), have raised questions about whether such frequent dosing is necessary for uncomplicated UTIs. The study found that a twice-daily dosing regimen of cephalexin is just as effective and safe as the traditional four-times-daily approach for treating uncomplicated UTIs in women.[1]
Recommended Cephalexin Dosing for UTIs
- Adults: Dosage is usually 250 mg every 6 hours or 500 mg every 12 hours.[4]
- Children: Dosage is typically based on body weight (e.g., 25-50 mg/kg/day) and divided into 2-4 doses.[5]
Always consult your healthcare provider for personalized dosing instructions.
Cephalexin Side Effects and Risks
While cephalexin for UTIs is generally well tolerated, several side effects have been reported, ranging from mild to severe. Understanding these risks can help you know when to consult a healthcare provider.
Common side effects[5]:
- Gastrointestinal issues: Nausea, vomiting, diarrhea, and abdominal discomfort are frequently reported.
- Hypersensitivity reactions: Allergic responses such as a rash, urticaria (hives), and pruritus (itching) may occur.
Serious side effects:
When to consult a healthcare provider:
- If you experience persistent or severe diarrhea, abdominal cramps, or signs of dehydration
- If you develop signs of an allergic reaction, such as rash, itching, swelling, dizziness, or trouble breathing
- If you notice unusual bleeding, bruising, or signs of infection (e.g., fever, sore throat) that could indicate blood cell abnormalities
Who Should Be Cautious of Using Caphalexin?
Even if cephalexin is a widely prescribed antibiotic, it may not be suitable for everyone. Individuals under these conditions should be cautious of this medication:
- Allergies to Cephalosporins or Penicillin: Cephalexin is a cephalosporin antibiotic, and individuals with a known allergy to cephalosporins or severe reactions to penicillin may experience cross-reactivity.[7] Symptoms of an allergic reaction can include rash, swelling, or difficulty breathing.[7]
- Severe Kidney Disease: Cephalexin is primarily excreted by the kidneys. Individuals with severe kidney impairment may require dose adjustments or alternative antibiotics to prevent drug accumulation and potential toxicity.[8]
- Pregnancy and Breastfeeding: Although cephalexin is considered relatively safe during pregnancy and breastfeeding, it’s essential to consult a healthcare provider to weigh the benefits and risks. The drug does pass into breast milk in small amounts, which might affect nursing infants.
- Concurrent Medications: Cephalexin may interact with other medications, such as blood thinners (e.g., warfarin), potentially increasing the risk of side effects like bleeding.[9] A healthcare provider should review all medications being taken before prescribing cephalexin.
Preventing Future UTIs
Recurrent urinary tract infections (UTIs) can be a frustrating experience, but understanding certain habits and lifestyle factors may help reduce the risk of recurrence.
- Hydration matters: Drinking plenty of water helps flush bacteria out of the urinary tract. Staying hydrated may be one of the easiest ways to support urinary health.[10]
- Personal hygiene practices: Maintaining good hygiene, such as wiping front to back after using the restroom, can reduce the spread of bacteria.[11]
- Urination habits: Emptying the bladder regularly and completely may help minimize the opportunity for bacteria to multiply. Urinating soon after sexual activity is also a common recommendation for reducing UTI risks.[12]
- Clothing choices: Wearing breathable, loose-fitting clothing and undergarments made from natural fibers like cotton can help reduce moisture buildup, which can create a less favorable environment for bacteria.
- Dietary considerations: Some research suggests that cranberry products and other natural options might support urinary health.[13] While not a guaranteed solution, these can be a simple addition to a balanced diet.
- Understanding risk factors: Conditions such as diabetes, hormonal changes, or a history of UTIs may make some individuals more prone to infections.[14] Being mindful of these factors and discussing them with a healthcare provider could lead to tailored prevention strategies.
- Probiotics: Some studies suggest that certain strains of probiotics may help maintain a healthy balance of bacteria in the gut and urinary tract, potentially reducing the risk of UTIs.[15]
- Personal hygiene practices: Maintaining good hygiene, such as wiping front to back after using the restroom, can reduce the spread of bacteria.[11]
While these tips can contribute to overall urinary health, always consult a healthcare professional for specific recommendations or concerns regarding recurring UTIs.
<h2>Alternative Treatments for UTIs</h2>
While antibiotics like cephalexin are the primary treatment for urinary tract infections (UTIs), alternative options may be considered in specific cases or as supplemental approaches.
<h3>Other Antibiotics</h3>
If cephalexin isn’t suitable due to allergies, resistance, or other factors, healthcare providers may prescribe:
<ul>
Non-Antibiotic Options
In some cases, non-antibiotic therapies may be explored, including:
<ul>
Alternative treatments should only be considered under the guidance of a healthcare provider, particularly if traditional antibiotics aren’t suitable or effective. A combination of medical expertise and preventive measures can offer the best outcomes for managing UTIs.
<h2>Getting The Right Care With Everlywell</h2>
Treating a UTI effectively requires the right medication, proper dosage, and a commitment to completing the full course of antibiotics, even if symptoms improve before the medication is finished. Stopping treatment too early can allow bacteria to survive and potentially cause reinfection or lead to antibiotic resistance.
If you’re experiencing symptoms of a UTI and need fast, reliable support, Everlywell offers a convenient solution. With our online UTI treatment service, you can connect with certified healthcare providers, receive personalized care, and access prescription treatments like cephalexin — all without needing to leave your home.
Everlywell simplifies the process by offering discreet, effective, and timely care for UTIs, ensuring you get the treatment you need to feel better while supporting your long-term urinary health. Trusting a service like Everlywell can save you time, reduce the stress of in-person visits, and keep your focus on recovery. Want to get started? Learn more about Everlywell urinary tract infection treatment here.
References
- Kanafani Z. Twice daily cephalexin for uncomplicated urinary tract infection in women. Infectious Diseases Society of America. Published January 8, 2024. Accessed January 6, 2024. Medical Citation URL.
- Healthdirect Australia. Cefalexin (Cephalexin). Last reviewed April 2023. Accessed January 6, 2024. Medical Citation URL.
- Herman TF, Hashmi MF. Cephalexin. In: StatPearls. StatPearls Publishing; August 17, 2023.
- Drugs.com. Keflex dosage. Last updated May 2, 2024. Accessed January 6, 2024. Medical Citation URL.
- University of Illinois. What is cephalexin? Medical News Today. Updated August 16, 2024. Accessed January 6, 2024. Medical Citation URL.
- NHS.UK. Side effects of cefalexin. Last reviewed April 5, 2023. Accessed January 6, 2024. Medical Citation URL.
- Liu XD, Gao N, Qiao HL. Cephalosporin and penicillin cross-reactivity in patients allergic to penicillins. Int J Clin Pharmacol Ther. 2011;49(3):206-216. doi:10.5414/cpp49206
- Matzke GR, Aronoff GR, Atkinson AJ Jr, et al. Drug dosing consideration in patients with acute and chronic kidney disease-a clinical update from Kidney Disease: Improving Global Outcomes (KDIGO). Kidney Int. 2011;80(11):1122-1137. doi:10.1038/ki.2011.322
- Ghaswalla PK, Harpe SE, Tassone D, Slattum PW. Warfarin-antibiotic interactions in older adults of an outpatient anticoagulation clinic. Am J Geriatr Pharmacother. 2012;10(6):352-360. doi:10.1016/j.amjopharm.2012.09.006
- McCollum BJ, Garigan T, Earwood J. PURL: Can drinking more water prevent urinary tract infections? J Fam Pract. 2020;69(3):E19-E20.
- Abney SE, Bright KR, McKinney J, Ijaz MK, Gerba CP. Toilet hygiene-review and research needs. J Appl Microbiol. 2021;131(6):2705-2714. doi:10.1111/jam.15121
- Cambridge University Hospitals. Bladder care and management. Published May 19, 2023. Accessed January 6, 2024. Medical Citation URL.
- Jepson RG, Williams G, Craig JC. Cranberries for preventing urinary tract infections. Cochrane Database Syst Rev. 2012;10(10):CD001321. doi:10.1002/14651858.CD001321.pub5
- Department of Health. Urinary tract infections (UTI). Better Health Channel. Victoria State Government. Accessed January 6, 2024. Medical Citation URL.
- Schwenger EM, Tejani AM, Loewen PS. Probiotics for preventing urinary tract infections in adults and children. Cochrane Database Syst Rev. 2015;2015(12):CD008772. doi:10.1002/14651858.CD008772.pub2
- NHS.UK. About nitrofurantoin. Last reviewed January 7, 2022. Accessed January 6, 2024. Medical Citation URL.
- Falagas ME, Vouloumanou EK, Samonis G, Vardakas KZ. Fosfomycin. Clin Microbiol Rev. 2016;29(2):321-347. doi:10.1128/CMR.00068-15
- Lee BS, Bhuta T, Simpson JM, Craig JC. Methenamine hippurate for preventing urinary tract infections. Cochrane Database Syst Rev. 2012;10(10):CD003265. doi:10.1002/14651858.CD003265.pub3
- Wagenlehner F, Lorenz H, Ewald O, Gerke P. Why d-mannose may be as efficient as antibiotics in the treatment of acute uncomplicated lower urinary tract infections-preliminary considerations and conclusions from a non-interventional study. Antibiotics (Basel). 2022;11(3):314. doi:10.3390/antibiotics11030314