Cephalexin
Cephalexin is used to treat bacterial infections including skin, respiratory, and urinary tract infections. It is available as Keflex and is commonly prescribed in the antibiotics category.
About Cephalexin
Cephalexin is a first-generation cephalosporin antibiotic also known by the brand name Keflex. It is primarily used to is prescribed to treat: • Bacterial infections including skin, respiratory, and urinary tract infections • Various related conditions in the antibiotics category • Associated symptoms and complications It is an important medication that helps manage these conditions effectively. Cephalexin is available in oral capsule (250 mg, 500 mg, 750 mg), oral tablet (250 mg, 500 mg), and oral suspension (125 mg/5 ml, 250 mg/5 ml) form. Healthcare providers commonly prescribe Cephalexin for conditions including Attention Deficit Hyperactivity Disorder (ADHD), Lupus Anticoagulant, and Vertigo.
Cephalexin at a Glance
- Brand names
- Keflex
- Drug class
- First-Generation Cephalosporin Antibiotic
- Pregnancy category
- FDA Category Category B — Animal studies have not shown evidence of fetal harm, and observational human data have not demonstrated an increased risk of major birth defects. Cephalexin is generally considered safe across all trimesters when clinically indicated, including for urinary tract infections and Group B Streptococcus prophylaxis.
- Available forms
- Oral capsule (250 mg, 500 mg, 750 mg), Oral tablet (250 mg, 500 mg), Oral suspension (125 mg/5 mL, 250 mg/5 mL)
- Therapeutic categories
- Antibiotics, Cephalosporins, Infectious Disease
- Conditions treated
- 3 related conditions on this site
What Cephalexin Is Used For
is prescribed to treat:
• Bacterial infections including skin, respiratory, and urinary tract infections • Various related conditions in the antibiotics category • Associated symptoms and complications
It is an important medication that helps manage these conditions effectively.
Dosage Quick Reference
These are general dosage guidelines for Cephalexin. Your doctor will determine the appropriate dose for your specific situation.
| Condition | Starting Dose | Maintenance Dose |
|---|---|---|
| Uncomplicated cystitis (urinary tract infection) | 500 mg every 12 hours | 500 mg every 12 hours for 5–7 days |
| Skin and soft tissue infection (mild-to-moderate) | 500 mg every 6 hours | 500 mg every 6 hours for 7–14 days |
| Streptococcal pharyngitis | 500 mg every 12 hours | 500 mg every 12 hours for 10 days |
| Acute otitis media (children) | 25–50 mg/kg/day divided every 6–12 hours | Continue same dose for 7–10 days |
| Endocarditis prophylaxis (dental procedures) | 2 g single dose 30–60 min before procedure | Single dose only |
Side Effects
Common side effects may include:
• Nausea or stomach upset • Headache • Dizziness or lightheadedness • Fatigue or tiredness • Mild rash or itching
Serious side effects (seek immediate medical attention):
• Severe allergic reactions (rash, hives, swelling, difficulty breathing) • Unusual bleeding or bruising • Severe stomach pain • Signs of liver problems (yellowing of skin/eyes, dark urine) • Chest pain or irregular heartbeat • Severe dizziness or fainting • Signs of serious adverse effects
See also: Drug Interactions ↓
Drug Interactions
Cephalexin has a relatively low potential for clinically significant drug interactions, but a few are worth recognizing.
- Probenecid: Inhibits the renal tubular secretion of cephalexin, raising and prolonging its plasma concentration. This combination is occasionally used intentionally to extend antibiotic exposure but should be avoided when high cephalexin levels are not desired.
- Metformin: Cephalexin can increase metformin plasma concentrations through competition for renal cation transporters, potentially raising the risk of lactic acidosis in patients with impaired kidney function. Monitor for metformin-related side effects in patients with reduced renal clearance.
- Warfarin: Although less commonly than with broader-spectrum antibiotics, cephalexin may modestly enhance the anticoagulant effect of warfarin by altering gut flora that synthesize vitamin K. Check INR within a week of starting therapy.
- Oral typhoid vaccine (live): Antibiotics may inactivate the live attenuated bacteria in the oral typhoid vaccine. Separate administration by at least 24 hours after the last antibiotic dose.
- Loop diuretics and aminoglycosides: When cephalexin is combined with these nephrotoxic agents, monitor renal function more closely, particularly in older adults and patients with baseline kidney impairment.
See also: Questions to Ask Your Doctor ↓
Key Considerations
Known drug interactions
Cephalexin has documented interactions with other medications, supplements, and certain foods. Review the Drug Interactions section below and tell your healthcare provider about every medication you take, including over-the-counter products. Jump to section →
Multiple forms available
Cephalexin comes in more than one form (Oral capsule (250 mg, 500 mg, 750 mg), Oral tablet (250 mg, 500 mg), Oral suspension (125 mg/5 mL, 250 mg/5 mL)). The right form for you depends on your condition, ease of use, and your provider's recommendation.
Additional Information
What is ?
Cephalexin (generic name: Cephalexin) is a medication primarily used to treat bacterial infections including skin, respiratory, and urinary tract infections. It is marketed under the brand name(s) Keflex and belongs to the Antibiotics category of medications.
How Does Cephalexin Work?
Cephalexin works through several mechanisms to provide therapeutic benefits:
- Acts on specific receptors or pathways in the body
- Modulates biological processes related to the treated condition
- Provides symptom relief and improves quality of life
- Helps manage the underlying condition effectively
- Works best when combined with appropriate lifestyle modifications
The medication is designed to target the specific pathways involved in bacterial infections including skin, respiratory, and urinary tract infections, making it an effective treatment option.
Common Uses
Primary Indications
Cephalexin is commonly prescribed for:
- Bacterial infections including skin, respiratory, and urinary tract infections: The main indication for this medication
- Related Conditions: Associated symptoms and complications
- Prevention: May help prevent progression of certain conditions
- Symptom Management: Reduces discomfort and improves daily function
Additional Uses
In some cases, Cephalexin may also be prescribed for:
- Off-label uses as determined by your healthcare provider
- Combination therapy with other medications
- Long-term management of chronic conditions
- Short-term treatment of acute symptoms
Dosage and Administration
Cephalexin dosing varies based on the specific condition being treated and individual patient factors.
Typical Dosing:
- Starting dose is typically determined by your healthcare provider
- May be adjusted based on response and tolerability
- Can be taken with or without food (follow specific instructions)
- Usually taken once or twice daily
Administration Tips:
- Take at the same time(s) each day for best results
- Swallow tablets/capsules whole unless instructed otherwise
- Don't skip doses
- Complete full course of treatment as prescribed
- Follow your doctor's specific instructions carefully
Important Safety Information
Who Should Not Take Cephalexin?
Do not take Cephalexin if you:
- Are allergic to Cephalexin or any ingredients
- Have certain medical conditions (discuss with your doctor)
- Are taking medications that interact with Cephalexin
- Have severe liver or kidney disease (without dose adjustment)
Drug Interactions
Inform your doctor about all medications you take, including:
- Prescription medications
- Over-the-counter drugs
- Vitamins and supplements
- Herbal products
Some medications may interact with Cephalexin, affecting its efficacy or increasing side effect risk.
Pregnancy and Breastfeeding
Pregnancy:
- Discuss risks and benefits with your doctor if pregnant or planning pregnancy
- May require special monitoring or dose adjustments
- Some medications should be avoided during pregnancy
Breastfeeding:
- Consult your doctor about safety while breastfeeding
- May pass into breast milk
- Benefits and risks should be carefully considered
Monitoring and Follow-Up
While taking Cephalexin, your doctor may monitor:
- Effectiveness of treatment (symptom improvement)
- Side effects or adverse reactions
- Laboratory values if applicable
- Blood pressure, heart rate, or other vital signs as appropriate
- Overall response to therapy
Regular follow-up appointments are important to ensure the medication is working properly and to make any necessary adjustments.
Managing Side Effects
Most side effects are mild and improve with time. Here are strategies for common side effects:
Gastrointestinal Upset
- Take with food if allowed
- Stay well hydrated
- Eat smaller, more frequent meals
- Report persistent nausea or vomiting
Dizziness
- Rise slowly from sitting or lying positions
- Avoid sudden movements
- Stay hydrated
- Avoid alcohol
- Report severe or persistent dizziness
Fatigue
- Get adequate rest
- Maintain regular sleep schedule
- Exercise as tolerated
- Report excessive tiredness that interferes with daily activities
Lifestyle Considerations
To maximize the benefits of Cephalexin:
- Follow a healthy, balanced diet
- Exercise regularly as recommended by your doctor
- Maintain a healthy weight
- Avoid alcohol or limit consumption
- Don't smoke
- Manage stress through relaxation techniques
- Get adequate sleep
- Stay well hydrated
- Keep all follow-up appointments
- Take medication consistently as prescribed
When to Contact Your Doctor
Seek immediate medical attention if you experience:
- Signs of severe allergic reaction (difficulty breathing, severe rash, swelling)
- Chest pain or rapid heartbeat
- Severe dizziness or fainting
- Unusual bleeding or bruising
- Signs of liver problems (yellowing of skin/eyes, dark urine, severe fatigue)
- Severe stomach pain
- Any symptoms that concern you
Contact your doctor for non-emergency issues:
- Mild to moderate side effects that persist
- Questions about your medication
- Concerns about effectiveness
- New medications prescribed by another doctor
- Scheduled surgery or dental procedures
- Planning pregnancy
Storage
Store Cephalexin at room temperature (68-77°F or 20-25°C) away from light, heat, and moisture. Keep in original container. Keep out of reach of children and pets. Do not use past expiration date.
Important Reminders
- Take exactly as prescribed by your doctor
- Don't stop suddenly without medical advice
- Keep all follow-up appointments
- Report any unusual symptoms
- Don't share medication with others
- Store safely away from children
- Check expiration dates
- Ask your pharmacist if you have questions
Clinical Benefits
When used appropriately, Cephalexin provides several benefits:
- Effective management of bacterial infections including skin, respiratory, and urinary tract infections
- Improvement in quality of life
- Reduction in symptoms
- Prevention of complications
- Generally well-tolerated when used as directed
- Backed by clinical research and extensive use
Disclaimer: This information is for educational purposes only and is not intended to replace professional medical advice, diagnosis, or treatment. Always consult your physician or other qualified healthcare provider with any questions about a medical condition or medication.
Frequently Asked Questions
Questions to Ask Your Doctor About Cephalexin
Consider discussing these topics at your next appointment:
- Is cephalexin the most appropriate antibiotic for my specific infection?
- Given my penicillin allergy history, is it safe for me to take a cephalosporin?
- How will we know if the infection is responding, and when should I follow up?
- Should I take a probiotic alongside cephalexin to reduce the risk of diarrhea?
- What symptoms should make me stop the medication and call your office?
Medical Disclaimer: This information is for educational purposes only and should not be considered medical advice. Always consult with your healthcare provider before starting, stopping, or changing any medication. Your doctor can provide personalized recommendations based on your specific health condition and medical history.