Cephalexin 750mg Capsules
It is used to treat bacterial infections.
Drug Class
Antibiotic
Pharmacologic Class
First-generation Cephalosporin
Pregnancy Category
Category B
FDA Approved
Jan 1971
DEA Schedule
Not Controlled
Overview
What is this medicine?
Cephalexin is an antibiotic that belongs to a group of medicines called cephalosporins. It works by stopping the growth of bacteria. It is used to treat various bacterial infections, such as infections of the skin, bones, ears, throat, and urinary tract. It will not work for viral infections like the common cold or flu.
How to Use This Medicine
Taking Your Medication
To use this medication correctly, follow your doctor's instructions and read all the information provided. Take your medication as directed, with or without food. If you experience stomach upset, taking it with food may help. Continue using the medication even if your symptoms improve.
Storing and Disposing of Your Medication
Store your medication at room temperature in a dry place, avoiding the bathroom. Keep all medications in a safe location, out of the reach of children and pets. Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so. If you have questions about disposal, consult your pharmacist. You may also have access to drug take-back programs in your area.
Missing a Dose
If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next dose, skip the missed dose and resume your regular schedule. Do not take two doses at the same time or take extra doses.
To use this medication correctly, follow your doctor's instructions and read all the information provided. Take your medication as directed, with or without food. If you experience stomach upset, taking it with food may help. Continue using the medication even if your symptoms improve.
Storing and Disposing of Your Medication
Store your medication at room temperature in a dry place, avoiding the bathroom. Keep all medications in a safe location, out of the reach of children and pets. Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so. If you have questions about disposal, consult your pharmacist. You may also have access to drug take-back programs in your area.
Missing a Dose
If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next dose, skip the missed dose and resume your regular schedule. Do not take two doses at the same time or take extra doses.
Lifestyle & Tips
- Take the medication exactly as prescribed by your doctor, even if you start to feel better. Do not skip doses or stop taking it early, as this can lead to antibiotic resistance and a return of the infection.
- Cephalexin can be taken with or without food. If it causes stomach upset, take it with food or milk.
- Drink plenty of fluids while taking this medication.
- Avoid alcohol consumption, as it may worsen gastrointestinal side effects.
- If you are taking oral contraceptives, discuss with your doctor as antibiotic use may rarely decrease their effectiveness. Consider using an alternative birth control method during treatment.
- Store at room temperature away from moisture and heat.
Available Forms & Alternatives
Available Strengths:
- Cephalexin 250mg/5ml Susp 100ml
- Cephalexin 250mg/5ml Susp 200ml
- Cephalexin 125mg/5ml Susp 100ml
- Cephalexin 125mg/5ml Susp 200ml
- Cephalexin 250mg Capsules
- Cephalexin 500mg Capsules
- Cephalexin 250mg Tablets
- Cephalexin 500mg Tablets
- Cephalexin 750mg Capsules
- Cephalexin 125mg/5ml Susp 100ml
- Cephalexin 500mg Tablets
- Cephalexin 250mg Tablets
Dosing & Administration
Adult Dosing
Standard Dose:
750 mg every 12 hours for most infections (e.g., skin and soft tissue, pharyngitis/tonsillitis). For severe infections or bone infections, up to 1 g every 6 hours.
Dose Range:
250 - 1000 mg
Condition-Specific Dosing:
mildToModerateInfections:
250 mg every 6 hours or 500 mg every 12 hours
severeInfections:
500 mg every 6 hours or 1 g every 12 hours
skinAndSoftTissueInfections:
500 mg every 12 hours or 750 mg every 12 hours
streptococcalPharyngitis:
250 mg every 6 hours or 500 mg every 12 hours for 10 days
boneInfections:
250 mg to 1 g every 6 hours
Pediatric Dosing
Neonatal:
Not established (use caution, consult specific guidelines)
Infant:
25-50 mg/kg/day in divided doses (every 6 or 12 hours); up to 100 mg/kg/day for severe infections. Max 4 g/day.
Child:
25-50 mg/kg/day in divided doses (every 6 or 12 hours); up to 100 mg/kg/day for severe infections. Max 4 g/day.
Adolescent:
Adult dosing may apply if weight > 40 kg, otherwise pediatric mg/kg dosing.
Dose Adjustments
Renal Impairment:
Mild:
CrCl 30-59 mL/min: No adjustment typically needed for standard doses, but consider extending interval to every 8-12 hours for higher doses.
Moderate:
CrCl 15-29 mL/min: 250 mg every 8-12 hours or 500 mg every 12 hours.
Severe:
CrCl <15 mL/min: 250 mg every 12-24 hours or 500 mg every 24 hours.
Dialysis:
Hemodialysis: 250 mg to 500 mg after each dialysis session. Peritoneal Dialysis: 250 mg every 12 hours or 500 mg every 24 hours.
Confidence:
High
Hepatic Impairment:
Mild:
No adjustment needed.
Moderate:
No adjustment needed.
Severe:
No adjustment needed.
Confidence:
High
Pharmacology
Mechanism of Action
Cephalexin is a bactericidal antibiotic that inhibits bacterial cell wall synthesis by binding to one or more of the penicillin-binding proteins (PBPs). This inhibits the final transpeptidation step of peptidoglycan synthesis in the bacterial cell wall, leading to inhibition of cell wall biosynthesis and eventually bacterial cell lysis.
Pharmacokinetics
Absorption:
Bioavailability:
Approximately 90-100%
Tmax:
Oral: 1 hour (fasting)
FoodEffect:
Food may delay absorption but does not significantly affect the total amount absorbed.
Distribution:
Vd:
Approximately 0.26 L/kg
ProteinBinding:
Approximately 10-15%
CnssPenetration:
Limited (does not achieve therapeutic concentrations in CSF unless meninges are inflamed)
Elimination:
HalfLife:
0.5-1.2 hours (normal renal function); significantly prolonged in renal impairment (e.g., 5-30 hours in severe renal failure)
Clearance:
Renal clearance is approximately 210-300 mL/min
ExcretionRoute:
Renal (glomerular filtration and tubular secretion)
Unchanged:
Approximately 70-90% excreted unchanged in urine within 8 hours
Pharmacodynamics
OnsetOfAction:
Rapid (within 1 hour for measurable plasma concentrations)
PeakEffect:
1 hour (plasma concentration)
DurationOfAction:
Dependent on dosing interval, typically maintains therapeutic levels for 6-12 hours based on dosing frequency.
Confidence:
Medium
Safety & Warnings
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
While rare, some people may experience severe and potentially life-threatening side effects when taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin (with or without fever)
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of a severe skin reaction (Stevens-Johnson syndrome/toxic epidermal necrolysis), such as:
+ Red, swollen, blistered, or peeling skin (with or without fever)
+ Red or irritated eyes
+ Sores in the mouth, throat, nose, or eyes
Signs of liver problems, including:
+ Dark urine
+ Tiredness
+ Decreased appetite
+ Upset stomach or stomach pain
+ Light-colored stools
+ Vomiting
+ Yellow skin or eyes
Fever, chills, or sore throat
Unexplained bruising or bleeding
Feeling extremely tired or weak
Confusion
Hallucinations (seeing or hearing things that are not there)
Difficulty urinating or changes in urine output
Seizures
Severe dizziness
Severe headache
Severe joint pain
Vaginal itching or discharge
Antibiotic-Associated Diarrhea
Diarrhea is a common side effect of antibiotics. In rare cases, a severe form of diarrhea called C. diff-associated diarrhea (CDAD) may occur. This condition can lead to a life-threatening bowel problem. If you experience any of the following symptoms, contact your doctor immediately:
Stomach pain
Cramps
Very loose, watery, or bloody stools
Do not treat diarrhea without consulting your doctor.
Other Possible Side Effects
Like all medications, this drug can cause side effects. Many people experience no side effects or only mild ones. If you notice any of the following side effects or any other unusual symptoms, contact your doctor:
Stomach pain or diarrhea
* Upset stomach or vomiting
This is not an exhaustive list of possible side effects. If you have questions or concerns, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
While rare, some people may experience severe and potentially life-threatening side effects when taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin (with or without fever)
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of a severe skin reaction (Stevens-Johnson syndrome/toxic epidermal necrolysis), such as:
+ Red, swollen, blistered, or peeling skin (with or without fever)
+ Red or irritated eyes
+ Sores in the mouth, throat, nose, or eyes
Signs of liver problems, including:
+ Dark urine
+ Tiredness
+ Decreased appetite
+ Upset stomach or stomach pain
+ Light-colored stools
+ Vomiting
+ Yellow skin or eyes
Fever, chills, or sore throat
Unexplained bruising or bleeding
Feeling extremely tired or weak
Confusion
Hallucinations (seeing or hearing things that are not there)
Difficulty urinating or changes in urine output
Seizures
Severe dizziness
Severe headache
Severe joint pain
Vaginal itching or discharge
Antibiotic-Associated Diarrhea
Diarrhea is a common side effect of antibiotics. In rare cases, a severe form of diarrhea called C. diff-associated diarrhea (CDAD) may occur. This condition can lead to a life-threatening bowel problem. If you experience any of the following symptoms, contact your doctor immediately:
Stomach pain
Cramps
Very loose, watery, or bloody stools
Do not treat diarrhea without consulting your doctor.
Other Possible Side Effects
Like all medications, this drug can cause side effects. Many people experience no side effects or only mild ones. If you notice any of the following side effects or any other unusual symptoms, contact your doctor:
Stomach pain or diarrhea
* Upset stomach or vomiting
This is not an exhaustive list of possible side effects. If you have questions or concerns, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- Severe allergic reaction (anaphylaxis): difficulty breathing, swelling of face/throat, severe rash, dizziness.
- Severe diarrhea (watery or bloody stools), abdominal cramps, or fever, which may indicate Clostridioides difficile-associated diarrhea (CDAD). This can occur during or even weeks after treatment.
- New or worsening rash, itching, or hives.
- Unusual bleeding or bruising.
- Yellowing of the skin or eyes (jaundice).
- Dark urine or pale stools.
- Signs of kidney problems: change in amount of urine, swelling in feet or ankles.
- Signs of liver problems: nausea, vomiting, loss of appetite, unusual tiredness.
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the symptoms you experienced.
If you are currently taking probenecid, as this may interact with the medication.
Additionally, to ensure safe treatment, provide your doctor and pharmacist with a comprehensive list of:
All prescription and over-the-counter (OTC) medications you are taking
Any natural products or vitamins you are using
* Your existing health problems
This will help your doctor determine if it is safe to take this medication with your other medications and health conditions. Never start, stop, or adjust the dose of any medication without first consulting your doctor.
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the symptoms you experienced.
If you are currently taking probenecid, as this may interact with the medication.
Additionally, to ensure safe treatment, provide your doctor and pharmacist with a comprehensive list of:
All prescription and over-the-counter (OTC) medications you are taking
Any natural products or vitamins you are using
* Your existing health problems
This will help your doctor determine if it is safe to take this medication with your other medications and health conditions. Never start, stop, or adjust the dose of any medication without first consulting your doctor.
Precautions & Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. If you are taking this drug for an extended period, your doctor may recommend regular blood tests to monitor your condition.
If you have diabetes and regularly test your urine for glucose, consult with your doctor to determine the most suitable testing method for you, as this medication may affect the results.
Additionally, be aware that this drug can influence the outcome of certain laboratory tests. Therefore, it is crucial to notify all your healthcare providers and laboratory personnel that you are taking this medication.
Do not use this medication for longer than prescribed, as this can increase the risk of developing a second infection.
If you are pregnant, planning to become pregnant, or are breastfeeding, it is vital to discuss the potential benefits and risks of this medication with your doctor to ensure the best possible outcome for you and your baby.
If you have diabetes and regularly test your urine for glucose, consult with your doctor to determine the most suitable testing method for you, as this medication may affect the results.
Additionally, be aware that this drug can influence the outcome of certain laboratory tests. Therefore, it is crucial to notify all your healthcare providers and laboratory personnel that you are taking this medication.
Do not use this medication for longer than prescribed, as this can increase the risk of developing a second infection.
If you are pregnant, planning to become pregnant, or are breastfeeding, it is vital to discuss the potential benefits and risks of this medication with your doctor to ensure the best possible outcome for you and your baby.
Overdose Information
Overdose Symptoms:
- Nausea
- Vomiting
- Epigastric distress
- Diarrhea
- Hematuria (blood in urine)
- Rarely, seizures (especially in patients with renal impairment)
What to Do:
In case of suspected overdose, seek immediate medical attention or call a poison control center (e.g., 1-800-222-1222). Treatment is primarily supportive, including gastric lavage or activated charcoal if ingestion is recent. Hemodialysis may be useful in severe cases, especially with renal impairment.
Drug Interactions
Major Interactions
- Metformin (increased metformin plasma concentrations, risk of lactic acidosis)
- Probenecid (decreased renal excretion of cephalexin, increased cephalexin levels)
Moderate Interactions
- Oral Contraceptives (potential for reduced efficacy, though less evidence for cephalosporins than penicillins)
- Warfarin (rarely, enhanced anticoagulant effect due to gut flora alteration)
- Live Bacterial Vaccines (e.g., Typhoid vaccine - may reduce therapeutic effect of vaccine)
Confidence Interactions
Monitoring
Baseline Monitoring
Renal function (BUN, creatinine)
Rationale: Cephalexin is primarily renally eliminated; baseline assessment is crucial for dose adjustment in patients with pre-existing renal impairment.
Timing: Prior to initiation of therapy, especially in elderly or those with suspected renal dysfunction.
Routine Monitoring
Signs and symptoms of superinfection (e.g., oral thrush, vaginal yeast infection, C. difficile-associated diarrhea)
Frequency: Throughout therapy and for several weeks post-therapy
Target: Absence of new infections
Action Threshold: Development of new or worsening symptoms; discontinue cephalexin and initiate appropriate therapy.
Complete Blood Count (CBC) with differential
Frequency: Periodically, especially during prolonged therapy (e.g., >2 weeks)
Target: Within normal limits
Action Threshold: Significant changes (e.g., eosinophilia, leukopenia, thrombocytopenia) may indicate drug-induced hypersensitivity or bone marrow suppression.
Liver function tests (ALT, AST, bilirubin)
Frequency: Periodically, especially during prolonged therapy or in patients with pre-existing liver disease (though hepatic metabolism is minimal)
Target: Within normal limits
Action Threshold: Significant elevations may indicate drug-induced liver injury (rare).
Symptom Monitoring
- Rash
- Hives
- Itching
- Swelling (face, lips, tongue, throat)
- Difficulty breathing or swallowing
- Severe diarrhea (especially watery or bloody)
- Abdominal pain or cramping
- Fever
- Sore throat
- Unusual bleeding or bruising
- Yellowing of skin or eyes (jaundice)
- Dark urine
- Unusual tiredness or weakness
Special Patient Groups
Pregnancy
Cephalexin is generally considered safe for use during pregnancy (Pregnancy Category B). Animal reproduction studies have not demonstrated a risk to the fetus, and there are no adequate and well-controlled studies in pregnant women. It should be used during pregnancy only if clearly needed.
Trimester-Specific Risks:
First Trimester:
No increased risk of major birth defects observed in human studies.
Second Trimester:
Generally considered safe.
Third Trimester:
Generally considered safe.
Lactation
Cephalexin is excreted in human milk in low concentrations. It is generally considered compatible with breastfeeding (Lactation Risk L1). Monitor breastfed infants for potential adverse effects such as diarrhea, candidiasis (thrush, diaper rash), or allergic reactions (e.g., rash).
Infant Risk:
Low risk. Potential for minor gastrointestinal upset or sensitization in the infant.
Pediatric Use
Cephalexin is widely used and generally well-tolerated in pediatric patients. Dosing is weight-based. Caution should be exercised in neonates and infants due to immature renal function, which may prolong half-life. Close monitoring for adverse effects is recommended.
Geriatric Use
No specific dose adjustment is required based solely on age. However, elderly patients are more likely to have age-related decline in renal function, which necessitates careful assessment of creatinine clearance and appropriate dose adjustment to prevent accumulation and toxicity. Monitor for signs of C. difficile-associated diarrhea.
Clinical Information
Clinical Pearls
- Cephalexin is a first-generation cephalosporin, primarily active against Gram-positive bacteria (e.g., Staphylococcus aureus, Streptococcus pyogenes) and some Gram-negative bacteria (e.g., E. coli, Klebsiella pneumoniae, Proteus mirabilis). It is not effective against MRSA or Pseudomonas aeruginosa.
- It is a common choice for skin and soft tissue infections, uncomplicated urinary tract infections, and streptococcal pharyngitis.
- Advise patients to complete the full course of therapy, even if symptoms improve, to prevent the development of antibiotic resistance.
- Oral suspension should be shaken well before each use and stored in the refrigerator. Discard any unused portion after 14 days.
- Patients with a history of severe hypersensitivity (e.g., anaphylaxis) to penicillin should generally avoid cephalexin due to potential cross-reactivity, although the risk is low (1-10%).
- May cause a false-positive urine glucose test with Benedict's solution or Fehling's solution, but not with enzyme-based tests.
Alternative Therapies
- Amoxicillin (for susceptible infections)
- Dicloxacillin (for staphylococcal skin infections)
- Cefadroxil (another first-generation cephalosporin, often dosed once or twice daily)
- Clindamycin (for skin/soft tissue infections, especially if penicillin allergy or MRSA concern)
- Macrolides (e.g., Azithromycin, Clarithromycin - for respiratory tract infections, some skin infections, if susceptible)
- Trimethoprim/Sulfamethoxazole (for UTIs, some skin infections)
- Doxycycline (for some skin infections, respiratory infections)
Cost & Coverage
Average Cost:
$15 - $50 per 30 capsules (750mg)
Generic Available:
Yes
Insurance Coverage:
Tier 1 (Preferred Generic) or Tier 2 (Non-Preferred Generic) on most formularies.
General Drug Facts
If your symptoms or health issues persist or worsen, it's essential to contact your doctor for further guidance. To ensure your safety, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so be sure to check with your pharmacist for more information. If you have any questions or concerns about your medication, don't hesitate to reach out to your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When seeking help, be prepared to provide details about the medication taken, including the amount and time of ingestion.