Medically reviewed by Jessica Swirble, PharmD
Last updated on March 27, 2025
Drug Information | Side Effects | Use & Dosage | Request an Online Prescription
Cephalexin is an antibiotic medication used to treat bacterial infections.
Cephalexin is prescribed to treat bacterial infections in several areas of the body. It is prescribed to treat pneumonia and bacterial respiratory infections. It is also prescribed to treat infections of the bones, ears, skin, and urinary tract infections. It is effective against bacterial infections but not viral, parasitic, or fungal infections.
Cephalexin is a cephalosporin antibiotic. It kills bacteria that cause infections by inhibiting cell wall synthesis.
Cephalexin is supplied as an oral tablet, capsule, or liquid solution. It should be taken by mouth with or without food.
The time it takes to note the effects of cephalexin will vary depending on the patient and the severity of the condition being treated. Most patients start feeling better within a few days after starting use. In the case of a severe infection, it may take longer before you feel better.
If you have been taking cephalexin for several days and aren't feeling better, talk to your healthcare provider. Do not increase your dosage. If you are feeling better, do not stop using cephalexin until your provider directs you to do so.
Take cephalexin for as long as your provider tells you to.
Cephalexin may be prescribed off-label for:
Talk to your healthcare provider about other uses for this medication, if appropriate.
Cephalexin is available as an oral capsule, tablet, or liquid. It should be taken by mouth.
It is available in its generic form.
Cephalexin is only available via prescription. You must have a written prescription from a licensed healthcare provider to obtain this medication.
The use of cephalexin has been shown to cause side effects in some patients.
Common mild side effects of cephalexin use include:
More severe side effects include:
Seek medical attention immediately if you experience any severe symptoms while taking cephalexin. If you experience mild side effects that become severe or do not go away after a few days, speak to a healthcare provider right away.
Tell your healthcare provider about any existing medical conditions, allergies, or other medications you are taking before starting treatment with cephalexin. This includes prescription drugs, over-the-counter medications, and dietary supplements, as they may interact with this drug.
Tell your provider if you are taking these medications or supplements:
You should also mention medical conditions such as:
If you are pregnant, planning to become pregnant, or breastfeeding, consult your healthcare provider before using cephalexin to assess potential risks and benefits.
You can follow your regular diet while taking cephalexin. Talk to your healthcare provider about the use of this drug with food, beverages, alcohol, and tobacco.
Your healthcare provider will tell you if you should avoid certain foods, beverages, or products while using cephalexin. It is extremely important to follow their guidance, as certain drugs can interact with other substances in the body---leading to potentially severe reactions. If you have any questions about special instructions you should follow while taking this drug, talk to your healthcare provider before use.
The symptoms of a cephalexin overdose include:
If you experience any of these symptoms, call the poison control helpline at 1-800-222-1222. If an individual has collapsed, is having seizures, or is unresponsive, call 9-1-1 immediately.
Cephalexin is available in the following forms:
The typical starting dose of cephalexin varies depending on the type of infection being treated, its severity, and individual patient factors. It is important to follow your healthcare provider's instructions regarding dosage and administration.
For uncomplicated skin and soft tissue infections, the typical starting dose may be:
For urinary tract infections (UTIs), the typical starting dose may be:
For respiratory tract infections, such as pneumonia, your healthcare provider may prescribe higher doses and longer treatment durations.
Your healthcare provider will determine the most appropriate dose and duration of treatment based on your medical history, current medications, and response to the medication.
Cephalexin should be taken exactly as prescribed by your healthcare provider. Do not exceed the recommended dose or duration of treatment without consulting your provider.
If you have any questions about your dosage, contact your healthcare provider. If you want to talk to a provider right away, book an online doctor appointment on Sesame to discuss your concerns.
If you miss a dose, take it as soon as you remember it. If it's almost time for another dose of cephalexin, skip the missed dose and take your next dose as scheduled. Do not take or apply a double dose of cephalexin.
Do not discontinue or alter your cephalexin dosage without consulting with your healthcare provider. Follow your healthcare provider's instructions regarding dosing and other recommendations for taking cephalexin.
Store cephalexin as directed by your healthcare provider or pharmacist. Proper storage is essential to maintain the medication's effectiveness. Cephalexin should be stored at room temperature, away from excessive heat, light, and moisture.
Keep the medication out of the reach of children and ensure that the container is tightly closed.