Cefalexin for infection
Keflex
Revisado por pares por Dr Colin Tidy, MRCGPÚltima actualización por Michael Stewart, MRPharmSLast updated 26 Nov 2024
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Before you take cefalexin, make sure your doctor knows if you have ever had an allergic reaction to an antibiotic.
Space out your doses evenly over the day and complete the full course.
The most common side effect of cefalexin is diarrhoea, which is usually mild and soon passes.
If diarrhoea becomes severe or lasts for more than 24 hours, you should speak with your doctor.
En este artículo:
Video picks for Medicamentos para el tratamiento de infecciones
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About cefalexin
Tipo de medicamento | Un antibiótico cefalosporínico |
Usado para | Treatment (and sometimes prevention) of infection |
También llamado | Cephalexin, Keflex® (USA) |
Disponible como | Capsules, tablets, and oral liquid medicine |
What is cefalexin used for?
Volver al contenidoCefalexin is a type of antibiotic used to treat bacterial infections such as urinary tract infections, skin infections, chest y garganta infections, recurrentes y dental infections.
It is suitable for adults and children and can be taken during pregnancy.
Some people who are allergic to penicillin antibiotics may not be able to take cefalexin, so make sure your doctor knows if you have ever had an allergic reaction to any other antibiotic.
Cefalexin treats an infection by killing the bacteria that are causing it.
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Side effects of cefalexin
Volver al contenidoCommon side effects of cefalexin are:
Diarrea.
Sentirse mal (náuseas).
Indigestión.
Dolor de estómago.
Candidiasis.
You will find a full list in the manufacturer's information leaflet supplied with the medicine.
Los efectos no deseados a menudo mejoran a medida que su cuerpo se adapta al nuevo medicamento, pero hable con su médico o farmacéutico si alguno de los siguientes persiste o se vuelve problemático.
How to manage cefalexin side effects
Volver al contenidoCefalexin side effects | ¿Qué puedo hacer si experimento esto? |
Diarrea | Drink plenty of water to replace the lost fluids. If the diarrhoea continues for longer than 24 hours, becomes severe, or contains blood, please let your doctor know de inmediato |
Indigestion, stomach ache, feeling sick | Mantente con alimentos simples. Si aún no lo estás haciendo, intenta tomar tus dosis después de las comidas |
Candidiasis | Speak with your doctor or pharmacist for advice |
Importante: if you develop an itchy rash, swollen face or mouth, or have difficulty breathing, these can be signs that you are allergic to the antibiotic. Do not take any more doses, and speak with your doctor or go to your local accident and emergency department straightaway.
If you experience any other symptoms which you think may be due to the antibiotic, please speak with your doctor or pharmacist for further advice.
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Who should not take cefalexin?
Volver al contenidoSome medicines are not suitable for people with certain conditions. Before starting cefalexin it is important that your doctor knows:
Si alguna vez ha tenido una reacción alérgica a un medicamento. Es particularmente importante que le informe a su médico si ha tenido una mala reacción a un antibiótico de penicilina o cefalosporina.
Si tienes algún problema con el funcionamiento de tus riñones.
If you are pregnant, trying for a baby or breastfeeding. Although cefalexin is not known to be harmful to babies, it is still important that you tell your doctor if you are expecting or breastfeeding a baby.
Si está tomando o usando otros medicamentos. Esto incluye cualquier medicamento que esté tomando y que esté disponible para comprar sin receta, así como medicamentos herbales y complementarios.
How to take cefalexin
Volver al contenidoRead the leaflet inside the pack before starting cefalexin. It explains how the antibiotic works and lists possible side effects.
Take cefalexin 2-4 times a day, as directed by your doctor. Check the label for your exact dose and timing.
For children: if using liquid cefalexin, carefully measure each dose as instructed.
Treatment usually lasts 5-7 days, but your doctor may adjust this. Always follow their advice.
For UTI prevention: you may take one dose daily, usually in the evening.
You can take cefalexin before or after food, but it may work a bit faster before meals.
Space doses evenly through the day and complete the full course, even if you feel better.
If you miss a dose, take it as soon as you remember. Do not take twice to make up for a missed one.
Obteniendo el máximo de tu tratamiento
Volver al contenidoTell your doctor or healthcare provider if you’re taking cefalexin before any operation or medical test, as it can affect some test results.
Antibiotics can sometimes cause thrush (oral o vaginal). If this happens, speak to your doctor or pharmacist.
If you take the contraceptive pill and have vomiting or diarrhoea for more than 24 hours while on antibiotics, the pill may be less effective. Ask your doctor or pharmacist about extra contraception. No extra precautions are needed if symptoms last less than 24 hours.
Cefalexin can stop the oral vacuna oral contra la fiebre tifoidea from working properly. Tell the person giving you any vaccines that you’re taking this antibiotic.
How to store cefalexin
Volver al contenidoMantenga todos los medicamentos fuera del alcance y la vista de los niños.
Store tablets and capsules in a cool, dry place, away from direct heat and light.
If you have been given liquid medicine, store it in a refrigerator. It will have been made up freshly by the pharmacy and lasts for 14 days, so please remember to check the expiry date, and do not use it after this date.
Información importante sobre todos los medicamentos
Volver al contenidoInformación importante sobre todos los medicamentos
No tome más de la dosis prescrita. Si sospecha que usted u otra persona podría haber tomado una sobredosis de este medicamento, acuda al departamento de accidentes y emergencias de su hospital local. Lleve el envase con usted, incluso si está vacío.
Este medicamento es para ti. Nunca lo des a otras personas, incluso si su condición parece ser la misma que la tuya.
Si compras algún medicamento, consulta con un farmacéutico que sea seguro tomarlo junto con tus otros medicamentos.
Si vas a someterte a una operación o a un tratamiento dental, informa a la persona que realiza el tratamiento sobre los medicamentos que estás tomando.
No guardes medicamentos caducados o no deseados. Llévalos a tu farmacia local, que se encargará de desecharlos por ti.
Si tienes alguna pregunta sobre este medicamento, consulta a tu farmacéutico.
Informar efectos secundarios de un medicamento o vacuna
Si experimenta efectos secundarios, puede reportarlos en línea a través de Yellow Card website.
Preguntas frecuentes
Volver al contenidoHow quickly does cefalexin work?
Cefalexin usually starts to work within an hour after taking the first dose. Most people notice improvement in symptoms, such as reduced pain, fever, or redness, within the first 1-2 days of treatment.
Is cefalexin safe to use during pregnancy?
Yes, cefalexin is considered safe to use during pregnancy as there is no evidence that it causes harm to the baby. However, always let your doctor or midwife know you are pregnant before taking cefalexin.
Does cefalexin contain penicillin?
No, cefalexin does not contain penicillin. However it is a cephalosporin antibiotic, which is chemically related to penicillin. People who are allergic to penicillin may also be allergic to cefalexin, so it is important to inform your doctor if you have a penicillin allergy before taking cefalexin.
Can you drink alcohol with cefalexin?
Yes, you can drink alcohol with cefalexin. However, it is advised to only drink in moderation as alcohol may increase side effects such as stomach upset, dizziness, or drowsiness.
Can cefalexin cause a rash?
Yes, cefalexin can cause a rash as a side effect and is usually a sign of an allergic reaction. If you develop a mild rash, contact your doctor for advice. If you have trouble breathing or swelling of the face, lips, tongue, or throat, seek medical help immediately.

¿Inseguro sobre mezclar medicamentos?
Verifica posibles interacciones entre medicamentos, suplementos y alimentos antes de tomarlos juntos.
Lecturas adicionales y referencias
- Manufacturer's PIL, Cefalexin 250 mg and 500 mg Capsules; Aurobindo Pharma - Milpharm Ltd; The electronic Medicines Compendium. Dated August 2024.
- Manufacturer's PIL, Cefalexin 125 mg and 250 mg/5 ml Powder for Oral Suspension; Aurobindo Pharma - Milpharm Ltd; The electronic Medicines Compendium. Dated March 2024.
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Historial del artículo
La información en esta página está escrita y revisada por pares por clínicos calificados.
Next review due: 26 Nov 2027
26 Nov 2024 | Última versión

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