On this page · 10 sections
Penicillinase resistant penicillins oral capsule (250 mg; 500 mg)

Dicloxacillin

Generic name: dicloxacillin

Brand names: Dycill, Dynapen

Last updated November 2, 2026 0 views
Share

What is dicloxacillin?

Dicloxacillin is a penicillin antibiotic that helps fight bacteria in your body.

Dicloxacillin is used to treat various types of infections caused by bacteria, including bronchitis, pneumonia, and staphylococcal (or "staph") infections.

Dicloxacillin may also be used for reasons not mentioned in this medication guide.

This section was rewritten for readability and reviewed for meaning.

How should I take dicloxacillin?

Follow all directions on your prescription label. Do not take this medicine in larger or smaller amounts or for longer than recommended.

Take dicloxacillin on an empty stomach, at least 1 hour before or 2 hours after a meal.

Take this medicine with a full glass of water. To avoid heartburn or stomach irritation, do not take dicloxacillin while you are lying down or getting ready for bed.

While using dicloxacillin, you may need frequent medical tests.

This medicine can cause unusual results with certain medical tests. Tell any doctor who treats you that you are using dicloxacillin.

Use this medicine for the full prescribed length of time. Your symptoms may improve before the infection is completely cleared. Skipping doses may also increase your risk of further infection that is resistant to antibiotics. Dicloxacillin will not treat a viral infection such as the flu or a common cold.

Do not share this medicine with another person, even if they have the same symptoms you have.

Store at room temperature away from moisture, heat, and light.

This section was rewritten for readability and reviewed for meaning.

Warnings

Follow all instructions on your medicine label and package. Inform each of your healthcare providers about all your medical conditions, allergies, and all medicines you are taking.

This section was rewritten for readability and reviewed for meaning.

Before taking this medicine

You should not use dicloxacillin if you are allergic to dicloxacillin or to any other penicillin antibiotic, such as:

  • amoxicillin;
  • ampicillin;
  • carbenicillin;
  • oxacillin; or
  • penicillin.

To make sure dicloxacillin is safe for you, tell your doctor if you have:

  • asthma;
  • a stomach illness (nausea, vomiting, digestive problems);
  • liver disease;
  • kidney disease;
  • a bleeding or blood clotting disorder;
  • a history of diarrhea caused by taking antibiotics; or
  • a history of any type of allergy (especially cephalosporins such as Ceclor, Ceftin, Duricef, Keflex, and others).

It is not known whether this medicine will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

Dicloxacillin can make birth control pills less effective. Ask your doctor about using a non-hormonal birth control (condom, diaphragm with spermicide) to prevent pregnancy.

Dicloxacillin can pass into breast milk and may harm a nursing baby. Tell your doctor if you are breast-feeding a baby.

Do not give this medicine to a child without medical advice.

This section was rewritten for readability and reviewed for meaning.

Dicloxacillin side effects

Get emergency medical help if you have signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Dicloxacillin may cause serious side effects. Call your doctor right away if you have:

  • severe stomach pain, diarrhea that is watery or bloody;
  • nausea, vomiting;
  • little or no urination;
  • unusual bleeding or bruising;
  • a seizure (convulsions);
  • mouth pain or irritation, black tongue, sore throat; or
  • fever, swollen glands, rash or itching, joint pain, or feeling generally unwell.

Common side effects of dicloxacillin may include:

  • heartburn, nausea, vomiting, diarrhea;
  • blisters or ulcers in your mouth, red or swollen gums, trouble swallowing; or
  • abnormal liver function tests.

This is not a complete list of side effects, and others may occur. Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

This section was rewritten for readability and reviewed for meaning.

Dicloxacillin dosing information

Usual Adult Dose for Bronchitis:

250 to 500 mg orally every 6 hours for 10 days, depending on the nature and severity of the infection.

Usual Adult Dose for Pharyngitis:

250 mg orally every 6 hours for 10 days, depending on the nature and severity of the infection.

Usual Adult Dose for Pneumonia:

500 mg orally every 6 hours for up to 21 days, depending on the nature and severity of the infection.

Usual Adult Dose for Skin or Soft Tissue Infection:

500 mg orally every 6 hours for 7 days, or for 3 days after acute inflammation resolves, depending on the nature and severity of the infection.

Usual Adult Dose for Upper Respiratory Tract Infection:

250 mg orally every 6 hours for 7 to 21 days, depending on the nature and severity of the infection.

Usual Pediatric Dose for Skin or Soft Tissue Infection:

<40 kg: 3.125 to 6.25 mg/kg orally every 6 hours.>40 kg: 125 to 250 mg orally every 6 hours.

Usual Pediatric Dose for Upper Respiratory Tract Infection:

<40 kg: 3.125 to 6.25 mg/kg orally every 6 hours.>40 kg: 125 to 250 mg orally every 6 hours.

Usual Pediatric Dose for Osteomyelitis:

Following initial intravenous therapy:>= 1 year:<40 kg: 12.5 to 25 mg/kg orally every 6 hours, not to exceed 2000 mg/24 hours.>40 kg: 250 mg orally every 6 hours, not to exceed 2000 mg/24 hours.

Usual Pediatric Dose for Pneumonia:

<40 kg: 6.25 mg/kg orally every 6 hours.>40 kg: 250 mg orally every 6 hours.

What happens if I miss a dose?

Take the missed dose as soon as you remember. Skip the missed dose if it is nearly time for your next scheduled dose. Do not take extra medicine to make up for the missed dose.

This section was rewritten for readability and reviewed for meaning.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Antibiotic medicines can cause diarrhea, which may be a sign of a new infection. If you have diarrhea that is watery or bloody, call your doctor. Do not use anti-diarrhea medicine unless your doctor tells you to.

This section was rewritten for readability and reviewed for meaning.

What other drugs will affect dicloxacillin?

Tell your doctor about all the medicines you are currently taking and any that you begin or stop using, especially:

  • probenecid;
  • tetracycline;
  • a blood thinner (warfarin, Coumadin, Jantoven); or
  • any other antibiotic.

This list is not complete. Other drugs may interact with dicloxacillin, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide.

This section was rewritten for readability and reviewed for meaning.

Common questions about dicloxacillin

What are the best antibiotics for boils?
There is no single best antibiotic for a boil, and many boils do not need one at all. Draining the boil is the main treatment. When an antibiotic is added, the usual choices are cephalexin, dicloxacillin, trimethoprim-sulfamethoxazole (Bactrim), doxycycline, or clindamycin. Your provider picks one based on whether MRSA is likely, how sick you are, where the boil is, and your allergies. Continue reading

Related medicines

Before you take this medicine: the information on this page is general and may not cover your personal circumstances. Read the label supplied with your medicine and ask a pharmacist or doctor if you are unsure, especially if you are pregnant, breastfeeding, taking other medicines or managing a long-term condition.
General medicine information Consumer-friendly language

Content is provided for education and is not medical advice. See our medical disclaimer.