Dicloxacillin

Dicloxacillin is a penicillinase-resistant penicillin antibiotic that kills bacteria by inhibiting PBP (Penicillin-binding proteins) — enzymes essential for bacterial cell wall synthesis. Without a functional cell wall, bacteria lyse and die.

Its structural resistance to the penicillinase (beta-lactamase) enzyme makes it highly effective against MSSA (Methicillin-susceptible Staphylococcus aureus). It does not cover MRSA or Gram-negative bacteria.

Dicloxacillin treats infections caused by susceptible Staphylococcus aureus and Streptococcus pyogenes, with a primary focus on skin and soft-tissue infections.

• Impetigo — Blistering and crusting skin infection
• Cellulitis — Skin and subcutaneous tissue infection
• Folliculitis and Furuncle — Infected hair follicles and small abscesses
• Carbuncle — Large multi-follicle abscess
• Infected wounds — Traumatic or post-surgical wounds with Staph contamination
• Hordeolum (stye) — Eyelid Staph infection, used alongside topical eye drops

Dicloxacillin is not appropriate for respiratory, urinary, or bloodstream infections without medical diagnosis.

Dicloxacillin must be taken 30-60 minutes before food or 2 hours after eating. Food reduces drug absorption by 30-50%, leaving blood levels too low to treat the infection.

• Adults (mild-moderate): 250-500 mg every 6 hours (4 times daily) for 7-10 days
• Adults (severe infection): 500 mg every 4-6 hours as directed by your doctor
• Children under 40 kg: 12.5-25 mg/kg/day divided every 6 hours (consult a pharmacist)

Complete the full course even if you feel better. Stopping early causes antibiotic resistance. Take with plenty of water and store in a cool, dry place.

Dicloxacillin is generally well tolerated, but side effects can occur.

• Common (1-10%): Nausea, vomiting, abdominal pain, diarrhoea — usually mild
• Uncommon (less than 1%): Rash, urticaria, headache
• Stop and seek immediate attention for: Stevens-Johnson syndrome, difficulty breathing, facial or throat swelling (Anaphylaxis), bloody diarrhoea
• Hepatotoxicity (rare): Jaundice, dark urine — discontinue and see a doctor

To reduce gastrointestinal side effects, take a probiotic at least 2 hours apart from the antibiotic.

Both are penicillin-class antibiotics but target very different infections.

• Dicloxacillin — Penicillinase-resistant, for Staphylococcal skin infections (abscesses, cellulitis, impetigo, folliculitis)
• Amoxicillin from our Amoxicillin collection — Broader spectrum, for respiratory infections such as tonsillitis and otitis media

These antibiotics are not interchangeable. Choosing the wrong one promotes antibiotic resistance. Consult a pharmacist to match the antibiotic to your specific infection.

Antibiotic resistance is a global crisis. MRSA — resistant to Dicloxacillin — is now widespread in hospitals and the community.

To help prevent resistance:

• Always complete the full course — Stronger bacteria survive and multiply if you stop early
• Never share antibiotics — Different infections need different antibiotics
• Do not self-prescribe — Consult a pharmacist or doctor first
• Do not use leftover antibiotics — Insufficient stock won't complete a new course

Browse other antibiotics in our Antibiotic collection.

Dicloxacillin has the following contraindications and precautions:

• Penicillin allergy — Absolute contraindication; risk of life-threatening Anaphylaxis
• Cephalosporin allergy — Cross-reactivity in approximately 1-10%; inform your pharmacist
• Severe liver disease — May accumulate; dose adjustment required under medical supervision
• Pregnancy and breastfeeding — FDA Category B; consult a doctor before use
• Neonates — Consult a paediatrician only

Disclose all current medications before starting — Dicloxacillin may interact with Warfarin and Methotrexate.