Alternatives to Dicloxacillin If You Can't Fill Your Prescription

Dicloxacillin is prescribed for a specific reason — it's one of the few oral antibiotics that's resistant to beta-lactamase enzymes produced by certain staph bacteria. But if you can't find it at any pharmacy near you, several alternatives may work just as well. Here's what you need to know before talking to your doctor.

Important: Always Talk to Your Doctor Before Switching

Dicloxacillin may have been chosen for a specific reason — a culture result, your allergy history, or the type and severity of your infection. Do not switch antibiotics without consulting your prescriber. The goal of this guide is to help you have an informed conversation, not to substitute for medical advice.

What Dicloxacillin Is Used For

Dicloxacillin is a penicillinase-resistant penicillin. It's specifically designed to fight methicillin-susceptible Staphylococcus aureus (MSSA) — the type of staph that is NOT drug-resistant (MRSA). Common conditions it treats include:

Cellulitis and skin infections

Impetigo

Folliculitis, boils, and carbuncles

Mastitis

Bone infections (osteomyelitis) caused by susceptible bacteria

Alternative #1: Cephalexin (Keflex)

Cephalexin is the most commonly recommended alternative to Dicloxacillin and is considered clinically equivalent for most staph skin infections. It's a first-generation cephalosporin antibiotic with a nearly identical spectrum of activity against MSSA.

Key advantages over Dicloxacillin:

More convenient dosing (twice daily vs. four times daily)

Can be taken with or without food — no fasting required

Available at virtually every pharmacy

Available in liquid form for children

Note: Cephalexin should be used with caution in patients with a severe penicillin allergy due to potential cross-reactivity, though this is uncommon.

Alternative #2: Clindamycin

Clindamycin is a lincosamide antibiotic effective against both MSSA and many strains of MRSA, making it a good choice when drug-resistant staph is a concern. It's particularly useful for patients with penicillin or cephalosporin allergies.

Key considerations: Clindamycin can cause antibiotic-associated colitis (C. diff) more commonly than some alternatives. Local resistance patterns matter — your doctor or lab can check sensitivity. Typically dosed three times daily.

Alternative #3: TMP-SMX (Trimethoprim-Sulfamethoxazole / Bactrim)

TMP-SMX, sold as Bactrim or Septra, is a combination antibiotic that covers MRSA as well as MSSA. It's often preferred in high-MRSA areas or for purulent (pus-producing) skin infections where MRSA cannot be ruled out. It is widely available, inexpensive, and comes in generic form.

Key considerations: Not ideal for streptococcal infections. Sulfa allergies are relatively common, so check your allergy history before taking. Taken twice daily with adequate water.

Alternative #4: Amoxicillin-Clavulanate (Augmentin)

Augmentin combines amoxicillin with clavulanate, a beta-lactamase inhibitor. This combination can treat MSSA skin infections and is also useful for mixed infections (e.g., animal bites) that may involve additional bacteria types. It's more broadly available than Dicloxacillin.

Key considerations: Broader spectrum means more impact on gut flora. GI side effects (diarrhea, nausea) are common. Not appropriate if MRSA coverage is needed.

Alternatives That Do NOT Work for Staph Infections

It's equally important to know what won't work. The following antibiotics are NOT effective against MSSA and should not be used as substitutes for Dicloxacillin without culture confirmation:

Amoxicillin alone (without clavulanate) — broken down by staph's penicillinase enzyme

Penicillin G or V — similarly vulnerable to beta-lactamases

Azithromycin (Z-pack) — not reliably active against staphylococci

How to Talk to Your Doctor About Switching

Call your prescriber's office and explain that Dicloxacillin is unavailable in your area. Most providers have a prepared list of equivalent alternatives and can quickly send a new prescription to a pharmacy that has the substitute in stock. This is a routine request — don't hesitate to ask.

If you'd rather stick with Dicloxacillin, medfinder can search local pharmacies on your behalf to find which ones have it in stock. Learn more about why Dicloxacillin is hard to find and what you can do.