Cefazolin Drug Interactions: What You Need to Know

If you're being treated with Cefazolin, it's important to know which medications and substances can interact with it. While Cefazolin has fewer drug interactions than many other antibiotics, there are still some important ones to be aware of.

This guide covers the major and moderate interactions, supplements and OTC medications to watch for, and what information your doctor needs to keep you safe.

How Drug Interactions Work

Drug interactions happen when one medication affects how another medication works in your body. This can mean:

• One drug increases or decreases the blood levels of another
• Two drugs together increase the risk of side effects
• One drug reduces the effectiveness of another

Because Cefazolin is given by injection and processed through the kidneys, most of its interactions involve drugs that affect kidney function or blood clotting. For a complete overview of Cefazolin, see What Is Cefazolin?

Major Drug Interactions

These interactions are clinically significant and require careful monitoring or possible dose adjustments:

Probenecid

Probenecid (used to treat gout) slows down how quickly your kidneys remove Cefazolin from your body. This causes Cefazolin blood levels to rise higher than normal, which can increase the risk of side effects. If you take Probenecid, your doctor may need to lower your Cefazolin dose.

Warfarin and Other Blood Thinners

Cefazolin may enhance the blood-thinning effects of Warfarin (Coumadin) and similar anticoagulants. This can increase your risk of bleeding. If you take a blood thinner, your doctor will likely monitor your INR (a blood clotting test) more frequently during Cefazolin treatment.

Aminoglycoside Antibiotics

When Cefazolin is used alongside aminoglycoside antibiotics like Gentamicin or Tobramycin, there's an increased risk of kidney damage (nephrotoxicity). Doctors sometimes use these drugs together intentionally for serious infections, but they'll closely monitor your kidney function.

Moderate Drug Interactions

Live Vaccines

Antibiotics like Cefazolin may reduce the effectiveness of live vaccines, including BCG and oral typhoid vaccine. If you're scheduled for a live vaccine, let your doctor know you're on Cefazolin. You may need to postpone the vaccine until after your antibiotic course is complete.

Loop Diuretics

Loop diuretics like Furosemide (Lasix) may increase the risk of kidney damage when used with Cefazolin. If you're on a diuretic, your doctor will monitor your kidney function during treatment.

Supplements and OTC Medications

Cefazolin has relatively few interactions with over-the-counter products and supplements. However, there are still a few things to keep in mind:

• Probiotics — Actually beneficial! Taking probiotics during and after antibiotic treatment may help prevent diarrhea and yeast infections. Ask your doctor about timing — take probiotics a few hours apart from your Cefazolin dose for best results.
• Iron supplements — No direct interaction with Cefazolin, but if you're taking iron for anemia, make sure your doctor knows.
• Antacids — Since Cefazolin is given by injection (not orally), antacids won't affect its absorption. No interaction here.
• OTC pain relievers — Acetaminophen (Tylenol) is generally safe. NSAIDs like Ibuprofen (Advil) should be used with caution if you're at risk for kidney issues, since Cefazolin is cleared by the kidneys.

Food and Drink Interactions

Because Cefazolin is administered by injection rather than taken by mouth, there are no significant food interactions. You don't need to avoid any specific foods while receiving Cefazolin.

That said, alcohol deserves a mention. While Cefazolin does not cause the severe "disulfiram-like" reaction that some other cephalosporins (like Cefotetan) can cause, it's still generally wise to avoid alcohol while fighting an infection. Alcohol can weaken your immune system and may worsen side effects like nausea and diarrhea.

What to Tell Your Doctor

Before starting Cefazolin, make sure your doctor and pharmacist know about:

• All prescription medications you're currently taking — especially blood thinners, gout medications, diuretics, and other antibiotics
• Over-the-counter medications — including pain relievers and allergy medications
• Vitamins and supplements
• Any allergies — especially to penicillin, cephalosporins, or other antibiotics
• Kidney problems — Cefazolin dosing must be adjusted for kidney disease
• Upcoming vaccinations — especially live vaccines

Being upfront about everything you're taking is the best way to avoid interactions and stay safe during treatment.

For more on potential side effects to watch for, see our guide on Cefazolin side effects.

Final Thoughts

Cefazolin is generally a well-tolerated antibiotic with a manageable interaction profile. The most important interactions to know about involve Probenecid, Warfarin, and aminoglycoside antibiotics. Beyond those, there are few surprises.

The best thing you can do is give your healthcare team a complete picture of everything you're taking. That way, they can adjust doses and monitoring to keep you safe.

If you need help finding Cefazolin, Medfinder can help you locate it in stock near you. For information on the current supply situation, read our Cefazolin shortage update.