Cefaclor vs Amoxicillin: Which Antibiotic Is Right for You?

When your doctor prescribes an antibiotic for a bacterial infection, you might hear Cefaclor, a second-generation cephalosporin antibiotic used for respiratory, ear, and urinary tract infections or amoxicillin, a penicillin-class antibiotic commonly used for sinus, throat, and lung infections. Both fight bacteria, but they’re not interchangeable. Choosing between them isn’t about which is "stronger"—it’s about which matches your infection, allergies, and body’s response.

Amoxicillin is one of the most prescribed antibiotics worldwide because it’s broad-spectrum, affordable, and effective against many common bugs like strep throat and ear infections. But if you’re allergic to penicillin, amoxicillin is off the table—full stop. That’s where Cefaclor, a cephalosporin antibiotic that works similarly to penicillins but often tolerated by people with mild penicillin allergies comes in. It’s not a perfect substitute, though. Some people allergic to penicillin can still react to Cefaclor, so your doctor will check your history carefully. Side effects differ too: amoxicillin often causes stomach upset or diarrhea, while Cefaclor can trigger rashes or yeast infections more often, especially in women.

Neither drug works against viruses, so if you have a cold or flu, neither will help. But if you have a bacterial sinus infection, bronchitis, or a stubborn ear infection, your doctor picks based on past effectiveness, local resistance patterns, and your personal health. For example, if you’ve taken amoxicillin before and it didn’t work, Cefaclor might be the next step. Or if you’re on birth control, amoxicillin can reduce its effectiveness—Cefaclor doesn’t have that issue. Even cost matters: amoxicillin is usually cheaper, especially as a generic, while Cefaclor might cost more depending on your pharmacy and insurance.

You’ll also find that some infections respond better to one than the other. Cefaclor is often chosen for skin infections or when a broader coverage is needed, while amoxicillin is the go-to for simple strep throat or early pneumonia. Both are taken orally, usually two to three times a day, but dosing changes based on age, weight, and kidney function. Kids get liquid forms, adults get pills. Neither should be stopped early—even if you feel better—because that’s how resistant bacteria start.

What you won’t find in this collection are vague generalizations or marketing fluff. Instead, you’ll see real comparisons drawn from clinical experience: how patients reacted, what side effects showed up, which infections cleared faster, and when switching from one to the other made a difference. You’ll also find posts about managing antibiotic side effects, avoiding drug interactions, and recognizing when you need something stronger than either Cefaclor or amoxicillin—like Bactrim or Roxithromycin, which show up in other guides here. This isn’t about picking a winner. It’s about understanding your options so you can ask the right questions and get the right treatment.