Amoxicillin Dosage: What You Need to Know for Safe and Effective Use

When you’re prescribed amoxicillin, a widely used penicillin-type antibiotic that treats bacterial infections like ear infections, pneumonia, and strep throat. Also known as Amoxil, it’s one of the most common antibiotics doctors reach for because it’s effective, affordable, and generally well-tolerated. But getting the amoxicillin dosage right matters just as much as taking it at all. Too little won’t kill the infection. Too much can cause side effects or even lead to antibiotic resistance.

For adults, the standard dose for most infections is 500 mg every 8 hours or 875 mg every 12 hours. But if you’re treating something like a sinus infection or urinary tract infection, your doctor might start lower—like 250 mg three times a day. For kids, it’s all about weight: usually 20 to 50 mg per kilogram of body weight per day, split into two or three doses. A 30-pound child might get 125 mg every 8 hours, while a 70-pound child could need 250 mg. That’s why you never guess a child’s dose—you follow the label or your provider’s instructions exactly.

It’s not just about how much you take, but when and how long. Amoxicillin works best when kept at a steady level in your blood, so spacing doses evenly—every 8 or 12 hours—is key. Skipping doses or stopping early because you feel better is one of the biggest mistakes people make. That’s how resistant bacteria survive and spread. Most courses last 7 to 10 days, even if symptoms vanish after day three. And if you’re allergic to penicillin, amoxicillin is off-limits. A rash, swelling, or trouble breathing? Get help right away.

Amoxicillin doesn’t work on viruses, so it won’t help with colds, flu, or most sore throats. But when it’s the right fit—for strep, ear infections, Lyme disease, or dental infections—it can make a real difference. It’s often paired with clavulanic acid (like in Augmentin) when bacteria are harder to kill. And while side effects like diarrhea or nausea are common, they’re usually mild. Taking it with food can help if your stomach gets upset.

What you’ll find below are real, practical guides from people who’ve used amoxicillin—whether for a child’s ear infection, a stubborn sinus issue, or a post-surgery infection. You’ll see how dosage changes based on age, weight, and infection type. You’ll learn what to watch for, how to avoid common errors, and how it compares to other antibiotics like cephalexin or azithromycin. No fluff. Just what works.