Azithromycin Dosage: Quick Guide for Adults & Kids

Azithromycin (brand name Zithromax) is a common antibiotic that treats ear infections, strep throat, bronchitis, and a few sexually transmitted infections. Getting the dose right matters – too little may not clear the bug, too much can cause stomach upset or heart issues. Below you’ll find the most used dosing schedules, how to adjust for weight, and what to do if you skip a pill.

Standard adult dosing

For most infections, doctors prescribe a 5‑day “Z‑pack.” The first day you take 500 mg (two 250 mg tablets) once, then 250 mg once daily for the next four days. This short course works for throat infections, sinusitis, and uncomplicated pneumonia.

If you’re treating a sexually transmitted infection like chlamydia, the plan is often a single 1 g dose (four 250 mg tablets) taken at once. For certain skin infections, the dose may be 500 mg once daily for three days.

People with liver disease or who are taking certain heart‑meds (like amiodarone) might need a lower dose, so always tell your doctor about other meds.

Kids, weight‑based dosing & special situations

Children get azithromycin based on weight, usually 10 mg per kilogram on day 1, then 5 mg/kg once daily for the next four days. For example, a 30‑kg child would take 300 mg (about one 250 mg tablet plus a half) on day 1, then 150 mg daily thereafter.

For infants under 6 months or kids who can’t swallow tablets, the medicine comes as a liquid (suspension). The same mg/kg rule applies, and a dosing syringe makes it easy to measure the exact amount.

If you miss a dose, take it as soon as you remember unless it’s almost time for the next one. In that case, skip the missed pill – don’t double up. Skipping a dose doesn’t usually ruin the whole treatment, but try to stay as close to the schedule as possible.

When you finish the course, you might still feel a little sore or have a mild cough. That’s normal; the antibiotic has already killed most of the bacteria. If symptoms get worse after a few days, call your doctor – you may need a different drug.

Remember to store tablets at room temperature, away from moisture, and keep the liquid suspension refrigerated after opening. Never share your pills with anyone else, even if they have the same infection.

With the right dose and timing, azithromycin clears infections fast and lets you get back to daily life. If you’re ever unsure about the numbers on the label, ask your pharmacist – they love a quick dosage question.