Macrolides: what they treat and how to use them safely

Macrolides are a family of antibiotics you’ve probably heard of — azithromycin, clarithromycin, and erythromycin are the main ones. Doctors prescribe them for common infections like sinusitis, bronchitis, certain skin infections, and some sexually transmitted infections such as chlamydia. They’re handy because they work against many bacteria that cause respiratory and soft-tissue infections.

How macrolides work

Macrolides stop bacteria from making the proteins they need to grow. Think of it as jamming the bacteria’s protein factory. That makes the infection easier for your immune system to clear. Azithromycin and clarithromycin are taken by mouth and get into tissues well, which helps with lung and skin infections.

Common uses and safety tips

Quick examples: azithromycin is often used for community-acquired pneumonia and some sinus infections, while clarithromycin is commonly part of H. pylori treatment for stomach ulcers. Erythromycin is older and can cause more stomach upset, but it’s still used when needed.

Side effects are usually mild: nausea, diarrhea, or stomach pain. A few people can have allergic reactions. More serious issues to watch for are heart rhythm changes (QT prolongation) and interactions with other drugs. Clarithromycin and erythromycin can affect liver enzymes, so they can raise levels of some medicines. Azithromycin causes fewer drug interactions but still has risks.

Don’t use macrolides for viral infections like colds or the flu. Overuse drives resistance — bacteria can stop responding to these drugs. If your symptoms don’t improve in a few days or you feel worse, contact your clinician — you might need a different antibiotic or tests.

If you have heart disease, low potassium, or take medicines that affect heart rhythm (some antiarrhythmics, antipsychotics, or certain antidepressants), tell your doctor before starting a macrolide. Also mention blood thinners, statins, or colchicine because interactions can happen. Pregnant or breastfeeding? Many macrolides may be considered but always check with your provider first.

Practical tips: take the full course your doctor prescribes even if you feel better, stick to the dosing times, and avoid alcohol if it makes your stomach worse. If you miss a dose, take it as soon as you remember unless it’s near the next dose — don’t double up. Save leftover antibiotics for later — using leftovers can be ineffective and help resistance grow.

Resistance matters. In some places, common bacteria like Streptococcus pneumoniae are less sensitive to macrolides now. That’s why clinicians consider local resistance patterns and test results when picking an antibiotic. If you’re unsure why a macrolide was chosen, ask — a quick explanation helps you take it right.

Want help understanding a prescription or side effects? Reach out to your pharmacist or doctor. They can confirm dosing, check drug interactions, and tell you what to expect while you take the medicine.