Macrolide Antibiotics: What They Are, How They Work, and Which Ones Are Used

When your doctor prescribes an antibiotic for a stubborn sore throat, sinus infection, or bronchitis, they might reach for a macrolide antibiotic, a class of drugs that stop bacteria from making proteins they need to survive. Also known as macrolide antibiotics, these drugs are often used when someone can’t take penicillin or when other antibiotics haven’t worked. Unlike some broad-spectrum drugs, macrolides target specific bacteria without wiping out every microbe in your body—which is why they’re still a go-to for many common infections.

Three names come up most often: azithromycin, a once-daily pill often called the "Z-Pak" because of its short five-day course, erythromycin, the original macrolide, still used for skin and respiratory bugs, and clarithromycin, which works well for stomach ulcers caused by H. pylori. These aren’t just random choices—they’re selected based on the infection type, patient history, and how resistant local bacteria have become. For example, azithromycin is common for walking pneumonia, while clarithromycin pairs with other drugs to kill ulcer-causing bacteria. But resistance is growing. In some places, up to 30% of strep throat cases no longer respond to macrolides, which is why doctors don’t hand them out like candy.

Side effects are usually mild—stomach upset, nausea, or diarrhea—but they can be worse for older adults or people with liver problems. These drugs also interact with other meds, like statins or blood thinners, so it’s important to tell your doctor what else you’re taking. And while they’re not used for viruses like colds or flu, people still ask for them when they feel sick, which only makes resistance worse. That’s why knowing when macrolides actually help matters more than ever.

What you’ll find below are real patient-focused guides on how these drugs compare to others, what to watch for, and how to avoid common mistakes. From allergic reactions to cefprozil to how antibiotics like secnidazole stack up against alternatives, the posts here cut through the noise and give you clear, practical info you can use.