Erythromycin vs Alternatives: What Works Best for Bacterial Infections

If you’ve been prescribed erythromycin and are wondering if there’s a better option, you’re not alone. Many people ask: erythromycin works, but is it the best choice today? With newer antibiotics available, older drugs like erythromycin are being weighed against safer, more effective alternatives. This isn’t about ditching what’s familiar-it’s about knowing what actually works better for your body and your infection.

What erythromycin actually does

Erythromycin is a macrolide antibiotic, first introduced in the 1950s. It stops bacteria from making proteins they need to survive. It’s used for respiratory infections like bronchitis and pneumonia, skin infections like cellulitis, and some sexually transmitted infections like chlamydia. It’s also an option for people allergic to penicillin.

But here’s the catch: erythromycin has a high rate of stomach upset. About 1 in 3 people who take it get nausea, vomiting, or cramps. It also needs to be taken multiple times a day-usually 3 or 4 times-which makes compliance tough. And over time, bacteria have grown resistant to it. In the UK, resistance rates for common bugs like Streptococcus pneumoniae have climbed above 20% in some areas.

Azithromycin: the most common replacement

Azithromycin is the go-to alternative for most doctors today. It’s also a macrolide, so it works similarly to erythromycin-but with major improvements.

First, you take it once a day. For many infections, a full course is just 3 to 5 days. That’s a huge difference from erythromycin’s 7-14 days, 3-4 times daily. Second, azithromycin causes far less stomach upset. Studies show only about 1 in 10 people have digestive issues with azithromycin, compared to 1 in 3 with erythromycin.

It’s also better absorbed in the body. That means higher concentrations reach the infection site. For chlamydia, azithromycin is now the first-line treatment in the UK and US. For strep throat, it’s often preferred if penicillin isn’t an option.

But azithromycin isn’t perfect. It can rarely cause heart rhythm changes in people with existing heart conditions. And like erythromycin, resistance is growing, especially in community-acquired pneumonia.

Amoxicillin: the penicillin alternative

If you’re not allergic to penicillin, amoxicillin is often the best choice. It’s a beta-lactam antibiotic, which works differently than macrolides. Instead of blocking protein production, it attacks the bacterial cell wall.

Amoxicillin is more effective than erythromycin for many common infections. For ear infections in children, sinus infections, and strep throat, it clears bacteria faster and with fewer relapses. A 2023 UK primary care study found amoxicillin had a 92% success rate for strep throat, while erythromycin was only 78% effective.

It’s also cheaper and available as a liquid, making it ideal for kids. Side effects are mild-mostly diarrhea or rash-and serious reactions are rare.

The downside? If you’re allergic to penicillin, you can’t take it. And for some skin infections or atypical pneumonia, it doesn’t work as well as macrolides.

Doxycycline: the broad-spectrum option

Doxycycline is a tetracycline antibiotic, used for infections that erythromycin struggles with. It’s especially good for acne, Lyme disease, tick-borne illnesses, and certain types of pneumonia caused by atypical bacteria like Mycoplasma.

It’s taken once or twice a day and has a long half-life, meaning it stays active in your body longer. It’s also effective against some resistant strains that erythromycin can’t touch.

But it comes with trade-offs. You can’t take it with dairy, antacids, or iron supplements-they block absorption. It also makes your skin more sensitive to sunlight. And it’s not recommended for children under 12 or pregnant women because it can stain developing teeth.

For adults with acne or respiratory infections where macrolides are failing, doxycycline is often the next step.

Clarithromycin: the close cousin

Clarithromycin is another macrolide, very similar to erythromycin and azithromycin. It’s stronger against some bacteria and has better stomach tolerance than erythromycin. It’s often used for H. pylori infections (which cause ulcers) and lung infections in people with COPD.

Compared to erythromycin, clarithromycin is more reliable, requires fewer daily doses, and has fewer drug interactions. But it’s still not as convenient as azithromycin. It’s also more expensive and carries a slightly higher risk of liver issues.

In practice, doctors often choose clarithromycin over erythromycin-but azithromycin still wins for simplicity and tolerability.

When erythromycin might still be the right choice

Despite its flaws, erythromycin isn’t obsolete. There are a few cases where it’s still used:

• If you’re allergic to both penicillin and macrolides like azithromycin (rare, but possible).
• For certain rare infections like Legionnaires’ disease, where guidelines still list it as an option.
• If azithromycin isn’t available due to supply issues or cost.
• For infants under 1 month with chlamydia pneumonia-erythromycin is still the standard in neonatal cases.

Even then, many hospitals now use azithromycin or amoxicillin-clavulanate instead, even for newborns, because they’re safer.

What your doctor won’t always tell you

Antibiotic choice isn’t just about the bug-it’s about you. Your age, allergies, other medications, liver function, and even your last antibiotic use matter.

For example, if you’re on blood thinners, erythromycin can dangerously increase their effect. Azithromycin doesn’t. If you have liver disease, clarithromycin and erythromycin are riskier than azithromycin or amoxicillin.

And don’t assume newer = better. For simple strep throat in a healthy adult, amoxicillin still beats all macrolides in cure rates and relapse prevention.

The biggest mistake? Taking an antibiotic because it’s what you got last time. Bacteria change. Your body changes. Your infection might be different now.

How to talk to your doctor about alternatives

If you’re prescribed erythromycin and have concerns, ask these questions:

1. Is this the best option for my specific infection?
2. Are there alternatives with fewer side effects?
3. Could I take something with fewer daily doses?
4. Is there a chance this bacteria is already resistant?
5. What happens if I can’t tolerate this one?

Most doctors are open to discussing alternatives-especially if you’ve had bad reactions before. Don’t be afraid to ask. Your treatment should fit your life, not the other way around.

Bottom line: What to choose

Here’s a quick guide based on common infections:

There’s no single ‘best’ antibiotic. But erythromycin is rarely the top pick anymore. Azithromycin, amoxicillin, and doxycycline have mostly taken over because they’re easier to take, better tolerated, and more effective.

If you’re on erythromycin and feeling sick from it, talk to your doctor. There’s likely a better option waiting.

Next steps if you’re on erythromycin

• Don’t stop taking it unless your doctor says so-even if you feel better.
• Write down any side effects you experience: nausea, dizziness, rash, or diarrhea.
• Call your doctor if symptoms don’t improve in 2-3 days.
• Ask: "Is there a simpler, better-tolerated option for my infection?"

Antibiotics save lives-but they’re not one-size-fits-all. The right one depends on your infection, your body, and your history. Erythromycin has its place, but for most people today, better choices exist.