All About Erythromycin Oral Tablets

If you have a bacterial infection, your doctor may suggest treatment with erythromycin. It’s an antibiotic drug that’s used in adults and certain children to treat a wide range of infections caused by bacteria.

Examples of bacterial infections that erythromycin is used to treat include:

certain upper or lower respiratory infections
respiratory infection caused by Mycoplasma pneumonia
certain skin infections, including erythrasma
listeria infection
pertussis (whooping cough)

Before prescribing erythromycin, your doctor will likely order a test to make sure the drug is effective against the bacteria that’s causing your infection.

Erythromycin basics

Erythromycin comes as an immediate-release tablet and a delayed-release tablet. “Immediate release” means the drug is released into your body right away. “Delayed release” means the drug is released into your body after it passes through your stomach.

Erythromycin comes in other forms, including a capsule that you swallow, an eye ointment, and a topical gel. The drug also comes in other versions, such as erythromycin ethylsuccinate (EryPed, E.E.S.). But these forms are not covered in this article.

Erythromycin brand-name versions

Erythromycin delayed-release tablets are also available as the brand-name drug Ery-tab. There’s currently no brand-name version for immediate-release erythromycin tablets.

Erythromycin is a generic drug, which means it’s an exact copy of the active drug in a brand-name medication. The brand-name medication that erythromycin is based on is called Ery-tab.

Generic drugs are thought to be as safe and effective as the brand-name drug they’re based on. In general, generics usually cost less than brand-name drugs do.

If you’d like to know more about using Ery-tab instead of erythromycin, talk with your doctor. And, explore this Austra Health article to learn more about the differences between generic and brand-name drugs.

Your doctor will recommend the dosage of erythromycin that’s right for you. Below are commonly used dosages, but always take the dosage your doctor prescribes.

Forms and strengths

Erythromycin is available in the following strengths:

Immediate-release tablet: 250 milligrams (mg) and 500 mg

Delayed-release tablet: 250 mg, 333 mg, and 500 mg

Recommended dosages

The recommended dosage of erythromycin immediate-release tablets is 250 mg taken four times per day or 500 mg taken twice per day. Treatment generally lasts for at least 6 to 14 days, but in some cases, it’s longer.

Your doctor will tell you exactly how many days your erythromycin treatment will last. It’s important that you take erythromycin as directed by your doctor for the full length of time, even if you start feeling better before finishing all your doses.

The maximum recommended daily dose is 4,000 mg divided into three or four separate doses (such as 1,000 mg taken four times per day).

Delayed-release tablet dosage for adults

Erythromycin delayed-release tablets may be used in the same dosages as the immediate-release tablets described above. But this form can also be prescribed in a dose of 333 mg taken every 8 hours.

Erythromycin dosage for children

The dosage of erythromycin used in children depends on several factors. These include the child’s body weight in kilograms (kg) and the type and severity of the infection being treated. Your child’s doctor will determine the dosage that’s right for them.

The usual daily dosage of erythromycin for children is 30 to 50 milligrams per kg (mg/kg), divided into three or four doses throughout the day. The maximum dosage is 4,000 mg total per day.

For example, for a child who weighs 33.2 kg (about 73 pounds), a doctor may prescribe 250 mg of erythromycin taken four times per day (a total of 1,000 mg per day).

Children are often prescribed the liquid suspension* form of erythromycin rather than tablets, but this article doesn’t cover that form. If your child is prescribed the liquid suspension, their doctor can tell you more about the dosage.

* A liquid suspension is a type of liquid mixture.

Questions about erythromycin’s dosage

Below are some common questions about erythromycin’s dosage.

What if I miss a dose of erythromycin? If you miss a dose of erythromycin, take it as soon as you remember. But if it’s almost time for your next dose, just skip the missed dose and take the next dose as scheduled. You should not take more than one dose of erythromycin at once. Doing so could raise your risk of side effects.
Will I need to use erythromycin long term? No, erythromycin is usually taken short term to treat an infection. If you have questions about how long you’ll take erythromycin, talk with your doctor or pharmacist.
How long does erythromycin take to work? Erythromycin begins working to treat your infection after your first dose of the medication.

Find answers to some commonly asked questions about erythromycin.

Is erythromycin eye ointment used to treat pink eye?

Yes, erythromycin eye ointment may be used to treat pink eye and other bacterial infections in the eye.

This article focuses on erythromycin tablets. To learn more about erythromycin eye ointment, including its uses, talk with your doctor.

Can erythromycin oral tablets treat acne, gastroparesis, or sore throat?

Erythromycin tablets are not approved to treat acne or gastroparesis (delayed emptying of the stomach). But doctors may still prescribe the drug off-label for this use. (With off-label use, doctors prescribe a drug for a purpose other than what it’s approved for.)

Sore throat is commonly caused by infections, including some that erythromycin may be used to treat. But the drug isn’t a treatment for sore throat. It works to treat the infection that’s causing your symptoms.

To learn more about possible off-label uses of erythromycin, talk with your doctor.

How does erythromycin compare with azithromycin or clindamycin?

Erythromycin, azithromycin, and clindamycin are all antibiotics used to treat certain bacterial infections.

They’re all available as a tablet you swallow, but they also come in other forms.

These drugs also have some differences, such as causing different side effects. But they all can cause diarrhea, including severe diarrhea related to Clostridium difficile (“C. diff”) infection.

Is erythromycin a kind of penicillin?

No, erythromycin is not a kind of penicillin. Erythromycin and penicillin are both antibiotics. But erythromycin is a type of antibiotic called a macrolide.

Erythromycin may be used in people who have an allergy to penicillin. If you have a penicillin allergy, your doctor can determine whether erythromycin is right for you.

How does erythromycin work?

Erythromycin works by blocking bacteria from making proteins needed to survive. Without these proteins, the bacteria causing your infection can’t grow and will eventually die.

To learn more about how erythromycin works, talk with your doctor.

Like most drugs, erythromycin may cause mild or serious side effects. The lists below describe some of the more common side effects that erythromycin may cause. These lists don’t include all possible side effects.

Keep in mind that side effects of a drug can depend on:

your age
other health conditions you have
other medications you take

Your doctor or pharmacist can tell you more about the potential side effects of erythromycin. They can also suggest ways to help reduce side effects.

Mild side effects

Here’s a short list of some of the mild side effects that erythromycin can cause. To learn about other mild side effects, talk with your doctor or pharmacist. You can also read the prescribing information for erythromycin immediate-release tablet and erythromycin delayed-release tablet.

Mild side effects of erythromycin that have been reported include:

nausea
vomiting
belly pain
diarrhea
reduced appetite
mild allergic reaction*

Mild side effects of many drugs may go away within a few days to a couple of weeks. But if they become bothersome, talk with your doctor or pharmacist.

* To learn more about this side effect, see the “Allergic reaction” section below.

Serious side effects

Serious side effects from erythromycin can occur, but they aren’t common. If you have serious side effects from erythromycin, call your doctor right away. But if you think you’re having a medical emergency, you should call 911 or your local emergency number.

Serious side effects of erythromycin that have been reported include:

liver problems
heart rhythm problems, including long QT syndrome and arrhythmia
pancreatitis (swelling in your pancreas)
convulsions
interstitial nephritis (swelling in your kidney)
reversible hearing loss
colitis (swelling in your colon) caused by a Clostridium difficile (“C. diff”) infection
severe allergic reaction*

* To learn more about this side effect, see the “Allergic reaction” section below.

skin rash
itchiness
flushing (temporary warmth, redness, or deepening of skin color)

Erythromycin is prescribed to adults and certain children for treating a wide range of infections caused by bacteria.

Examples of bacterial infections erythromycin is used to treat include:

certain upper or lower respiratory infections
respiratory infection caused by Mycoplasma pneumonia
certain skin infections, including erythrasma
listeria infection
pertussis (whooping cough)

In addition, erythromycin may be used to prevent rheumatic fever attacks in people who are allergic to penicillin. (Rheumatic fever is a serious complication of strep throat that rarely occurs in the United States but is still common in certain other places.)

Erythromycin works by blocking bacteria from making proteins needed to survive. Without these proteins, the bacteria causing your infection can’t grow and will eventually die.

Before you take erythromycin, it’s important to discuss your overall health and any medical conditions you may have with your doctor.

Interactions

Taking a medication with certain vaccines, foods, and other things can affect how the medication works. These effects are called interactions.

Before taking erythromycin, be sure to tell your doctor about all medications you take (including prescription and over-the-counter types). Also, describe any vitamins, herbs, or supplements you use. Your doctor or pharmacist can tell you about any interactions these items may cause with erythromycin.

For information about drug-condition interactions, see the “Warnings” section below.

Interactions with drugs or supplements

Erythromycin can interact with several kinds of drugs.

Some drugs should not be taken with erythromycin due to an interaction. These drugs include:

the statin drugs simvastatin (Zocor) and lovastatin (Altoprev)
the headache drugs ergotamine (Ergomar) or dihydroergotamine (Migranal, Trudhesa)
pimozide (Orap)

Other drugs interact with erythromycin, but it may still be safe to take the drugs together (if your doctor recommends it). These include:

the heart drugs verapamil (Verelan, others), amlodipine (Norvasc), or diltiazem (Cardizem, others)
the statin drug atorvastatin (Lipitor)
the gout medication colchicine (Colcrys, Mitigare)
theophylline (Theo-24)
blood thinner drugs
sildenafil (Viagra)

This list does not contain all types of drugs that may interact with erythromycin. Your doctor or pharmacist can tell you more about these interactions and any others that may occur with use of erythromycin.

Other interactions

Erythromycin can interact with grapefruit. Eating grapefruit or drinking grapefruit juice while taking erythromycin is not recommended. Doing so can increase your risk of side effects, or it can make the side effects that you experience worse.

If you have questions about avoiding grapefruit with erythromycin, talk with your doctor or pharmacist.

Warnings

Erythromycin can sometimes cause harmful effects in people who have certain conditions. This is known as a drug-condition interaction. Other factors may also affect whether erythromycin is a good treatment option for you.

Talk with your doctor about your health history before you take erythromycin. Factors to consider include those described below.

Age 65 years and older. Adults ages 65 years and older have a higher risk of reversible hearing loss as a side effect from taking erythromycin. This risk may be even higher if you’re in this age group and have a liver or kidney problem.

Older adults also have a higher risk of irregular heart rhythm, which is a rare but serious side effect erythromycin can cause. To learn more about whether erythromycin is safe to take at your age, talk with your doctor.

Heart problems. In rare cases, erythromycin can cause heart rhythm problems, including long QT syndrome. You may have a higher risk if you already have a heart problem, especially if you have arrhythmia. If you have a heart condition, talk with your doctor about whether erythromycin is right for you.

Erythromycin and alcohol

It’s recommended that you avoid consuming alcohol while taking erythromycin. This is because alcohol may make erythromycin less effective at treating your infection.

If you have questions about drinking alcohol while taking erythromycin, talk with your doctor.

Pregnancy and breastfeeding

Erythromycin is generally considered safe to take during pregnancy after the first trimester. (The first trimester refers to the first 12 weeks of pregnancy). When used during the first trimester, there have been rare reports of heart abnormalities in newborns. But it’s not known for certain whether this is caused by erythromycin or other factors.

Erythromycin passes into breast milk in small amounts. It’s generally considered safe to breastfeed while using this drug unless your doctor advises against it. If you breastfeed while taking erythromycin, you should monitor your breastfed child for irritability, diarrhea, and diaper rash.

If you have other questions about using erythromycin while pregnant or breastfeeding, talk with your doctor.

Your doctor will explain how you should take erythromycin. They’ll also explain how much to take and how often. Be sure to follow your doctor’s instructions.

Taking erythromycin

Erythromycin comes as a tablet that you swallow.

Accessible medication containers and labels

If it’s hard for you to read the label on your prescription, tell your doctor or pharmacist. Certain pharmacies provide medication labels that:

have large print
use braille
contain a code you can scan with a smartphone to change the text to audio

Your doctor or pharmacist may be able to recommend a pharmacy that offers these options if your current pharmacy doesn’t.

Also, if you’re having trouble opening your medication bottles, let your pharmacist know. They may be able to put erythromycin in an easy-open container. Your pharmacist may also recommend tools to help make it simpler to open the drug’s container.

Questions about taking erythromycin

Below are some common questions about taking erythromycin.

Can erythromycin be chewed, crushed, or split? No, you should not crush, chew, or split erythromycin tablets. If you’re having trouble swallowing pills, check out these tips or talk with your pharmacist or doctor.
Should I take erythromycin with food? You may take erythromycin doses with or without food.
Is there a best time of day to take erythromycin? No, there’s no best time of day to take erythromycin. But you should take your erythromycin doses as directed by your doctor.

Costs of prescription drugs can vary depending on many factors. These factors include what your insurance plan covers and which pharmacy you use.

Financial assistance to help you pay for erythromycin may be available. Medicine Assistance Tool and NeedyMeds are two websites that provide resources to help reduce the cost of erythromycin.

These websites also offer tools to help you find low cost healthcare and certain educational resources. To learn more, visit their websites.

Do not take more erythromycin than your doctor prescribes. For some drugs, doing so can lead to side effects.

What to do in case you take too much erythromycin

Call your doctor if you think you’ve taken too much erythromycin. You can also call 800-222-1222 to reach America’s Poison Centers or use its online resource. But if you have severe symptoms, immediately call 911 or your local emergency number. Or go to the nearest emergency room.

If you have questions about taking erythromycin, talk with your doctor or pharmacist. Questions you may want to ask include:

Do other medications I take increase my risk of side effects from erythromycin?
If I still have symptoms of my infection after I finish taking erythromycin, what should I do?
If I have diarrhea from taking erythromycin, how should I treat it?

To get information on different conditions and tips for improving your health, subscribe to any of Austra Health’s newsletters. You may also want to check out the online communities at Bezzy. It’s a place where people with certain conditions can find support and connect with others.

Disclaimer: Austra Health has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.