Specifically, the Food and Drug Administration (FDA) has approved clarithromycin oral tablet to treat:

chronic bronchitis flare-ups in adults
sinus infections in adults and children 6 months and older
community-acquired pneumonia in adults and children 6 months and older
pharyngitis in adults and children 6 months and older
tonsillitis in adults and children 6 months and older
skin infections in adults and children 6 months and older
ear infections in children 6 months and older
mycobacterial infections in adults and children 20 months and older
Helicobacter pylori (H. pylori) infections in adults
duodenal ulcer disease in adults

This article describes possible side effects of clarithromycin oral tablet. You can explore this overview article to learn more about clarithromycin, including the drug’s uses, side effects, ways to save on cost, and more.

Clarithromycin oral tablet is a generic medication. It isn’t available in a brand-name version. Clarithromycin also comes in an extended-release* oral tablet and oral suspension, but these forms aren’t described in this article. To learn more about these forms, talk with your doctor.

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* “Extended release” means the drug is slowly released into your body over a long period of time.

More common side effects of clarithromycin

Clarithromycin oral tablet may cause mild or serious side effects. Below are some of the more common side effects of clarithromycin oral tablet that occurred during the drug’s studies. The more common side effects varied based on the condition being treated.

More common side effects reported in people taking clarithromycin oral tablet for mycobacterial infections include:

nausea
diarrhea
changes in taste
abdominal pain
vomiting

More common side effects reported in people taking clarithromycin oral tablet for duodenal ulcers caused by H. pylori infections include:

changes in taste
nausea
headache
diarrhea
vomiting

Mild side effects of clarithromycin

Clarithromycin may cause certain mild side effects. Most often, mild side effects are temporary and can be easily managed. Tell your doctor or pharmacist if you have side effects that don’t go away or become bothersome.

Mild side effects of clarithromycin oral tablet that occurred in studies include:

diarrhea
changes in taste
nausea
vomiting
abdominal pain
headache
indigestion
gas
rash
infection
vertigo (spinning sensation)
hearing problems
dry mouth
tiredness
loss of appetite
muscle aches or spasms
tremor (shakiness)
sleepiness
nervousness
mild allergic reaction*

* To learn more about this side effect, see the “Side effects of clarithromycin in detail” section below.

Clarithromycin oral tablet may cause more mild side effects than those listed above. For details, see the drug’s prescribing information.

Serious side effects of clarithromycin

Clarithromycin may cause certain serious side effects. If you have any serious side effects from clarithromycin oral tablet, call your doctor right away. But if you think you’re having a medical emergency or your side effects feel life threatening, take immediate action. Call 911 or a local emergency number, or go to the nearest emergency room.

After the FDA approves a drug, it tracks and reviews side effects of the medication. Visit MedWatch’s website if you’d like to notify the FDA about a side effect you’ve had with clarithromycin.

Serious side effects of clarithromycin oral tablet that occurred in studies include:

liver problems*
QT prolongation*
Clostridium difficile (C. diff) associated diarrhea (CDAD)*
atypical blood cell levels
arrhythmia (irregular heart rate)
cardiac arrest
severe allergic reaction*

* To learn more about this side effect, see the “Side effects of clarithromycin in detail” section below.

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Common questions about side effects of clarithromycin

Here are answers to some common questions about side effects of clarithromycin oral tablet. If you have other questions, talk with your doctor or pharmacist.

How long do side effects of clarithromycin usually last?

It depends on the side effect. Most often, mild side effects of clarithromycin are temporary and will go away as your body gets used to the medication or after treatment is complete. However, certain side effects may last longer, such as CDAD* and liver problems*.

If you have more questions about this, talk with your doctor.

* To learn more about this side effect, see the “Side effects of clarithromycin in detail” section below.

Does clarithromycin cause long-term side effects?

Yes, in some cases clarithromycin oral tablet may cause long-term side effects. These can last for a while after you’ve stopped taking the drug.

Examples of long-term side effects reported with clarithromycin oral tablet include:

CDAD*
liver problems*

Talk with your doctor to learn more about these side effects and how to manage them. Ask your doctor for more information about how long these side effects of clarithromycin may last.

* To learn more about this side effect, see the “Side effects of clarithromycin in detail” section below.

Can clarithromycin be used for whooping cough? If so, are the side effects similar as when it’s used for other infections?

Maybe. But clarithromycin isn’t approved to treat whooping cough.

In some cases, doctors may prescribe clarithromycin off-label for whooping cough. With off-label use, doctors prescribe a drug for a purpose other than what it’s approved for.

If you have questions about treatment options for whooping cough, talk with your doctor.

Side effects of clarithromycin in detail

Below you’ll find details on some of the side effects of clarithromycin oral tablet.

QT prolongation

In studies, QT prolongation was rare in people taking clarithromycin oral tablet. This side effect may be serious.

QT prolongation is a heart rhythm problem. With this side effect, your heart takes longer than usual to contract and relax. QT prolongation can increase the risk of atypical heart rhythms and sudden cardiac arrest.

With QT prolongation, you may not experience symptoms. A doctor typically diagnoses QT prolongation through an ECG. If symptoms do occur, you may feel heart palpitations, dizziness, fainting, or seizures.

Certain factors can increase the risk of QT prolongation with clarithromycin oral tablet. These include:

being ages 65 years and older
being female
having a history of diabetes, heart disease, or thyroid disorders

Ways to manage

Due to this risk, doctors typically won’t prescribe clarithromycin if you have known heart rhythm problems, are taking other drugs that can affect your heart rhythm, have low blood potassium or magnesium levels, have a significantly slow heart rate, or if you take certain antiarrhythmic drugs.

If you have concerns about QT prolongation, tell your doctor. They can help determine your risk of QT prolongation and discuss alternative treatments for your infection.

Clostridium difficile (C. diff) associated diarrhea (CDAD)

Like other antibiotics, clarithromycin can cause CDAD. Antibiotics change the usual bacteria in the colon. This can lead to an overgrowth of certain bacteria such as C. diff.

In addition to diarrhea, symptoms of CDAD include watery and bloody stools, stomach cramps, and fever. These symptoms can occur during and even 2 months after finishing treatment with clarithromycin.

Ways to manage

If you experience symptoms of CDAD, tell your doctor. They can discuss treatment options with you and they can help determine whether you should stop taking clarithromycin.

Liver problems

In studies, liver problems were rare in people taking clarithromycin oral tablet. This side effect may be serious.

Clarithromycin can cause serious liver problems, including hepatitis and liver failure. Symptoms of liver problems may include:

loss of appetite
yellowing of the skin or eyes
dark urine
itchiness
tender abdomen

Ways to manage

If you experience symptoms of liver problems, talk with your doctor right away. They’ll likely have you stop taking the medication. They can also discuss alternative medications for your condition.

Allergic reaction

For some people, clarithromycin oral tablet can cause an allergic reaction.

Symptoms can be mild or serious, and they may include:

itchiness
skin rash
swelling under the skin, typically affecting eyelids, lips, hands, or feet
swelling of the mouth, tongue, or throat, which can make it hard to breathe
flushing (temporary warmth, redness, or deepening of skin color)

Ways to manage

For mild allergic reaction symptoms, such as a mild rash, call your doctor right away. They may recommend treatments to help manage your symptoms. They’ll also let you know whether you should keep taking the medication.

For severe allergic reaction symptoms, such as swelling or trouble breathing, call 911 or your local emergency number right away. These symptoms require immediate medical care because they can become life threatening.

If you’ve had a serious allergic reaction to clarithromycin oral tablet, your doctor may recommend taking a different medication instead.

Warnings for clarithromycin

Below are some factors you may want to discuss with your doctor before taking clarithromycin oral tablet.

Warnings

It may not be safe for you to take clarithromycin oral tablet if you have specific health conditions. These are sometimes called drug-condition interactions. Other things may also affect whether clarithromycin oral tablet is a safe treatment option for you.

Before taking clarithromycin oral tablet, tell your doctor about your health and medications you take. Things to consider include:

liver disease
myasthenia gravis
heart-related medical conditions
if you’re currently pregnant or breastfeeding
all prescription and over-the-counter medications, vitamins, and supplements you take
past allergic reaction to clarithromycin

Clarithromycin and pregnancy

Clarithromycin oral tablet should not be taken during pregnancy. If you’re planning a pregnancy or can become pregnant, talk with your doctor before taking this medication. Your doctor may suggest birth control options to use during treatment with clarithromycin.

Clarithromycin and breastfeeding

It’s not known whether clarithromycin oral tablet should be taken while breastfeeding. If you’re currently breastfeeding or planning to do so, talk with your doctor before taking this medication.

Clarithromycin and alcohol

Clarithromycin oral tablet isn’t known to interact with alcohol.

But your doctor may still recommend that you avoid alcohol while taking clarithromycin. Combining alcohol and antibiotics can increase the risk of side effects and make it harder for your body to heal from an infection.

If you drink alcohol, talk with your doctor about whether it’s safe to consume it during your treatment with clarithromycin oral tablet.

What to ask your doctor

This article describes common and serious side effects of clarithromycin oral tablet. If your doctor prescribes this medication, they can discuss possible side effects with you. Let your doctor know if you have concerns or questions about treatment with this medication.

Here’s a list of some possible questions you may want to ask your doctor:

Am I at greater risk of QT prolongation because of my medical history?
Is the risk of liver problems greatest when I first start treatment?
Will my usual sense of taste return after I finish treatment?

Disclaimer: Optum Perks 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.