What is Biaxin (Clarithromycin)?

Biaxin, also known as clarithromycin, is a prescription antibiotic medication used to treat various bacterial infections. It belongs to the macrolide class of antibiotics. It works by inhibiting the growth of bacteria, thereby helping to eliminate the infection. Biaxin is commonly prescribed for respiratory tract infections, such as pneumonia and bronchitis, as well as skin and soft tissue infections. It is available in tablet form, typically taken orally twice daily. It is important to complete the full course of treatment as prescribed by a healthcare professional, even if symptoms improve. Common side effects may include nausea, diarrhea, and stomach pain. It is important to inform a healthcare provider about any existing medical conditions or medications before starting treatment.


Prescription Required.

Product of Canada.

Shipped from Canada.

Prescription Required.Product of Canada.Shipped from Canada.

What is Biaxin (Clarithromycin)?

The generic name for Biaxin is Clarithromycin, an antibiotic that is chemically linked to erythromycin and azithromycin (Zithromax). It is a semi-synthetic drug used to fight infections resulting from bacteria. The types of bacteria it works on include:

  • Haemophilus influenzae
  • Streptococcus pneumoniae
  • Mycoplasma pneumoniae
  • Staphylococcus aureus
  • Mycobacterium avium

It falls into the category of medications named macrolide antibiotics. It is available as an oral tablet, in an immediate-release form, in an extended-release form, and as an oral suspension. Clarithromycin was approved by the FDA in October 1991. Not all forms of Biaxin can be used for the conditions mentioned here.

How does it work?

Biaxin works by killing or at least stopping bacteria from spreading and causing certain infections. These include:

  • bacterial throat infections
  • sinus infections
  • ear infections
  • bronchitis
  • pneumonia
  • skin infections, such as:
    • impetigo
    • cellulitis

Biaxin is also used to prevent and treat infections such as mycobacterium avium complex (MAC), infections that are related to human immunodeficiency virus (HIV) infection. Additionally, H. pylori, a bacteria that can result in ulcers in the digestive tract, can be treated with Biaxin in combination with other medicines.

Appearance & Ingredients

Biaxin is available in 250 mg and 500 mg tablets.

250 mg

The 250 mg tablets are bright yellow, oval-shaped, biconvex, and film-coated, engraved with “CLA250” on one side while the other side is plain. They contain 250 mg of clarithromycin while the nonmedicinal ingredients include:

  • crospovidone
  • magnesium stearate
  • stearic acid
  • colloidal silicon dioxide
  • hydroxyethyl cellulose
  • polyethylene glycol
  • titanium dioxide
  • D&C Yellow No. 10, and sunset yellow.

500 mg

The 500 mg tablets are a lighter shade of yellow, capsule-shaped, biconvex, and film-coated, engraved with “CLA500” on one side while the other is plain. They contain 500 mg of clarithromycin while the nonmedicinal ingredients include:

  • crospovidone
  • magnesium stearate
  • stearic acid
  • colloidal silicon dioxide
  • hydroxyethyl cellulose
  • polyethylene glycol
  • titanium dioxide
  • D&C Yellow No. 10


For adults, the recommended dose is either 250 mg or 500 mg of Biaxin twice a day, every 12 hours. The length of treatment will depend upon the condition and be for 7 to 14 days.

Taken in its extended-release form, the recommended dose of Biaxin is 1,000 mg made up of two tablets that are taken once a day for 5 to 14 days. Again, the length of the treatment will depend upon the condition.

When treating MAC, the normal recommended dose is 500 mg taken twice a day.

When combined with other medicines to kill H. pylori, the normal recommended dose is 500mg twice a day for 10 days.

For children, the recommended dose is 15 mg per kilogram of body weight daily. The maximum daily dose should not exceed 1,000 mg. The total daily dose should be given in two equal doses, 12 hours apart. The typical length of treatment is 5 to 10 days, but this will depend upon the condition.

For the prevention and treatment of MAC, the typical dose of Biaxin is 7.5 mg for every kilogram of body weight, up to a maximum of 500 mg, taken twice daily.

An oral syringe should be used to measure the dose if the oral suspension of Biaxin is being taken by the child. An oral syringe is better than a regular household spoon as it gives a much more accurate measurement.

Biaxin can be taken with or without food, but taking it with food means it is less likely to cause an upset stomach. However, it is essential that Biaxin in its extended-release form is taken with food. These tablets must be swallowed, not broken or crushed.

Side Effects

Not everyone who uses Biaxin will experience the side effects listed below. If you are concerned about the possible side effects, you should discuss them, along with the benefits of Biaxin with your doctor before you take it.

At least 1% of the patients taking Biaxin have reported the following side effects. In many cases, these can be managed, or may naturally dissipate over time. Your pharmacist may be able to provide guidance for managing the side effects of Biaxin, but you should speak with your doctor if they are severe or become a nuisance.

  • abdominal pain
  • change in sense of taste
  • confusion
  • diarrhea (mild)
  • disorientation
  • dizziness
  • gas
  • headache
  • hearing trouble
  • heartburn
  • nausea
  • ringing in the ears
  • vomiting

While the following side effects don’t often occur, they can cause significant issues if you do not follow up with your doctor or medical professional.

  • severe abdominal or stomach cramps and pain
  • skin rash
  • symptoms of liver problems, such as:
    • abdominal tenderness
    • yellow eyes or skin
    • skin rash
    • itching
    • dark urine
  • symptoms of myasthenia gravis, such as:
    • muscle weakness
    • drooping eyelid
    • vision changes
    • trouble chewing and swallowing
    • difficulty breathing
  • watery, bloody, and severe diarrhea

If any of the following appear, immediately stop using Biaxin and find medical help.

  • abnormal or irregular heartbeat
  • symptoms of a severe allergic reaction, such as:
    • hives
    • difficulty breathing; sore throat
    • swollen face, mouth, throat, or tongue
  • symptoms of a severe skin reaction, such as:
    • peeling or blistering skin

Other side effects may occur, you should see your doctor if you develop any symptoms that worry you whilst on Biaxin.

Warnings & Precautions

Before starting treatment with Biaxin, let your doctor know of any allergies or medical issues you have. Make sure they are aware of all the other medications you are taking. Let them know if you are pregnant, or breastfeeding, or if there are any other health-related issues your doctor needs to know about, as these may have an impact on how you should take Biaxin.

You should not take Biaxin if you:

  • are allergic to Biaxin or any of its ingredients
  • are allergic to any other macrolide antibiotics
  • have had jaundice or liver problems linked to clarithromycin
  • have severe liver failure in addition to decreased kidney function
  • have or have had QT prolongation or an irregular heartbeat
  • have untreated low potassium levels in the blood
  • are taking any of the following medicines:
    • astemizole
    • cisapride
    • colchicine
    • domperidone
    • ergot alkaloids, such as
      • dihydroergotamine
      • ergonovine
      • ergotamine
      • Methylergonovine
    • oral midazolam
    • pimozide
    • saquinavir
    • “statin” cholesterol-lowering medicines, such as:
      • lovastatin
      • simvastatin
    • terfenadine
    • ticagrelor

Irregular heartbeat

QT prolongation is a type of heart rhythm problem that may be caused by Biaxin. You should discuss it with your doctor before taking Biaxin if you have had QT prolongation in the past, or a medical condition linked to it. This may affect whether you can take Biaxin, your dosage, how effective it may be or whether you may need any additional monitoring.


An allergic reaction to Biaxin is more likely if you are already allergic to erythromycin or azithromycin. You should contact your doctor if you develop allergy symptoms such as a rash after taking Biaxin. Immediately seek medical attention if you experience any of the following after taking Biaxin.

  • Hives
  • Breathing difficulties
  • Swollen face, mouth throat or tongue

Bacterial resistance

Incorrect use of an antibiotic may result in resistant bacteria that cannot be killed by the antibiotic being used, and it may not be effective in the future. That’s why it is important that patients continue to take the full course of antibiotics they have been prescribed, even if they begin to feel better. This will help your body to expel the infection and prevent the development of resistant bacteria. Antibiotics, such as Biaxin, should not be used to treat viral infections, like a common cold, as they do not kill viruses. Using antibiotics in this way can result in resistant bacteria developing.


Caused by the bacteria C. difficile, Clostridium difficile-associated diarrhea is a serious infection that is linked to Biaxin as well as other antibiotics. It can be up to 2 months after your final dose of Biaxin before it occurs. You should seek medical attention as soon as you can if you experience loose and watery bowel movements, particularly if they are green with a foul odor, or are bloody and you have a fever.

Dizziness, confusion, and disorientation

You should wait to see how this medication affects you before you drive a vehicle or operate machinery as Biaxin may cause dizziness, confusion, and disorientation.

Kidney function

Biaxin can accumulate in the body, resulting in side effects, if you suffer from reduced kidney function. You should discuss it with your doctor if your kidney function is compromised. Your doctor should let you know how taking Biaxin might impact your condition, how the dosing of the medication and its effectiveness may be affected by your condition, and whether you may need to be monitored.

Liver function

Biaxin can accumulate in the body, resulting in side effects, if you suffer from liver disease or compromised liver function. You should discuss it with your doctor if your liver function is compromised. Your doctor should let you know how taking Biaxin might impact your condition, how the dosing of the medication and its effectiveness may be affected by your condition, and whether you may need to be monitored. If you notice any symptoms of liver issues, you should let your doctor know as soon as possible. The symptoms include:

  • loss of appetite
  • nausea
  • vomiting
  • jaundiced skin or yellowing whites of the eyes
  • dark urine
  • abdominal pain
  • itchy skin

Pregnancy, breastfeeding, and children


Unless there is no alternative treatment, Biaxin should not be used during pregnancy, particularly during the first three months of pregnancy. You should contact your doctor if you are taking Biaxin when you become pregnant.


Biaxin does pass into breast milk and can impact your baby if you are breastfeeding while taking it. Discuss whether you should continue breastfeeding with your doctor.


Biaxin oral suspension has not been established as safe or effective for children under 6 months of age. Use of Biaxin oral suspension in children younger than 3 years with pneumonia has not been studied. The use of Biaxin in treating children under 20 months of age to prevent MAC infection has not been studied to establish safety and effectiveness. In children aged under 12, the safety and effectiveness of Biaxin has not been established.


Biaxin may interact with any of the following drugs, so if you are taking any of them you should let your doctor know or seek guidance from your pharmacist.

  • abiraterone acetate
  • aliskiren
  • almotriptan
  • alpha-blockers (e.g., alfuzosin, doxazosin, silodosin, tamsulosin)
  • amiodarone
  • anti-cancer medications (e.g., cabazitaxel, docetaxel, doxorubicin, etoposide, ifosfamide, irinotecan, vincristine)
  • anti-emetic medications (serotonin antagonists; e.g., granisetron, ondansetron)
  • antihistamines (e.g., cetirizine, doxylamine, diphenhydramine, hydroxyzine, loratadine)
  • antipsychotics (e.g., chlorpromazine, clozapine, haloperidol, olanzapine, quetiapine, risperidone)
  • apalutamide
  • apixaban
  • aprepitant
  • “azole” antifungals (e.g., itraconazole, ketoconazole, voriconazole)
  • bacillus Calmette-Guérin (BCG) vaccine
  • benzodiazepines (e.g., clonazepam, diazepam, lorazepam)
  • bicalutamide
  • bosentan
  • brinzolamide
  • bromocriptine
  • buprenorphine
  • buspirone
  • cabergoline
  • calcitriol
  • calcium channel blockers (e.g., amlodipine, diltiazem, nifedipine, verapamil)
  • cannabis
  • carbamazepine
  • carvedilol
  • chloroquine
  • cholera vaccine
  • cimetidine
  • cinacalcet
  • clopidogrel
  • cobicistat
  • colchicine
  • conivaptan
  • corticosteroids (e.g., dexamethasone, hydrocortisone, prednisone)
  • cyclosporine
  • dabigatran
  • dantrolene
  • darifenacin
  • deferasirox
  • degarelix
  • digoxin
  • disopyramide
  • divalproex
  • dofetilide
  • domperidone
  • donepezil
  • dronedarone
  • dutasteride
  • edoxaban
  • eletriptan
  • enzalutamide
  • eplerenone
  • ergot alkaloids (e.g., dihydroergotamine, ergonovine, ergotamine, methylergonovine)
  • estrogens (e.g., conjugated estrogen, estradiol, ethinyl estradiol, norethindrone)
  • ethosuximide
  • everolimus
  • fingolimod
  • flecainide
  • fentanyl
  • formoterol
  • galantamine
  • “gliptin” diabetes medications (e.g., linagliptin, saxagliptin, sitagliptin)
  • grapefruit juice
  • guanfacine
  • hepatitis C antivirals (e.g., asunaprevir, daclatasvir, grazoprevir)
  • HIV non-nucleoside reverse transcriptase inhibitors (NNRTIs; e.g., delavirdine, efavirenz, etravirine, nevirapine)
  • HIV protease inhibitors (e.g., atazanavir, indinavir, ritonavir, saquinavir)
  • indacaterol
  • insulin
  • ivermectin
  • lidocaine
  • lithium
  • lomitapide
  • loperamide
  • macitentan
  • other macrolide antibiotics (e.g., azithromycin, erythromycin)
  • maraviroc
  • medications used to treat diabetes (e.g., pioglitazone, rosiglitazone, repaglinide)
  • mefloquine
  • methadone
  • mifepristone
  • mirtazapine
  • modafinil
  • nadolol
  • narcotic pain relievers (e.g., codeine, fentanyl, morphine, oxycodone)
  • nefazodone
  • nitrates (e.g., isosorbide dinitrate, isosorbide mononitrate)
  • oxybutynin
  • pentamidine
  • phenobarbital
  • phenytoin
  • phosphodiesterase 5 inhibitors (e.g., sildenafil, tadalafil, vardenafil)
  • prasugrel
  • praziquantel
  • primidone
  • procainamide
  • progestins (e.g., dienogest, levonorgestrel, medroxyprogesterone, norethindrone)
  • propafenone
  • proton pump inhibitors (e.g., lansoprazole, omeprazole)
  • quinidine
  • quinine
  • quinolone antibiotics (e.g., ciprofloxacin, norfloxacin, ofloxacin)
  • ranitidine
  • rifabutin
  • rifampin
  • rifaximin
  • rilpivirine
  • rivaroxaban
  • romidepsin
  • salmeterol
  • selective serotonin reuptake inhibitors (SSRIs; e.g., citalopram, fluoxetine, paroxetine, sertraline)
  • serotonin-norepinephrine reuptake inhibitors (SNRIs; e.g., duloxetine, venlafaxine)
  • sirolimus
  • sodium picosulfate
  • sotalol
  • “statin” anti-cholesterol medications (e.g., atorvastatin, lovastatin, simvastatin)
  • John’s wort
  • sulfonylureas (e.g., glyburide, tolbutamide)
  • tacrolimus
  • tamoxifen
  • theophyllines (e.g., aminophylline, oxtriphylline, theophylline)
  • ticagrelor
  • tofacitinib
  • tolterodine
  • tolvaptan
  • tramadol
  • trazodone
  • tricyclic antidepressants (e.g., amitriptyline, clomipramine, desipramine, trimipramine)
  • trimethoprim
  • typhoid vaccine
  • tyrosine kinase inhibitors (e.g., dasatinib, imatinib, nilotinib)
  • ulipristal
  • valproic acid
  • vilanterol
  • warfarin
  • zidovudine
  • zopiclone

Frequently Asked Questions

It’s important that you do not give your prescribed Biaxin to anyone else. Even if they have the same symptoms as you, it can be harmful to them if they have not been prescribed it.

It is vital that you take Biaxin exactly as your doctor has prescribed, so if you miss a dose you should seek guidance from your doctor. However, do not attempt to give yourself two doses to make up for the one you missed.

Biaxin should not be disposed of in wastewater or thrown out in the rubbish. You should seek the recommendations of your pharmacist to determine how best to dispose of the medication in your area.

An interaction does not necessarily mean you need to stop taking one. You should speak with your doctor and they will be able to help you manage your medications.

It depends on the situation, but your doctor might suggest:

  • you stop taking the medication
  • you change to a different medication
  • change your dosage of Biaxin, the other medication, or both
  • leave things as they are.

Other medications may interact with Biaxin, you should inform your doctor of all prescription, over-the-counter and herbal medicines. They should be made aware of any supplements you’re taking. You should also tell your doctor if you smoke, use street drugs or consume caffeine products.

Many things might affect the dose you are prescribed. Your weight, other medical factors, and other medications you are on can have an impact. Do not take anything other than the dose you have been given by your doctor.

It is important that you continue to finish your prescribed course of Biaxin, even when you do begin to feel better.

Biaxin tablets should be stored at room temperature, between 68°F and 77°F, away from light, moisture and out of the reach of children.

Biaxin oral suspension should be kept in its tightly closed bottle and stored at room temperature, between 68°F and 77°F, not in the refrigerator. Unused Biaxin oral suspension should be disposed of 14 days after opening. If using a dose-measuring oral syringe, it should be rinsed after each use and the suspension should not be stored in the syringe.

There are alternatives to Biaxin, you can discuss them with your doctor as there may be other medications that are more appropriate for your condition.

If you think you or anyone else may have overdosed on Biaxin, you should seek medical assistance. Overdose symptoms can include:

  • Intense stomach pain
  • Nausea
  • Vomiting
  • Diarrhea

If someone has collapsed after using Biaxin, call for emergency medical assistance.

Yes, you will need a prescription, but it is refillable. Your doctor should state on your prescription the number of refills permitted.

Headaches are a common side effect when taking Biaxin. In clinical studies Biaxin was found to cause headaches in roughly 1% to 10% of patients.

Biaxin may be prescribed for conditions other than those mentioned above. If you do not know why your doctor has prescribed it for you, you should ask them. It is important not to stop taking Biaxin without discussing it with your doctor.

Alcohol should not reduce how effective Biaxin is, so you can safely drink alcohol. However, it is advisable that you avoid drinking alcohol while being treated for an infection as it can delay your recovery.