Klacid MR 500 mg modified-release film-coated tablets – clarithromycin for bacterial infections

Klacid MR contains clarithromycin, an antibiotic from the macrolide group. Antibiotics stop the growth of bacteria that cause infections; they do not work against viral infections such as colds and flu.

“MR” means it is a 500 mg modified-release film-coated tablet taken once a day with food. It is intended for adults and children aged 12 years and older.

What is Klacid MR used for and how is it taken correctly?

Key facts about the medicine

What is Klacid MR used for?

According to the leaflet and SmPC, Klacid MR is used to treat infections caused by bacteria sensitive to clarithromycin, taking into account official guidance on antibiotic use:

• lower respiratory tract infections – acute and chronic bronchitis and pneumonia;
• throat and sinus infections;
• mild to moderate skin and soft tissue infections (e.g. folliculitis, cellulitis, erysipelas).

How is Klacid MR taken and dosed?

• Adults and children aged 12 and older: usually one 500 mg tablet once a day; for severe infections the doctor may increase the dose to two tablets a day.
• The usual duration of treatment is 6 to 14 days.
• Take the tablets with food and swallow them whole – do not chew or break them.
• Take the medicine for as long as your doctor has prescribed, even if you feel better, because symptoms may return.

Special patient groups

• Children under 12 years: the medicine is not intended for this group; the doctor will choose another form.
• Kidney impairment: with creatinine clearance 30–60 mL/min a maximum of one tablet a day; with clearance below 30 mL/min Klacid MR is contraindicated (other forms of clarithromycin are used).
• Liver impairment: caution is needed; the medicine must not be used in severe liver impairment combined with kidney impairment.
• Elderly patients: dosing is decided by the doctor according to kidney function.

Contraindications – when the medicine must not be used

• allergy to clarithromycin, other macrolides (erythromycin, azithromycin) or any of the excipients;
• concomitant use of ergot alkaloids (ergotamine, dihydroergotamine), terfenadine, astemizole, cisapride, pimozide, lovastatin, simvastatin, oral midazolam, ticagrelor, ranolazine or colchicine;
• other medicines known to cause serious heart rhythm disorders;
• low blood potassium (hypokalaemia);
• severe liver disease combined with kidney disease;
• QT prolongation or ventricular arrhythmias (including torsades de pointes) in your own or family history;
• creatinine clearance below 30 mL/min (for this form).

Warnings and precautions

• heart disease (heart failure, slow heart rate) or low blood magnesium;
• liver or kidney problems;
• tendency to fungal infections (e.g. thrush);
• pregnancy and breast-feeding;
• myasthenia gravis – clarithromycin may worsen symptoms;
• the medicine contains lactose and 15.3 mg of sodium per tablet.

Interactions with other medicines, food and drink

• digoxin, quinidine, disopyramide; warfarin and other anticoagulants;
• carbamazepine, valproate, phenobarbital, phenytoin; theophylline; ibrutinib, vinblastine;
• atorvastatin, rosuvastatin (risk of rhabdomyolysis); diabetes medicines (insulin, repaglinide, nateglinide, pioglitazone, rosiglitazone, gliclazide, glimepiride);
• triazolam, alprazolam, IV or oromucosal midazolam; cilostazol, methylprednisolone; ciclosporin, sirolimus, tacrolimus;
• HIV antiviral medicines, rifabutin, rifampicin, rifapentine, fluconazole, itraconazole; tolterodine;
• verapamil, amlodipine, diltiazem; sildenafil, vardenafil, tadalafil;
• St John’s wort, quetiapine and other antipsychotics, other macrolides, lincomycin and clindamycin;
• oral contraceptives – if diarrhoea or vomiting occur, additional protection (e.g. condoms) is needed.

Pregnancy and breast-feeding

• The safety of use during pregnancy and breast-feeding has not been established; always consult your doctor before taking it. According to the SmPC, doctors prescribe clarithromycin to pregnant women only after careful benefit–risk assessment, especially in the first three months.

Driving and using machines

• The medicine may cause dizziness or drowsiness; if this happens, do not drive or operate machinery.

Possible side effects

• Common: sleep problems, change in taste, headache, widening of blood vessels, nausea, vomiting, abdominal pain, indigestion, diarrhoea, increased sweating.
• Uncommon: fever, itching and rash, oral or vaginal thrush, gastroenteritis, blood count changes, loss of appetite, nervousness, dizziness, ringing in the ears, palpitations, dry mouth, constipation, abnormal liver and kidney tests.
• Not known: pseudomembranous colitis, confusion and hallucinations, convulsions, loss of taste or smell, heart rhythm disorders (torsades de pointes), pancreatitis, tongue or tooth discolouration, acne, kidney dysfunction.

Overdose, missed dose and stopping treatment

• Overdose: seek medical help immediately; the most likely signs are vomiting and abdominal pain.
• Missed dose: take it as soon as you remember, but do not take more tablets in a day than your doctor prescribed.
• Stopping treatment: do not stop early, even if you feel better – the infection may come back.

Related information

For additional care and support with maintaining the gut flora during and after antibiotic treatment, see also the category Products with probiotics – products in this category do not replace the medicine you have been prescribed.

Composition, pack and manufacturer

• Active substance: clarithromycin 500 mg per modified-release film-coated tablet.
• Excipients: core – anhydrous citric acid, sodium alginate, sodium calcium alginate, lactose monohydrate, povidone, talc, stearic acid, magnesium stearate; coating – hypromellose, macrogols, titanium dioxide, quinoline yellow (E104), sorbic acid.
• Appearance: oblong yellow film-coated tablets.
• Pack: 7 film-coated tablets (1 PVC/PVDC-Al blister).
• Marketing authorisation holder: Viatris Healthcare d.o.o., Belgrade (transfer 515-01-00223-21-001 of 24.06.2021); manufacturer: AbbVie S.r.l., Campoverde di Aprilia, Italy.
• Authorisation number: 515-01-00522-19-001 of 03.10.2019 (renewal).

Storage

• Store below 30 °C in the original package to protect from light.
• Keep out of the sight and reach of children.
• Do not use after the expiry date; return unused medicine to a pharmacy that collects unused medicines.

Frequently asked questions

What is the difference between Klacid MR and regular Klacid 500 mg?

Klacid MR is a modified-release tablet taken once a day with food, while immediate-release tablets are taken on a different schedule. The dosing of one form must not be transferred to the other.

Can I split a Klacid MR tablet?

No. The tablets are swallowed whole, without chewing or breaking, because this would disrupt the modified release of the medicine.

How long does treatment with Klacid MR last?

Usually 6 to 14 days, as decided by the doctor. Do not stop treatment early even if you feel better.

Can I take Klacid MR with cholesterol medicines?

Simvastatin and lovastatin must not be taken with clarithromycin; atorvastatin and rosuvastatin require caution and monitoring for muscle pain. Any combination is decided by your doctor.

Sources

• ALIMS – Package leaflet Klacid MR 500 mg (PIL, Serbian)
• ALIMS – Summary of product characteristics Klacid MR (SmPC, Serbian)

Date sources were checked: 25.10.2026.