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Clarithromycin oral modified release

Updated 2 Feb 2023 | Macrolides


Modified release tablets containing clarithromycin

Drugs List

  • clarithromycin 500mg modified release tablet
  • KLARICID XL 500mg modified release tablet
  • XETININ XL 500mg prolonged release tablet
  • Therapeutic Indications


    Lower respiratory tract infections
    Skin and soft tissue infections
    Upper respiratory tract infections

    Treatment of infections caused by susceptible organisms. Types of infection include:

    Lower respiratory tract infections - acute and chronic bronchitis, pneumonia
    Upper respiratory tract infections - Tonsillitis, sinusitis and pharyngitis
    Mild to moderate skin and soft tissue infections - folliculitis, cellulitis, erysipelas

    Clarithromycin is usually effective against the following:
    Gram positive bacteria - Staphylococcus aureus (methicillin susceptible), Streptococcus pyogenes (Group A beta-haemolytic streptococci), alpha-haemolytic streptococcus (viridans group), Streptococcus (Diplococcus) pneumoniae, Streptococcus agalactia, Listeria monocytogenes.
    Gram negative bacteria - Haemophilus influenzae, Haemophilus parainfluenzae, Moraxella (Branhamella) catarrhalis, Neisseria gonorrhoeae; Legionella pneumophila, Bordetella pertussis, Campylobacter jejuni.
    Mycoplasma - Mycoplasma pneumoniae; Ureaplasma urealyticum.
    Other organisms - Chlamydia trachomatis; Mycobacterium avium; Mycobacterium leprae, Chlamydia pneumoniae
    Anaerobes - Macrolide-susceptible Bacteroides fragilis; Clostridium perfringens; Peptococcus species; Peptostreptococcus species; Propionbacterium acnes.



    500 mg daily.

    The dosage may be increased to 1000 mg daily in more severe infections.

    The usual duration of treatment is 6 to 14 days.


    500 mg daily.

    The dosage may be increased to 1000 mg daily in more severe infections.

    The usual duration of treatment is 6 to 14 days.


    Children over 12 years of age
    500 mg daily.

    The dosage may be increased to 1000 mg daily in more severe infections.

    The usual duration of treatment is 6 to 14 days.

    Children under 12 years of age
    Contraindicated. Modified release preparations should not be used in these patients. Oral liquids may be used instead.

    Patients with Renal Impairment

    Use with caution as clarithromycin is principally excreted by the kidney.

    See information for clarithromycin standard release oral preparations for dose adjustment in renal impairment.

    Creatinine clearance 30 to 60 ml/minute
    One manufacturer suggests a maximum dose of 500 mg per day.

    Creatinine clearance less than 30 ml/minute
    Contraindicated. Modified release preparations should not be used in these patients as dosage adjustment is not easily managed. Standard release preparations should be used instead as adjustment of the dose is more practicable.


    For oral administration to be taken with food at the same time each day. Tablets must be swallowed whole and not chewed.


    Children under 12 years
    Family history of long QT syndrome
    Electrolyte imbalance
    History of torsade de pointes
    History of ventricular arrhythmias
    Long QT syndrome
    Renal impairment - creatinine clearance below 30 ml/minute
    Severe hepato-renal syndrome
    Ventricular arrhythmias

    Precautions and Warnings

    Bradycardia with pulse rate at rest < 50 beats per minute
    Glucose-galactose malabsorption syndrome
    Hepatic impairment
    Lactose intolerance
    Myasthenia gravis
    Renal impairment - creatinine clearance 30-60ml/minute

    May exacerbate myasthenia gravis
    Advise ability to drive/operate machinery may be affected by side effects
    Consult national/regional policy on the use of anti-infectives
    Ineffective for H. influenzae infections with concurrent tipranavir
    Contains lactose
    Take cultures for sensitivity testing before and regularly during treatment
    Consider pseudomembranous colitis if patient presents with severe diarrhoea
    Advise patients to report signs of hepatic damage (malaise, jaundice etc.)
    Prolonged use may result in superinfection with non-susceptible organisms
    Discontinue if overgrowth of resistant organisms occurs
    Discontinue if severe hypersensitivity reactions occur
    Discontinue if symptoms of hepatic disease occur
    Discontinue therapy if marked diarrhoea occurs
    Advise patient not to take St John's wort concurrently

    Due to a risk of prolonged QT interval, clarithromycin should not be used in patients with the following conditions:
    Coronary artery disease
    History of ventricular arrhythmia
    Severe cardiac impairment
    Bradycardia (less than 50 bpm)
    Electrolyte disturbances

    Sensitivity testing should be performed when prescribing clarithromycin for community-acquired pneumonia due to emerging resistance of Streptococcus pneumoniae to macrolides. In hospital-acquired pneumonia, clarithromycin should be used in combination with additional appropriate antibiotics.

    Before initiating treatment for skin and soft tissue infections of mild to moderate severity, sensitivity testing should be performed. Skin and soft tissue infections are most often caused by Staphylococcus aureus and Streptococcus pyogenes, both of which may be resistant to macrolides. Currently, macrolides are only considered appropriate in some skin and soft tissue infections, such as those caused by Corynebacterium minutissimum (erythrasma), acne vulgaris, erysipelas and in situations where penicillin treatment cannot be used.

    Cases of fatal hepatic failure have been reported. Some patients may have had pre-existing hepatic disease or may have been taking other hepatotoxic medicinal products. Patients should be advised to stop treatment and contact their doctor if signs and symptoms of hepatic disease develop, such as anorexia, jaundice, dark urine, pruritis, or tender abdomen.

    Clarithromycin inhibits the enzyme CYP3A4, which is involved in the metabolism of colchicine. Therefore if these drugs are given concurrently, colchicine toxicity may occur. Toxicity is more likely to occur in the elderly or in those with renal impairment and death has occurred in some cases. If these drugs are administered concurrently, the patient should be monitored for signs of colchicine toxicity.

    Clarithromycin may cause antibiotic-associated diarrhoea (including Clostridium difficile associated diarrhoea), colitis and pseudomembranous colitis. If diarrhoea occurs during or soon after treatment then these diagnoses should be considered. Careful medical history is necessary since Clostridium difficile associated diarrhoea has been reported to occur over two months after the administration of antibacterial agents. If severe or bloody diarrhoea occurs during treatment, clarithromycin should be discontinued and appropriate therapy instituted. Appropriate fluid and electrolyte management, protein supplementation, antibiotic treatment of Clostridium difficile, and surgical evaluation should be instituted as clinically indicated.

    Pregnancy and Lactation


    Use clarithromycin with caution during pregnancy.

    Briggs reports the available human pregnancy data on the use of clarithromycin during pregnancy suggests that the risk, if it exists, is low. However the animal reproduction data suggest high risk. Schaefer suggests clarithromycin is a second choice macrolide for use during pregnancy. The manufacturers suggest clarithromycin should not be used during pregnancy unless the benefits outweigh the risks.

    Safety in human pregnancy has not been established. Clarithromycin crosses the human placenta. The mean transplacental transfer of clarithromycin was 6.1% in an in vitro experiment using perfused term placentas. The possibility of adverse effects on embryofoetal development cannot be excluded based on variable results obtained from studies in mice, rats, rabbits and monkeys.

    The use of all medication in pregnancy should be avoided whenever possible; particularly in the first trimester. Non-drug treatments should also be considered. When essential, a medication with the best safety record over time should be chosen, employing the lowest effective dose for the shortest possible time. Polypharmacy should be avoided. Teratogens taken in the pre-embryonic period, often quoted as lasting until 14 to 17 days post-conception, are believed to have an all-or-nothing effect. Where drugs have a short half-life, and when the date of conception is certain, this may allow women to be reassured where drug exposure has occurred within this time frame. Further advice may be available from the UK National Teratology Information Service (NTIS) and through ToxBase, available via password on the internet ( ) or if this is unavailable at the backup site ( ).


    Use clarithromycin with caution in breastfeeding.

    Drugs and Lactation Database (LactMed) considers clarithromycin acceptable during breastfeeding due to low levels of clarithromycin in breast milk. The small amounts in milk are unlikely to cause adverse effects in the infant. However, the infant should be monitored for possible effects on the gastrointestinal flora, such as diarrhoea, thrush or nappy rash. Unconfirmed epidemiologic evidence indicates that the risk of hypertrophic pyloric stenosis in infants might be increased by maternal use of macrolide antibiotics during breastfeeding. The manufacturers suggest clarithromycin should not be used in breastfeeding unless the benefits outweigh the risks.

    Clarithromycin and its active metabolite are excreted in human breast milk.

    Neonates, infants born prematurely, those with low birth weight, those with an unstable gastrointestinal function or who have serious illnesses may require special consideration. For any infant, if a drug is prescribed to the nursing mother, it should be at the lowest practical dose and for the shortest time. When drug administration is unavoidable and breastfeeding is to continue, minimisation of exposure of the infant to the drug may sometimes be achieved by timing the maternal doses to just after a feeding episode. Infants exposed to drugs via breast milk should be monitored for unusual signs or symptoms. Interactions between the drug received by the infant from the mother's milk and medication prescribed for the infant should also be considered, for example, when the drug given to the infant may prevent metabolism of the drug received via breast milk.
    Specialist advice is available from the UK Drugs in Lactation Advisory Service at

    Side Effects

    Abdominal pain
    Abnormal INR
    Alanine aminotransferase increased
    Altered liver function tests
    Anaphylactic reaction
    Aspartate aminotransferase increased
    Blood urea increased
    Cardiac disorders
    Chest pain
    CNS effects
    Decreased appetite
    Discolouration of teeth and tongue
    Dream abnormalities
    Exacerbation of myasthenia gravis
    Gastro-intestinal symptoms
    Gastroesophageal reflux disease
    Hearing loss
    Hepatic failure
    Hepatic impairment
    Hypersensitivity reactions
    Increase in alkaline phosphatase
    Increase in lactate dehydrogenase
    Increases in hepatic enzymes
    Interstitial nephritis
    Loss of consciousness (transient)
    Musculoskeletal disturbances
    Overgrowth by non-susceptible organisms
    Prolongation of QT interval
    Prothrombin time increased
    Pseudomembranous colitis
    Psychotic disorder
    Pulmonary embolism
    Renal failure
    Serum creatinine increased
    Skin disorder
    Smelling disturbances
    Stevens-Johnson syndrome
    Taste disturbances
    Torsades de pointes
    Toxic epidermal necrolysis
    Urine abnormality
    Ventricular tachycardia
    Vulvovaginal infections


    It is strongly recommended that the UK National Poisons Information Service be consulted on cases of suspected or actual overdose where there is doubt over the degree of risk or about appropriate management.

    The following number will direct the caller to the relevant local centre (0844) 892 0111

    Information may be obtained if you have access to ToxBase the primary clinical toxicology database of the National Poisons Information Service. This is available via password on the internet ( ) or if this is unavailable at the backup site ( ).

    Further Information

    Last Full Review Date: September 2013

    Reference Sources

    British National Formulary, 66th Edition (September 2013-March 2014) Pharmaceutical Press, London.

    BNF for Children (2013-2014) Pharmaceutical Press, London.

    Drugs During Pregnancy and Lactation: Treatment Options and Risk Assessment, 2nd edition (2007) ed. Schaefer, C., Peters, P. and Miller, R. Elsevier, London.

    Drugs in Pregnancy and Lactation: A Reference Guide to Fetal and Neonatal Risk, 9th edition (2011) ed. Briggs, G., Freeman, R. and Yaffe, S. Lippincott Williams & Wilkins, Philadelphia.

    Medications and Mothers' Milk, 14th Edition (2010) Hale, T. Hale Publishing, Amarillo, Texas.

    Summary of Product Characteristics: Febzin XL tablets. Actavis. Revised November 2011.
    Summary of Product Characteristics: Klaricid XL tablets. Abbott Laboratories Limited. Revised September 2016.
    Summary of Product Characteristics: Xetinin XL tablets. Morningside Healthcare. Revised February 2011.

    US National Library of Medicine. Toxicology Data Network. Drugs and Lactation Database (LactMed).
    Available at:
    Clarithromycin. Last revised: September 7, 2013
    Last accessed: September 10, 2013.

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