A-Z Drug Facts > Clarithromycin

Clarithromycin

Pronouncation: (kluh-RITH-row-MY-sin)
Class: Macrolide Antibiotic

Trade Names:
Biaxin
- Tablets 250 mg
- Tablets 500 mg
- Granules for oral suspension 125 mg per 5 mL after reconstitution
- Granules for oral suspension 250 mg per 5 mL after reconstitution

Trade Names:
Biaxin XL
- Tablets, extended-release 500 mg

Biaxin BID (Canada)

Pharmacology

Binds to the 50S ribosomal subunit of susceptible microorganisms resulting in inhibition of protein synthesis.

Pharmacokinetics

Absorption

Rapidly absorbed. Bioavailability is about 50%. T _max is 2 to 3 h. Steady state achieved within 3 days.

Distribution

Widely distributed.

Metabolism

Metabolized to 14-OH clarithromycin (active).

Elimination

The t _½ is about 3 to 4 h (250 mg) and 5 to 7 h (500 mg). 20% to 40% is excreted in urine as unchanged drug; 10% to 15% is excreted as 14-OH clarithromycin.

Indications and Usage

Adults

Treatment of pharyngitis/tonsillitis; acute maxillary sinusitis; acute bacterial exacerbation of chronic bronchitis; community-acquired pneumonia; uncomplicated skin and skin structure infections; disseminated mycobacterial infections; Helicobacter pylori and duodenal ulcer disease when used in combination with amoxicillin and lansoprazole or omeprazole; H. pylori and active duodenal ulcer when used in combination with omeprazole or ranitidine bismuth citrate; prevention of disseminated Mycobacterium avium complex (MAC) disease in patients with advanced HIV infection.

Children

Pharyngitis/tonsillitis; community-acquired pneumonia; acute maxillary sinusitis; acute otitis media; uncomplicated skin and skin structure infections; prevention of disseminated MAC disease in children with advanced HIV infection.

Contraindications

Patients receiving astemizole, cisapride, dihydroergotamine, ergotamine, pimozide, or terfenadine; hypersensitivity to clarithromycin, erythromycin, or any macrolide antibiotic.

Dosage and Administration

Active Duodenal Ulcer Associated with H. pylori infection
Adults

PO Immediate-release tablets/oral suspension: clarithromycin 500 mg, lansoprazole 30 mg, and amoxicillin 1 g every 12 h for 10 or 14 days; or clarithromycin 500 mg, omeprazole 20 mg, and amoxicillin 1 g every 12 h for 10 days then, for patients with ulcer present at time of initiation of therapy, omeprazole 20 mg once daily for additional 18 days; or clarithromycin 500 mg every 8 h and omeprazole 40 mg every day for 14 days then omeprazole 20 mg once daily for additional 14 days; or clarithromycin 500 mg every 12 or every 8 h and ranitidine bismuth citrate 400 mg every 12 h for 14 days, then ranitidine bismuth citrate 400 mg every 12 h for additional 14 days.

Acute Exacerbation of Chronic Bronchitis caused by H. influenza , H. parainfluenza , M. catarrhalis , or S. pneumoniae
Adults

PO Immediate-release tablets/oral suspension: H. influenza : 500 mg every 12 h for 7 to 14 days. H. parainfluenza : 500 mg every 12 h for 7 days; M. catarrhalis or S. pneumoniae : 250 mg every 12 h for 7 to 14 days.

Adults

PO Two extended-release 500 mg tablets every 24 h for 7 days.

Acute Maxillary Sinusitis caused by H. influenza
Adults

PO Immediate-release tablet/oral suspension 500 mg every 12 h or extended-release two 500 mg tablets every 24 h for 14 days.

Children 6 mo of age and older

PO 7.5 mg/kg (max, 500 mg) every 12 h for 10 days.

Acute Otitis Media
Children 6 mo of age and older

PO Immediate-release tablets/oral suspension 7.5 mg/kg (max, 500 mg) every 12 h for 10 days.

Community-Acquired Pneumonia caused by H. influenza , S. pneumoniae , C. pneumoniae , or M. pneumoniae
Adults

PO Immediate-release tablets/oral suspension: H. influenza : 250 mg every 12 h for 7 days; S. pneumoniae , C. pneumoniae , M. pneumoniae : 250 mg every 12 h for 7 to 14 days.

Children 6 mo of age and older

PO Immediate-release tablets/oral suspension 7.5 mg/kg (max, 500 mg) every 12 h for 10 days.

Community-acquired pneumonia caused by C. pneumoniae , H. influenzae , H. parainfluenzae , M. catarrhalis , M. pneumoniae , S. pneumoniae
Adults

PO Two extended-release 500 mg tablets every 24 h for 7 days.

Mycobacterial Infections
Adults

PO Immediate-release tablets/oral suspension 500 mg every 12 h for prevention and treatment.

Children 20 mo of age and older

PO Immediate-release tablets/oral suspension 7.5 mg/kg (max, 500 mg) every 12 h for prevention and treatment.

Pharyngitis/Tonsillitis caused by S. pyogenes
Adults

PO Immediate-release tablet/oral suspension 250 mg every 12 h for 10 days.

Children 6 months of age and older

PO 7.5 mg/kg (max, 500 mg) every 12 h for 10 days.

Uncomplicated Skin and Skin Structure Infections
Adults

PO Immediate-release tablets/oral suspension 250 mg every 12 h for 7 to 14 days.

Children 6 mo of age and older

PO 7.5 mg/kg (max, 500 mg) every 12 h for 10 days.

Renal Function Impairment
Adults

PO Halve the dose or double the dosing interval in patients with severe renal function impairment (Ccr less than 30 mL/min).

General Advice

• Administer immediate-release tablets and oral suspension without regard to meals. Administer with food if GI upset occurs.
• Administer extended-release tablets with food.
• Administer tablets with a full glass of water.
• Shake suspension well before measuring dose.
• Measure and administer oral suspension using dosing syringe, dosing syringe, or dosing cup.
• To constitute oral suspension, add 27 mL of water to 50 mL bottles and 55 mL of water to 100 mL bottles.

Storage/Stability

Store 250 mg immediate-release tablets and extended-release tablets at controlled room temperature (59° to 86°F). Protect from light. Store 500 mg immediate-release tablets at controlled room temperature (68° to 77°F).

Reconstituted suspension

Store at controlled room temperature (59° to 86°F). Keep tightly closed. Do not refrigerate suspension. Discard any unused suspension after 14 days.

Drug Interactions

Antiarrhythmic agents (eg, disopyramide, quinidine)

Risk of life-threatening cardiac arrhythmias, including torsades de pointes, may be increased.

Astemizole, terfenadine

Concurrent use is contraindicated.

Benzodiazepines (eg, midazolam, triazolam)

Increased and prolonged CNS effects.

Buspirone, cilostazol, corticosteroids (eg, methylprednisolone)

Plasma levels of these drugs may be elevated, increasing the pharmacologic and adverse effects.

Carbamazepine

May increase blood level concentrations of carbamazepine; recommend monitoring levels.

Cisapride, pimozide

Elevated plasma levels of these drugs and increased risk of serious cardiotoxicity, including arrhythmias and death may occur. Concurrent use is contraindicated.

Colchicine

Risk of colchicine toxicity may be increased, especially in the elderly.

Cyclosporine

Elevated cyclosporine levels with increased risk of toxicity.

Digoxin

Elevated serum digoxin levels may occur.

Eplerenone

Plasma concentrations of eplerenone may be elevated, increasing the risk of hyperkalemia and associated serious arrhythmias. Eplerenone is contraindicated in patients receiving clarithromycin.

Ergot derivatives (eg, ergotamine)

The risk of acute ergotism (eg, peripheral ischemia) may be increased.

Fluconazole, grapefruit juice, ritonavir

Clarithromycin plasma levels may be elevated, increasing the risk of side effects.

HMG-CoA reductase inhibitors (eg, lovastatin)

Increased risk of myopathy and rhabdomyolysis.

Lansoprazole, omeprazole, ranitidine bismuth citrate, repaglinide

Clarithromycin may increase plasma concentrations of these agents.

Rifamycins (eg, rifabutin)

Antimicrobial effects of clarithromycin may be decreased, while adverse effect of rifamycins may be increased.

Sildenafil

Plasma levels may be elevated by clarithromycin, increasing the risk of side effects.

Tacrolimus

Increased plasma levels with increased risk of toxicity.

Theophylline

May increase theophylline plasma concentration; recommend monitoring levels.

Verapamil

Risk of cardiotoxicity may be increased.

Warfarin

The anticoagulant effect may be increased, increasing the risk of hemorrhage.

Zidovudine

Serum levels may be increased or decreased by clarithromycin.

Laboratory Test Interactions

None well documented.

Adverse Reactions

Cardiovascular

QT prolongation, ventricular arrhythmias including ventricular tachycardia and torsades de pointes (postmarketing).

CNS

Headache (2%); anxiety, behavioral changes, confusional states, convulsions, depersonalization, disorientation, dizziness, hallucinations, insomnia, manic behavior, nightmares, psychosis, tinnitus, tremor, vertigo (postmarketing).

Dermatologic

Rash (3%); Stevens-Johnson syndrome, toxic epidermal necrolysis (postmarketing).

EENT

Hearing loss, alterations in sense of smell (postmarketing).

GI

Abnormal taste (7%); diarrhea, vomiting (6%); abdominal pain/discomfort, nausea (3%); dyspepsia (2%); anorexia, glossitis, oral moniliasis, pancreatitis, stomatitis, taste perversion or loss, tongue discoloration, tooth discoloration (postmarketing).

Genitourinary

Interstitial nephritis (postmarketing).

Hepatic

Hepatic dysfunction including increased liver enzymes, hepatocellular and/or cholestatic hepatitis with or without jaundice (postmarketing).

Hematologic-Lymphatic

Leukopenia, neutropenia, thrombocytopenia (postmarketing).

Lab Tests

Elevated alkaline phosphatase, ALT, AST, BUN, gamma-glutamyltransferase, LDH, serum creatinine, total bilirubin, PT, decreased WBC (postmarketing).

Metabolic-Nutritional

Hypoglycemia (postmarketing).

Miscellaneous

Allergic reactions ranging from urticaria and mild skin eruptions to anaphylaxis (postmarketing).

Precautions

Monitor Monitor patient's response to therapy. Monitor patient for GI, DERM, and general body side effects, and signs of superinfection. Inform health care provider if noted and significant. Immediately report severe diarrhea, diarrhea containing blood or pus, or severe abdominal cramping.

Pregnancy

Category C .

Lactation

Undetermined.

Children

Safety and efficacy in children younger than 6 mo of age not established. Safety in treatment of MAC in children younger than 20 mo of age not established.

Elderly

Consider dosage adjustments in elderly patients with severe renal function impairment.

Renal Function

Use with caution and consider reduced dose or prolonged dosing intervals in patients with severe renal function impairment. Clarithromycin in combination with ranitidine bismuth citrate therapy is not recommended in patients with Ccr less than 25 mL/min.

Pseudomembranous colitis

Consider possibility in patients in whom diarrhea develops.

Overdosage

Symptoms

Abdominal pain, diarrhea, nausea, vomiting.

Patient Information

• Advise patient to review the patient information leaflet carefully before starting therapy and to read and check for new information each time the medication is refilled.
• Review dosing schedule and prescribed length of therapy with patient.
• Reinforce to patient or caregiver the need to take exactly as prescribed and complete the entire course of therapy, even if symptoms of infection have disappeared. Caution patient or caregiver that skipping doses or not completing the full course of therapy may allow the infection to worsen and increase the possibility that the bacteria will become resistant to the antibiotic and may cause infections that will not be treatable in the future.
• Advise patient using immediate-release tablets or oral suspension that medication can be taken without regard to meals but to take with food if GI upset occurs.
• Advise patient using extended-release tablets to take each dose with food. Caution patient to swallow whole and not to chew, crush, split, or break the tablet.
• Instruct patient to take tablets with a full glass of water.
• Instruct patient or caregiver using oral suspension to shake well before measuring dose and to use dosing spoon, dosing syringe, or dosing cup to measure and administer dose.
• Advise patient that if a dose is missed to take as soon as remembered; however, if it is nearing the time for the next dose to skip the dose and take the next dose at the regularly scheduled time.
• Advise patient to discontinue therapy and contact health care provider immediately if fainting, hives, itching, shortness of breath, skin rash, or palpitations occur.
• Advise patient to report the following signs of superinfection to health care provider: black “furry” tongue, white patches in mouth, foul-smelling stools, vaginal itching or discharge.
• Warn patient that diarrhea containing blood or pus may be a sign of a serious disorder and to seek medical care if noted and not treat at home.

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