Biaxin 500 mg Tablets

Brand name

The drug is known in the pharmaceutical market under the trade name Biaxin. This registered name is used to identify the drug in pharmacies and medical institutions.

International Nonproprietary Name (INN)

The international nonproprietary name of this medicine is clarithromycin. It reflects the active substance that provides the therapeutic effect.

Form of release

The drug is available in several forms to meet different clinical needs:

• Film-coated tablets with dosages of 250 mg and 500 mg of the active substance.
• Granules for preparation of suspension for oral administration with a concentration of 125 mg/5 ml or 250 mg/5 ml after dilution.
• Liofilizate for preparation of solution for intravenous administration (500 mg in a vial).

The variety of forms allows to adapt the therapy to the age of the patient and the severity of the condition.

Composition

The main active substance is clarithromycin, an antibiotic from the group of macrolides. Auxiliary components depend on the form of release. In tablets, the following are used:

• Croscarmellose sodium - disintegrant for rapid dissolution.
• Microcrystalline cellulose - filler.
• Magnesium stearate - lubricant.
• Film shell (hypromellose, titanium dioxide, polyethylene glycol).

Saccharose, flavorings (e.g., vanilla), xanthan gum as a stabilizer are added to the suspension. The lyophilizate contains citric acid and sodium hydroxide to adjust the pH.

Pharmacologic Properties

Pharmacodynamics

The drug has bacteriostatic action, inhibiting protein synthesis in bacterial cells by binding to the 50S-subunit of ribosomes. This inhibits the multiplication of microorganisms. In high concentrations or against certain strains, a bactericidal effect may be seen. It is active against Gram-positive (Streptococcus pneumoniae, Staphylococcus aureus) and Gram-negative bacteria (Haemophilus influenzae, Moraxella catarrhalis), as well as atypical pathogens (Mycoplasma pneumoniae, Chlamydia pneumoniae, Legionella spp.).

The drug is also effective against Helicobacter pylori as part of combination therapy for peptic ulcer disease.

Pharmacokinetics

Absorption

After oral administration, the active substance is rapidly absorbed in the gastrointestinal tract. The maximum concentration is reached in 2-3 hours. Bioavailability is about 50% due to the effect of first passage through the liver. Food intake slows absorption but does not affect overall efficacy.

Distribution

The compound penetrates well into tissues including lungs, tonsils, skin and mucous membranes. Binding to plasma proteins is about 65-70%. Concentrations in tissues often exceed plasma concentrations, which enhances the therapeutic effect.

Metabolism

Metabolism occurs in the liver with the participation of cytochrome P450 (CYP3A4) enzymes, forming the active metabolite - 14-hydroxyclarithromycin, which also has antibacterial activity.

Excretion

It is excreted via the kidneys (20-30% unchanged) and with bile. The elimination half-life is 3-7 hours for the main substance and 5-9 hours for the metabolite, which depends on the dose and renal function.

Indications for Use

The drug is prescribed for the treatment of infections caused by sensitive microorganisms:

• Infections of the upper respiratory tract: pharyngitis, tonsillitis, sinusitis.
• Infections of the lower respiratory tract: bronchitis, pneumonia.
• Infections of the skin and soft tissues: folliculitis, rye, impetigo.
• Medium otitis media in children and adults.
• Gastric and duodenal ulcer disease associated with Helicobacter pylori (in combination).
• Disseminated infections caused by Mycobacterium avium in immunodeficient patients

Application requires confirmation of the sensitivity of the pathogen.

Contraindications

The use of the drug is prohibited in:

• Hypersensitivity to macrolides or components of the composition.
• Severe hepatic insufficiency in combination with renal dysfunction.
• Concurrent use with cisapride, pimozide, terfenadine (risk of arrhythmias).
• Lengthening of the QT interval or a history of arrhythmias.

Cautious administration in myasthenia gravis and electrolyte imbalance.

Method of Administration and Dosage

How to take

Tablets are taken orally, drinking water (about 150 ml), regardless of meals. Suspension is prepared by adding water to the mark on the bottle, shake before use. Solution for infusion is administered by intravenous drip within 60 minutes after dilution in physiologic solution.

Dosages for adults and children

Dosage depends on infection and age:

• Adults: 250-500 mg every 12 hours, course 7-14 days.
• Children over 6 months of age: 7.5 mg/kg body weight every 12 hours (suspension).
• Intravenously: 500 mg every 12 hours in severe conditions.

Dose adjustment for certain conditions

In renal failure:

• Creatinine clearance 30-60 mL/min: standard dose.
• Clearance less than 30 mL/min: reduce dose by 50% or increase interval to 24 hours.

In hepatic impairment, no correction is necessary if the kidneys are functioning normally.

Side Effects

Possible adverse reactions include:

• Gastrointestinal: nausea, diarrhea, taste changes, abdominal pain.
• Nervous: headache, insomnia, anxiety.
• Skin: rash, itching, rarely - severe allergic reactions.
• hepatic: increase in transaminases, jaundice (rare).
• Cardiac: QT prolongation (if predisposed).

Discontinue use if symptoms are severe.

Overdose

Symptoms of overdose

Exceeding the dose causes nausea, vomiting, confusion, arrhythmias, hypokalemia.

First aid measures

For overdose:

• Stop taking.
• Rinse the stomach (if it has been less than 2 hours).
• Provide symptomatic treatment (ECG monitoring, hydration).
• Refer to a physician.

Drug Interactions

Influence on the effects of other drugs

The medication affects:

• Statins (atorvastatin): increased risk of myopathy.
• Barfarin: increase in anticoagulant effect.
• Carbamazepine: increase in blood concentrations.

Compatibility with alcohol and food

Alcohol may increase liver side effects and should be avoided. Food does not affect efficacy, but fatty meals slow absorption.

Special Precautions

Use in pregnancy and breastfeeding

The use in pregnancy is possible only in strict indications (category C). The active substance penetrates into breast milk, therefore lactation is suspended for the period of treatment.

Effects on driving and mechanisms

Dizziness or confusion may make it difficult to drive or operate machinery.

Particularities of use in the elderly and children

In the elderly, renal dysfunction occurs more often, monitoring is required. In children, the drug is safe from 6 months of age with proper dosage.