BACTRID 457 ORAL SUSPENSION

Indications

• Acute otitis media
• Sinusitis
• Pneumonia
• Bronchitis
• Urinary tract infections
• Skin infections
• Gastrointestinal infections

Dosage

Children: Refer to BNF for Children for appropriate dosing information in paediatric patients.

Adults: Refer to specific clinical guidelines for adult dosing, as it varies based on infection type and severity.

Mechanism of action

Amoxicillin exerts its antibacterial effect by binding to penicillin-binding proteins (PBPs) located inside the bacterial cell wall. This binding interferes with the transpeptidation reaction, which is essential for cross-linking peptidoglycan layers, resulting in a weakened cell wall and eventual cell lysis.

Pharmacodynamics

The pharmacodynamic profile of amoxicillin demonstrates its bactericidal activity, which is concentration-dependent. The minimum inhibitory concentration (MIC) determines its effectiveness against specific pathogens. Amoxicillin is generally more effective against actively dividing bacteria, as it targets the cell wall synthesis process occurring during bacterial growth.

Pharmacokinetics

Amoxicillin is rapidly absorbed after oral administration, with peak plasma concentrations achieved within 1 to 2 hours. It has good bioavailability, typically around 70-90%. Amoxicillin is widely distributed throughout body tissues and fluids, including the lungs, kidneys, and middle ear. It is metabolized in the liver to a minor extent, and approximately 60-70% of the dose is excreted unchanged in the urine. Its half-life ranges from 1 to 1.5 hours, allowing for frequent dosing.

Contra-indications

• History of hypersensitivity to penicillins or any component of the formulation
• Severe renal impairment (creatinine clearance less than 30 mL/min) without dose adjustment
• Previous history of amoxicillin-associated cholestatic jaundice or hepatic dysfunction

Adverse effects

• Nausea
• Vomiting
• Diarrhoea
• Rash
• Allergic reactions (e.g., urticaria, anaphylaxis)
• Clostridium difficile-associated diarrhoea
• Hepatic dysfunction (elevated liver enzymes)
• Renal toxicity (interstitial nephritis)

Interactions

• Probenecid may increase serum concentrations of amoxicillin
• Allopurinol increases the likelihood of skin rashes
• Anticoagulants (e.g., warfarin) may have increased effects
• Oral contraceptives may have reduced efficacy when taken with amoxicillin

Precautions

• Use with caution in patients with a history of gastrointestinal diseases, particularly colitis
• Monitor for signs of anaphylaxis in patients with a history of allergies
• Adjust dosage in patients with renal impairment
• Consider the potential for superinfection with prolonged use

Pregnancy

Amoxicillin is categorized as pregnancy category B. Animal studies have not demonstrated a risk to the fetus, but there are no well-controlled studies in pregnant women. Use should be considered if the benefits outweigh the risks.

Breast-feeding

Amoxicillin is excreted in breast milk in small amounts. It is generally considered safe for use during breastfeeding, but monitor for potential effects on the infant, such as diarrhea or rash.

Storage

Store at room temperature, away from light and moisture. Reconstituted solutions should be stored in the refrigerator and used within the recommended time frame.

Formulations

• Tablets (250 mg, 500 mg)
• Capsules (250 mg, 500 mg)
• Oral suspension (125 mg/5 mL, 250 mg/5 mL)
• Injection (1 g vial)

Indications

• Bacterial infections caused by beta-lactamase producing organisms
• Community-acquired pneumonia
• Respiratory tract infections
• Urinary tract infections
• Skin and soft tissue infections

Dosage

Children: Paediatric dosing of clavulanate should be determined based on the specific indication and the formulation used. Refer to the BNF for

Adults: The usual adult dose of clavulanate varies depending on the specific antibiotic it is combined with, generally ranging from 125 mg to 250 mg, taken every 8 hours when combined with amoxicillin.

Mechanism of action

Clavulanate works by irreversibly binding to the active site of beta-lactamase enzymes. By inhibiting these enzymes, clavulanate protects beta-lactam antibiotics from degradation, allowing them to exert their antibacterial effects effectively. This mechanism enhances the spectrum of activity of the co-administered antibiotic, thereby improving clinical outcomes in infections caused by beta-lactamase producing organisms.

Pharmacodynamics

Clavulanate exhibits a time-dependent antibacterial effect, characterized by its ability to maintain effective concentrations against beta-lactamase producing bacteria. Its pharmacodynamic properties are mainly influenced by its interaction with beta-lactam antibiotics, enhancing their efficacy in treating infections. The overall effect is a synergistic relationship that increases the potency of the antibiotic treatment.

Pharmacokinetics

Clavulanate is usually administered orally or parenterally, and it is rapidly absorbed from the gastrointestinal tract. It reaches peak plasma concentrations within 1 to 2 hours after administration. The drug is widely distributed in body tissues, with a volume of distribution indicative of good tissue penetration. Clavulanate undergoes hepatic metabolism, primarily by conjugation, and is excreted largely in the urine as metabolites. The elimination half-life is approximately 1 hour, necessitating frequent dosing for optimal therapeutic effect.

Contra-indications

• Hypersensitivity to clavulanate or any component of the formulation
• History of jaundice or hepatic impairment related to previous use of beta-lactam antibiotics

Adverse effects

• Diarrhea
• Nausea
• Vomiting
• Rash
• Hepatic dysfunction
• Allergic reactions

Interactions

• Probenecid may increase concentrations of clavulanate
• Anticoagulants may have altered effects due to changes in gut flora

Precautions

• Monitor liver function during prolonged therapy
• Use cautiously in patients with renal impairment
• Assess for history of allergy to penicillins or cephalosporins

Pregnancy

Clavulanate is classified as category B. Animal studies have not shown teratogenic effects, but adequate and well-controlled studies in pregnant women are lacking.

Breast-feeding

Clavulanate is excreted in breast milk. Caution is advised when administering to nursing mothers.

Storage

Store in a cool, dry place away from direct light. Keep out of reach of children.

Formulations

• Clavulanate potassium 125 mg/5 mL
• Clavulanate potassium 250 mg/5 mL

Indications

• Infections caused by beta-lactamase-producing bacteria
• Acute bacterial sinusitis
• Acute otitis media
• Lower respiratory tract infections
• Urinary tract infections

Dosage

Children: Refer to the BNF for Children for specific dosing according to age and weight; adjustments may be necessary based on the clinical scenario.

Adults: Refer to specific product guidelines for dosing; typical regimens depend on the combination antibiotic used and the severity of the infection.

Mechanism of action

Clavulanic acid works by irreversibly binding to the active site of beta-lactamase enzymes that are produced by certain bacteria to inactivate beta-lactam antibiotics. By inhibiting these enzymes, clavulanic acid protects the penicillin antibiotic from degradation, allowing it to exert its antibacterial effects.

Pharmacodynamics

Clavulanic acid has a synergistic effect when combined with other antibiotics, particularly amoxicillin. The presence of clavulanic acid allows for the effective treatment of infections caused by bacteria that would otherwise be resistant to penicillins. Its antibacterial activity is generally weak on its own but significantly enhances the efficacy of other beta-lactam antibiotics.

Pharmacokinetics

Clavulanic acid is rapidly absorbed after oral administration, with peak plasma concentrations occurring within 1 hour. It is widely distributed throughout the body and has a half-life of approximately 1 hour. The drug is primarily excreted unchanged in the urine. In the presence of renal impairment, dosage adjustment may be necessary, as the elimination of clavulanic acid can be affected.

Contra-indications

• Hypersensitivity to clavulanic acid or any of the excipients
• History of jaundice or hepatic impairment associated with previous use of penicillins or beta-lactam antibiotics

Adverse effects

• Nausea
• Diarrhea
• Rash
• Elevated liver enzymes
• Allergic reactions including anaphylaxis
• Superinfection

Interactions

• May enhance the effects of anticoagulants such as warfarin
• Probenecid may increase plasma concentrations of clavulanic acid
• May reduce the efficacy of oral contraceptives

Precautions

• Caution in patients with renal impairment
• Monitor liver function in patients receiving prolonged therapy
• Use with caution in patients with a history of allergic reactions to beta-lactams

Pregnancy

Clavulanic acid is categorized as pregnancy category B. Animal studies have not shown any harm to the fetus, but there are no adequate and well-controlled studies in pregnant women.

Breast-feeding

Clavulanic acid is excreted in breast milk, but it is generally considered safe for use during breastfeeding. Monitor for potential effects in the infant.

Storage

Store at room temperature, away from moisture and heat. Protect from light. Keep out of reach of children.

Formulations

• Oral tablets
• Oral suspension
• Injectable forms