AMOFLUX 500 CAPSULES

Indications

• Bacterial infections
• Urinary tract infections
• Sinusitis
• Uncomplicated community-acquired pneumonia
• Salmonellosis
• Oral infections
• Lyme disease (under expert supervision)
• Acute exacerbation of bronchiectasis
• Anthrax (treatment and post-exposure prophylaxis)

Dosage

Children: 1 month–11 years: 30 mg/kg 3 times a day for 21 days; children 1–4 years: 250 mg 3 times a day; children 5–11 years: 500 mg 3 times a day.

Adults: 500 mg 3 times a day; increased if necessary up to 1 g 3 times a day in severe infections.

Mechanism of action

Amoxicillin works by inhibiting bacterial cell wall synthesis, leading to cell lysis and death. It binds to penicillin-binding proteins (PBPs) located inside the bacterial cell wall, interfering with the transpeptidation process necessary for cell wall integrity.

Pharmacodynamics

Amoxicillin exhibits bactericidal activity against susceptible bacteria. Its action is time-dependent, meaning that its effectiveness is related to the duration of time that the drug concentration remains above the minimum inhibitory concentration (MIC) for the target pathogen.

Pharmacokinetics

Amoxicillin is well absorbed from the gastrointestinal tract, with peak plasma concentrations achieved within 1-2 hours after oral administration. It is widely distributed in body tissues and fluids, and it is excreted primarily via the kidneys. The elimination half-life is approximately 1 hour, and renal impairment may necessitate dosage adjustments.

Adverse effects

• Skin rash
• Gastrointestinal disturbances (nausea, vomiting, diarrhea)
• Allergic reactions (including anaphylaxis)
• Superinfection (due to resistant organisms)

Interactions

• Allopurinol (increases risk of skin rash)

Precautions

• History of penicillin allergy
• Renal impairment (reduce dose)
• Use with caution in patients with mononucleosis

Pregnancy

Use only if clearly needed; no adequate studies in pregnant women.

Breast-feeding

Amoxicillin is excreted in breast milk; use with caution.

Storage

Store in a cool, dry place away from direct sunlight.

Formulations

• Phenoxymethylpenicillin 250mg/5ml oral solution
• Phenoxymethylpenicillin 250 mg tablets

Indications

• Skin and soft tissue infections
• Respiratory tract infections
• Bone and joint infections
• Endocarditis prophylaxis
• Osteomyelitis

Dosage

Children: Refer to the BNF for Children for appropriate dosing guidelines based on age and weight.

Adults: Refer to the BNF for specific dosing information, as it may vary depending on the type and severity of the infection.

Mechanism of action

Flucoxicillin works by inhibiting bacterial cell wall synthesis. It binds to penicillin-binding proteins (PBPs) located inside the bacterial cell wall, preventing the cross-linking of peptidoglycan layers. This action weakens the cell wall, leading to cell lysis and ultimately bacterial death. Its resistance to beta-lactamase enzymes allows it to maintain its antibacterial activity against certain resistant strains.

Pharmacodynamics

Flucoxicillin exhibits bactericidal activity, meaning it kills bacteria rather than merely inhibiting their growth. The minimum inhibitory concentration (MIC) for susceptible strains is typically low, indicating that effective concentrations can be achieved easily. The drug is particularly effective against Staphylococcus aureus, including methicillin-sensitive strains.

Pharmacokinetics

Flucoxicillin is absorbed well from the gastrointestinal tract, with peak plasma concentrations occurring approximately 1-2 hours after oral administration. It is widely distributed throughout body tissues and fluids, including bone, where it achieves therapeutic concentrations. The drug is primarily excreted by the kidneys, with around 60-70% of the administered dose eliminated unchanged in the urine. The half-life is approximately 1 hour, necessitating multiple doses throughout the day for sustained efficacy.

Contra-indications

• Hypersensitivity to flucloxacillin or any other penicillin antibiotic
• History of severe allergic reactions to beta-lactam antibiotics

Adverse effects

• Nausea
• Vomiting
• Diarrhea
• Abdominal pain
• Rash
• Urticaria
• Anaphylaxis
• Hepatotoxicity
• Nephrotoxicity

Interactions

• Probenecid may increase the serum concentrations of flucloxacillin
• Anticoagulants may have altered effects due to antibiotic-induced changes in gut flora

Precautions

• Use with caution in patients with a history of liver dysfunction
• Monitor renal function in patients receiving high doses or prolonged therapy
• Assess for potential drug interactions with other medications

Pregnancy

Flucloxacillin is generally considered safe to use during pregnancy when indicated, as no evidence of teratogenic effects has been reported.

Breast-feeding

Flucloxacillin is excreted in breast milk in small amounts, and is usually considered safe for use during breastfeeding.

Storage

Store below 25 degrees Celsius, protect from light, and keep out of reach of children.

Formulations

• Capsules
• Oral solution
• Injection (intravenous or intramuscular)

Mechanism of action

Amoxicillin competitively inhibits penicillin-binding protein 1 and other high molecular weight penicillin binding proteins. Penicillin bind proteins are responsible for glycosyltransferase and transpeptidase reactions that lead to cross-linking of D-alanine and D-aspartic acid in bacterial cell walls. Without the action of penicillin binding proteins, bacteria upregulate autolytic enzymes and are unable to build and repair the cell wall, leading to bacteriocidal action. The penicillins and their metabolites are potent immunogens because of their ability to combine with proteins and act as haptens for acute antibody-mediated reactions. The most frequent (about 95 percent) or "major" determinant of penicillin allergy is the penicilloyl determinant produced by opening the beta-lactam ring of the penicillin. This allows linkage of the penicillin to protein at the amide group. "Minor" determinants (less frequent) are the other metabolites formed, including native penicillin and penicilloic acids. /Penicillins/ Amoxicillin is similar to penicillin in its bactericidal action against susceptible bacteria during the stage of active multiplication. It acts through the inhibition of cell wall biosynthesis that leads to the death of the bacteria.

Pharmacodynamics

Amoxicillin competitively inhibit penicillin binding proteins, leading to upregulation of autolytic enzymes and inhibition of cell wall synthesis. Amoxicillin has a long duration of action as it is usually given twice daily. Amoxicillin has a wide therapeutic range as mild overdoses are not associated with significant toxicity. Patients should be counselled regarding the risk of anaphylaxis, _Clostridium difficile_ infections, and bacterial resistance.