PHENOXYMETHYLPENICILLIN 250MG TABLET

Indications

• Bacterial respiratory tract infections
• Skin and soft tissue infections
• Streptococcal infections
• Meningitis caused by susceptible organisms
• Bone and joint infections

Dosage

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

Adults: Refer to the specific guidelines in the BNF for details on dosage regimens for adults.

Mechanism of action

Henoxymethylpenicillin works by inhibiting bacterial cell wall synthesis. It binds to penicillin-binding proteins (PBPs) located inside the bacterial cell wall, disrupting the cross-linking of peptidoglycan layers, which are essential for maintaining cell wall structural integrity. This leads to cell lysis and ultimately, bacterial death.

Pharmacodynamics

Henoxymethylpenicillin exhibits time-dependent bactericidal activity, meaning that its efficacy is related to the duration of time the drug concentration remains above the minimum inhibitory concentration (MIC) for the target bacteria. It has a broad spectrum of activity against various gram-positive and some gram-negative organisms, making it a versatile antibiotic for treating infections.

Pharmacokinetics

Henoxymethylpenicillin is absorbed well orally, although food can affect its bioavailability. It is widely distributed throughout body tissues and fluids, including the lungs, kidneys, and even the central nervous system in therapeutic concentrations. The drug is primarily eliminated by the kidneys through glomerular filtration and tubular secretion, resulting in a relatively short half-life, necessitating multiple daily doses for effective treatment.

Contra-indications

• Hypersensitivity to penicillin or any component of the formulation
• History of severe allergic reactions to beta-lactam antibiotics

Adverse effects

• Allergic reactions, including anaphylaxis
• Rash
• Nausea
• Diarrhea
• Hepatic dysfunction
• Nephrotoxicity

Interactions

• Probenecid may increase the serum levels of penicillin
• Concurrent use with other nephrotoxic drugs may increase the risk of renal impairment

Precautions

• Use with caution in patients with a history of asthma or allergic conditions
• Monitor for signs of superinfection during prolonged therapy
• Adjust dose in renal impairment

Pregnancy

Generally considered safe in pregnancy; however, use only if clearly needed and after assessing risk versus benefit.

Breast-feeding

Penicillin is excreted in breast milk in small amounts; it is usually considered safe during breastfeeding.

Storage

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

Formulations

• Oral tablets
• Oral suspension
• Injectable forms