Benzayl Penicillin Sodium Mega (Each vial contains Benzayl Penicillin 600mg)

Indications

• Topical antiseptic for minor cuts and abrasions
• Local anesthetic for skin procedures
• Treatment of skin infections
• Preservative in pharmaceutical formulations

Dosage

Children: Refer to specific product guidelines for paediatric dosing as it can vary based on formulation and age.

Adults: Refer to specific product guidelines for dosing as it can vary based on formulation and intended use.

Mechanism of action

Benzyl compounds typically exert their effects by disrupting cellular membranes and inhibiting protein synthesis in bacteria. They can also block nerve conduction when used as anesthetics, providing localized pain relief.

Pharmacodynamics

In terms of pharmacodynamics, benzyl exhibits bacteriostatic and bactericidal properties against a range of Gram-positive and some Gram-negative bacteria. Its effectiveness as a local anesthetic is due to its ability to inhibit sodium channels, thereby preventing the initiation and transmission of nerve impulses.

Pharmacokinetics

Benzyl is generally well-absorbed through the skin when applied topically. Its metabolism primarily occurs in the liver, where it is converted to various metabolites. The elimination half-life can vary depending on the formulation and route of administration, but it is typically excreted through the urine.

Pregnancy

There are no adequate and well-controlled studies in pregnant women. The use of benzyl in pregnancy should be considered only if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

It is not known whether benzyl is excreted in human milk. Caution should be exercised when administering benzyl to a nursing mother.

Storage

Store at room temperature, away from direct sunlight and moisture. Keep out of reach of children.

Indications

• Bacterial infections
• Pneumonia
• Streptococcal infections
• Syphilis
• Meningitis
• Endocarditis
• Skin infections

Dosage

Children: Refer to the BNF for Children for specific dosing recommendations based on the type of penicillin and indication.

Adults: Refer to the BNF for specific dosing recommendations based on the type of penicillin and indication.

Mechanism of action

Penicillin targets penicillin-binding proteins (PBPs) located inside the bacterial cell wall. By binding to these proteins, penicillin disrupts the transpeptidation process, which is essential for cell wall structural integrity. This results in weakened cell walls, causing osmotic instability and ultimately leading to cell lysis and death.

Pharmacodynamics

Penicillin exhibits bactericidal activity, meaning that it kills bacteria rather than merely inhibiting their growth. Its effectiveness is generally dependent on the growth phase of the bacteria, as it is most active against actively dividing cells. The spectrum of activity varies among different penicillins, with some being more effective against specific bacterial strains.

Pharmacokinetics

Penicillin is primarily absorbed in the gastrointestinal tract, with its bioavailability varying depending on the specific type of penicillin. It is primarily excreted by the kidneys, with a half-life that typically ranges from 30 minutes to 2 hours, depending on the formulation. Dosage adjustments may be necessary in patients with renal impairment to prevent accumulation and toxicity.

Contra-indications

• History of hypersensitivity to penicillins
• Severe allergic reactions to beta-lactam antibiotics

Adverse effects

• Allergic reactions such as rash, urticaria, and anaphylaxis
• Gastrointestinal disturbances including nausea, vomiting, and diarrhea
• Superinfection due to alteration of normal flora
• Hematologic reactions such as leukopenia, thrombocytopenia

Interactions

• valproate+penicillins: Severe (increases risk of adverse effects)
• allopurinol+penicillins: Unknown (increases risk of skin rash)
• leflunomide+penicillins: Unknown (increases exposure)
• nitisinone+penicillins: Unknown (increases exposure)
• penicillins+phenindione: Unknown (increases risk of bleeding events)
• teriflunomide+penicillins: Unknown (increases exposure)

Precautions

• Use with caution in patients with renal impairment
• Monitor for signs of allergic reactions
• Consider alternative therapy in patients with a history of severe allergies

Pregnancy

Penicillins are generally considered safe to use during pregnancy; however, consult local guidelines and assess benefits versus risks.

Breast-feeding

Penicillins are excreted in breast milk in small amounts; generally considered safe, but monitor infant for possible effects.

Storage

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

Formulations

• Oral tablets
• Oral suspension
• Intravenous injection
• Intramuscular injection