NEBAGIN POWDER

Indications

• Topical treatment of superficial skin infections
• Prevention of infections in minor cuts and abrasions
• Conditions caused by susceptible gram-positive bacteria

Dosage

Children: For children, dosing is similar to adults, but refer to BNF for Children for specific recommendations and guidelines.

Adults: For topical application, bacitracin ointment should be applied 1 to 3 times daily to the affected area. Refer to specific guidelines for dosage details.

Mechanism of action

Bacitracin binds to divalent metal ions such as Mn(II), Co(II), Ni(II), Cu(II), or Zn(II). These complexes subsequently bind C55-isoprenyl pyrophosphate, which inhibits the hydrolysis of lipid dolichol pyrophosphate, ultimately blocking cell wall synthesis. Bacitracin also interferes with the incorporation of amino acids and nucleotides into the bacterial cell wall, damages the bacterial plasma membrane, and can oxidatively cleave DNA.

Pharmacodynamics

Bacitracin's pharmacodynamics involve its ability to inhibit bacterial cell wall synthesis and oxidative DNA cleavage. The drug has a short duration of action, necessitating frequent topical applications every 3 to 4 hours. While effective against a range of gram-positive bacteria, the risk of nephrotoxicity when given intramuscularly limits its systemic use.

Pharmacokinetics

Bacitracin is poorly absorbed from the gastrointestinal tract and is primarily administered topically. Systemic absorption can occur if given intramuscularly, leading to potential nephrotoxicity. The drug has a short half-life and requires frequent dosing to maintain effective concentrations at the site of infection.

Adverse effects

• Nephrotoxicity (when given intramuscularly)
• Allergic reactions
• Dermatitis
• Local irritation at the application site

Precautions

• Use with caution in patients with renal impairment
• Avoid intramuscular use due to risk of nephrotoxicity
• Monitor for allergic reactions in patients with a history of hypersensitivity to antibiotics

Pregnancy

Bacitracin should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Limited data are available regarding its safety in pregnancy.

Breast-feeding

Bacitracin is expected to be excreted in breast milk, caution should be exercised when administering to nursing mothers.

Storage

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

Formulations

• Topical ointment
• Topical powder

Indications

• Topical treatment of localized skin infections
• Ophthalmic infections
• Ear infections
• Bacterial conjunctivitis

Dosage

Children: Refer to the BNF for Children for specific dosing information.

Adults: For topical use, apply a thin layer to the affected area 1 to 3 times daily or as directed by a healthcare professional.

Mechanism of action

Gramicidin exerts its antibacterial effect by disrupting the bacterial cell membrane. It forms channels in the membrane, leading to increased permeability and subsequent loss of essential intracellular components, which ultimately results in cell death. This mechanism is particularly effective against gram-positive bacteria.

Pharmacodynamics

The pharmacodynamics of gramicidin involves its interaction with the bacterial cell membrane, causing leakage of ions and small molecules, which is detrimental to bacterial survival. The drug's potency is influenced by its concentration and the susceptibility of the bacteria involved. Gramicidin shows bactericidal activity, meaning it kills bacteria rather than merely inhibiting their growth.

Pharmacokinetics

Gramicidin is primarily administered topically, and its systemic absorption is minimal, which limits its use to localized infections. Due to its polypeptide structure, it is not well absorbed through the gastrointestinal tract. The elimination half-life of gramicidin is not well defined due to its topical use and limited systemic exposure. Localized application ensures high concentrations at the site of infection with minimal side effects.

Adverse effects

• Local irritation
• Allergic reactions

Precautions

• Use with caution in patients with a history of hypersensitivity to gramicidin or other antibiotics
• Should not be used in large areas of the body or on broken skin

Pregnancy

Gramicidin is not recommended during pregnancy unless clearly needed.

Breast-feeding

It is not known whether gramicidin is excreted in human milk. Caution should be exercised when administering to nursing mothers.

Storage

Store in a cool, dry place away from light.

Formulations

• Topical solution
• Ointment
• Eye drops

Indications

• Severe bacterial infections
• Intra-abdominal infections
• Sepsis
• Urinary tract infections
• Pneumonia
• Bone and joint infections

Dosage

Children: Refer to the BNF for Children for appropriate dosing based on the child’s age and weight.

Adults: Refer to specific clinical guidelines or the BNF for appropriate dosing based on the type and severity of infection.

Mechanism of action

Neogracin exerts its antibacterial effects by binding to the 30S ribosomal subunit of susceptible bacteria. This binding interferes with the initiation complex of protein synthesis and causes misreading of mRNA, leading to the production of nonfunctional or toxic peptides. This disruption in protein synthesis is critical for bacterial growth and replication, resulting in bactericidal activity.

Pharmacodynamics

The pharmacodynamics of neogracin involve its ability to exert concentration-dependent bactericidal activity. Higher concentrations of the drug result in increased bacterial killing. The drug's efficacy is influenced by the duration of exposure and the ability to achieve sufficient concentrations in the site of infection. Neogracin is typically more effective against aerobic gram-negative bacteria, including Pseudomonas aeruginosa and Escherichia coli.

Pharmacokinetics

Neogracin is administered parenterally, as it is poorly absorbed from the gastrointestinal tract. After intravenous administration, it distributes widely in body tissues and fluids, with a volume of distribution that suggests good penetration into extracellular fluid. The drug is primarily eliminated via renal excretion; therefore, dose adjustments are often necessary in patients with renal impairment. The half-life of neogracin may vary based on individual patient factors but generally ranges from 2 to 3 hours in healthy adults.

Pregnancy

Neogracin is generally not recommended during pregnancy due to potential risks to the fetus. Consult healthcare professionals for risk assessment.

Breast-feeding

Neogracin may be excreted in human milk; caution is advised when administering to breastfeeding mothers.

Storage

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

Mechanism of action

Bacitracin binds to a divalent metal ion such as Mn(II), Co(II), Ni(II), Cu(II), or Zn(II). These complexes bind C₅₅-isoprenyl pyrophosphate, preventing the hydrolysis of a lipid dolichol pyrophosphate, which finally inhibits cell wall synthesis. Bacitracin metal complexes also bind and oxidatively cleave DNA. Bacitracin interferes with bacterial cell wall synthesis by blocking the function of the lipid carrier molecule that transfers cell wall subunits across the cell membrane. It is active against many gram positive bacteria including staphylococci, streptococci (particularly group A streptococci), corynebacteria, and clostridia. It is also active against Actinomyces, Treponema pallidum and some gram negative species such as Neisseria and Haemophilus influenzae, although most Gram-negative organisms are resistant. . Bacitracin may be bactericidal or bacteriostatic in action, depending on the concentration of the drug attained at the site of infection and the susceptibility of the infecting organism. Bacitracin inhibits bacterial cell wall synthesis by preventing the incorporation of amino acids and nucleotides into the cell wall. The drug probably interferes with the final dephosphorylation step in the phospholipid carrier cycle and in this manner bacitracin prevents the transfer of the mucopeptide to the growing cell wall. Bacitracin also damages the bacterial plasma membrane and is active against protoplasts. Bacitracin is a polypeptide antibiotic active against Gram-positive bacterial strains. Its mechanism of action postulates disturbing the cell wall synthesis by inhibiting dephosphorylation of the lipid carrier. We have discovered that bacitracin induces degradation of nucleic acids, being particularly active against RNA. In the examination of the nucleolytic activity of bacitracin several model RNA and DNA oligomers were used. The oligomers were labeled at their 5' ends with (32)P radioisotope and following treatment with bacitracin the cleavage sites and efficiency were determined. Bacitracin induces degradation of RNA at guanosine residues, preferentially in single-stranded RNA regions. Bacitracin is also able to degrade DNA to some extent but comparable effects to those observed with RNA require its 10-fold higher concentration. The sites of degradation in DNA are very infrequent and preferentially occur near cytidine residues. Free radicals are not involved in the reaction, and which probably proceeds via a hydrolytic mechanism. The phosphate groups at the cleavage sites are present at the 3' ends of RNA products and at the 5' ends of DNA fragments. Importantly, the presence of EDTA does not influence RNA degradation but completely inhibits the degradation of DNA. For DNA degradation divalent metal ions like Mg(2+), Mn(2+) or Zn(2+) are absolutely necessary. The ability of bacitracin to degrade nucleic acids via a hydrolytic mechanism was a surprising observation, and it is of interest whether these properties can contribute to its mechanisms of action during antibiotic treatment.

Pharmacodynamics

Bacitracin is a mixture of polypeptides that prevent the formation of the bacterial cell wall and oxidatively cleave DNA. It has a short duration of action as it must be given every 3 to 4 hours topically. Bacitracin is nephrotoxic when given intramuscularly and may lead to renal failure.