SULFABIOTIC COMBINATION PRODUCT DUSTING POWDER

Indications

• Bowel sterilization before surgery
• Hepatic coma
• Topical infections caused by susceptible organisms

Dosage

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

Adults: By mouth: 1 g every 1 hour for 4 hours, then 1 g every 4 hours for 2–3 days. For hepatic coma: Up to 4 g daily in divided doses usually for 5–7 days.

Mechanism of action

Neomycin sulfate binds to the 30S ribosomal subunit of bacteria, leading to the misreading of mRNA and the inhibition of protein synthesis. This disrupts the production of essential proteins needed for bacterial growth and function, ultimately resulting in cell death.

Pharmacodynamics

Neomycin demonstrates bactericidal activity against susceptible bacteria. Its efficacy is enhanced in alkaline environments, which is why it is often used in combination with other agents for surgical prophylaxis. The drug is primarily effective against a range of gram-negative organisms, including Escherichia coli and Klebsiella species, but also has some activity against gram-positive organisms.

Pharmacokinetics

Neomycin is poorly absorbed from the gastrointestinal tract, and its systemic absorption is minimal when administered orally. In cases of systemic use, such as intramuscular or intravenous administration, neomycin is distributed widely in the body but is primarily excreted unchanged in the urine. The elimination half-life varies but is generally around 2 to 3 hours in individuals with normal renal function. Monitoring of serum concentrations is essential to prevent toxicity, especially in patients with renal impairment.

Adverse effects

• neurotoxicity
• ototoxicity
• nephrotoxicity
• allergic reactions
• skin rashes
• hearing loss

Interactions

• other nephrotoxic drugs
• loop diuretics
• neuromuscular blocking agents

Precautions

• monitor renal function
• use cautiously in patients with hearing impairment
• avoid concurrent use with other ototoxic medications
• ensure adequate hydration

Pregnancy

Safety in pregnancy has not been established. Use only if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

Use caution; neomycin can be absorbed systemically and may affect the nursing infant.

Storage

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

Formulations

• oral tablets
• topical ointments
• injectable solutions

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

• Bacterial infections caused by aerobic organisms
• Topical treatment of skin infections

Mechanism of action

Neomycin binds to specific proteins and 16S rRNA within the 30S ribosomal subunit of susceptible bacteria. This binding interferes with the decoding site, causing misreading of mRNA and leading to the incorporation of incorrect amino acids into polypeptides. As a result, nonfunctional or toxic peptides are produced, and polysomes are disrupted into nonfunctional monosomes. Neomycin's bactericidal action is characterized by its ability to irreversibly bind to the 30S ribosomal subunit, thereby inhibiting bacterial protein synthesis.

Pharmacodynamics

Neomycin is primarily active against aerobic bacteria and is not effective against fungi, viruses, or most anaerobic bacteria. It mediates its bactericidal effects by inhibiting protein synthesis, which suppresses bacterial growth and survival. Following oral administration, neomycin exhibits a duration of bactericidal activity lasting between 48 to 72 hours. It is particularly useful in treating infections caused by strains of E. coli and Klebsiella, and it also acts to reduce colonic bacterial populations in patients with hepatic coma.

Pharmacokinetics

Neomycin is poorly absorbed from the gastrointestinal tract when taken orally, which limits its systemic availability and enhances its utility in targeting colonic bacteria. It is generally not used parenterally due to its potential for nephrotoxicity and ototoxicity. The duration of action following oral administration can last from 48 to 72 hours, and it is primarily excreted unchanged in the urine. Caution should be exercised when using neomycin in patients with renal impairment, as the risk of toxicity increases.

Adverse effects

• Nephrotoxicity
• Ototoxicity
• Allergic reactions
• Diarrhea
• Nausea
• Vomiting

Interactions

• neomycin+digoxin: Unknown (decreases absorption)
• neomycin+sorafenib: Unknown (decreases exposure)

Precautions

• Use with caution in patients with renal impairment
• Monitor renal function during therapy
• Evaluate hearing function in long-term use

Pregnancy

Neomycin is classified as category D; it should be used only if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

Neomycin is excreted in breast milk; caution should be exercised when administered to nursing mothers.

Storage

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

Formulations

• Topical ointment
• Cream
• Eye drops
• Oral tablets

Indications

• Bacterial conjunctivitis
• Blepharitis
• Skin infections due to susceptible organisms
• Secondary infections in skin conditions

Dosage

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

Adults: Refer to the BNF for specific dosing information.

Mechanism of action

Sulfacetamide acts as a competitive inhibitor of para-aminobenzoic acid (PABA), which is essential for bacterial growth. By inhibiting this reaction, sulfacetamide disrupts the synthesis of folic acid, a critical component for bacterial proliferation.

Pharmacodynamics

Sulfacetamide displays bacteriostatic activity, meaning it inhibits the growth and reproduction of bacteria rather than killing them outright. Its effectiveness varies, and resistance may develop, which is common among sulfonamides. When used, sulfacetamide achieves significant concentrations in various body fluids, including synovial, peritoneal, and ocular fluids, although its antibacterial efficacy may be reduced in the presence of pus.

Pharmacokinetics

Sulfacetamide is well absorbed when administered orally, although parenteral forms are challenging due to their alkaline nature, which can cause tissue irritation. The drug is widely distributed throughout body tissues, achieving high concentrations in fluids that are critical for treating infections. While it is not typically used for meningitis, it can reach high levels in the cerebrospinal fluid during meningeal infections.

Contra-indications

• Hypersensitivity to sulfonamides or any component of the formulation
• Severe liver or kidney impairment
• History of blood dyscrasias associated with sulfonamides

Adverse effects

• Nausea
• Vomiting
• Diarrhea
• Rash
• Itching
• Hematologic reactions (e.g., agranulocytosis, aplastic anemia)
• Hypersensitivity reactions
• Dizziness
• Headache

Interactions

• May enhance the effects of anticoagulants
• May diminish the effectiveness of oral hypoglycemics
• Interactions with methenamine, which may cause crystalluria
• May increase the risk of toxicity with drugs that cause bone marrow suppression

Precautions

• Use with caution in patients with glucose-6-phosphate dehydrogenase deficiency
• Monitor for signs of hematologic toxicity
• Hydrate adequately to prevent crystalluria
• Discontinue at the first sign of a rash or hypersensitivity reaction

Pregnancy

Sulfacetamide should be used in pregnancy only if the potential benefit justifies the potential risk to the fetus. It is classified as Category C.

Breast-feeding

Sulfacetamide is excreted in breast milk. Caution should be exercised when administering to nursing mothers.

Storage

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

Formulations

• Topical cream
• Topical lotion
• Ophthalmic solution

Mechanism of action

Framycetin binds to specific 30S-subunit proteins and 16S rRNA, four nucleotides of 16S rRNA and a single amino acid of protein S12. This interferes with decoding site in the vicinity of nucleotide 1400 in 16S rRNA of 30S subunit. This region interacts with the wobble base in the anticodon of tRNA. This leads to interference with the initiation complex, misreading of mRNA so incorrect amino acids are inserted into the polypeptide leading to nonfunctional or toxic peptides and the breakup of polysomes into nonfunctional monosomes. Like other aminoglycoside antibiotic drugs, neomycin inhibits bacterial ribosomes by binding to the 30S ribosomal subunit of susceptible bacteria and disrupting the translational machinery of bacterial protein synthesis. Bacterial translation is normally initiated by the mRNA binding to the 30S ribosomal subunit and subsequent binding with 50S subunit for elongation. Aminoglycosides are usually bactericidal in action. Although the exact mechanism of action has not been fully elucidated, the drugs appear to inhibit protein synthesis in susceptible bacteria by irreversibly binding to 30S ribosomal subunits. /Aminoglycosides/ A class of angiogenesis inhibitor has emerged from our mechanistic study of the action of angiogenin, a potent angiogenic factor. Neomycin, an aminoglycoside antibiotic, inhibits nuclear translocation of human angiogenin in human endothelial cells, an essential step for angiogenin-induced angiogenesis. The phospholipase C-inhibiting activity of neomycin appears to be involved, because U-73122, another phospholipase C inhibitor, has a similar effect. In contrast, genistein, oxophenylarsine, and staurosporine, inhibitors of tyrosine kinase, phosphotyrosine phosphatase, and protein kinase C, respectively, do not inhibit nuclear translocation of angiogenin. Neomycin inhibits angiogenin-induced proliferation of human endothelial cells in a dose-dependent manner. At 50 microM, neomycin abolishes angiogenin-induced proliferation but does not affect the basal level of proliferation and cell viability. Other aminoglycoside antibiotics, including gentamicin, streptomycin, kanamycin, amikacin, and paromomycin, have no effect on angiogenin-induced cell proliferation. Most importantly, neomycin completely inhibits angiogenin-induced angiogenesis in the chicken chorioallantoic membrane at a dose as low as 20 ng per egg. These results suggest that neomycin and its analogs are a class of agents that may be developed for anti-angiogenin therapy. ... Aminoglycosides are aminocyclitols that kill bacteria by inhibiting protein synthesis as they bind to the 16S rRNA and by disrupting the integrity of bacterial cell membrane. Aminoglycoside resistance mechanisms include: (a) the deactivation of aminoglycosides by N-acetylation, adenylylation or O-phosphorylation, (b) the reduction of the intracellular concentration of aminoglycosides by changes in outer membrane permeability, decreased inner membrane transport, active efflux, and drug trapping, (c) the alteration of the 30S ribosomal subunit target by mutation, and (d) methylation of the aminoglycoside binding site. ... /Aminoglycosides/

Pharmacodynamics

Framycetin is used for the treatment of bacterial eye infections such as conjunctivitis. Framycetin is an antibiotic. It is not active against fungi, viruses and most kinds of anaerobic bacteria. Framycetin works by binding to the bacterial 30S ribosomal subunit, causing misreading of t-RNA, leaving the bacterium unable to synthesize proteins vital to its growth. Framycetin is useful primarily in infections involving aerobic bacteria bacteria. Neomycin mediates its bactericidal action by inhibiting bacterial protein synthesis, thereby suppressing the growth and survival of susceptible bacteria. Following oral administration, the duration of bactericidal activity of neomycin ranged from 48 to 72 hours. By decreasing colonic bacteria that produce ammonia, neomycin was shown to be effective as an adjunctive therapy in hepatic coma to improve neurologic symptoms. Neomycin is active against both gram positive and gram negative organisms, including the major _E. coli_ species resident in the colon as well as the enteropathogenic forms of _E. coli_. It is also active against _Klebsiella_-_Enterobacter_ group. Resistant strains of _E. coli_, _Klebsiella_ and _Proteus spp_. may emerge from neomycin therapy. Neomycin has no antifungal activity and has some activity against some protozoa.

Mechanism of action

Sulfacetamide is a competitive inhibitor of bacterial para-aminobenzoic acid (PABA), an essential component for bacterial growth (according to the Woods-Fildes theory). The inhibited reaction is necessary in these organisms for the synthesis of folic acid.

Pharmacodynamics

Sulfacetamide is a sulfonamide antibiotic with bacteriostatic actions and broad-spectrum activity against most gram-positive and many gram-negative organisms. However, many strains of an individual species may be resistant. Sulfonamides inhibit multiplication of bacteria by acting as competitive inhibitors of <i>p</i>-aminobenzoic acid in the folic acid metabolism cycle. Bacterial sensitivity is the same for the various sulfonamides, and resistance to one sulfonamide indicates resistance to all. Most sulfonamides are readily absorbed orally. However, parenteral administration is difficult, since the soluble sulfonamide salts are highly alkaline and irritating to the tissues. The sulfonamides are widely distributed throughout all tissues. High levels are achieved in pleural, peritoneal, synovial, and ocular fluids. Although these drugs are no longer used to treat meningitis, CSF levels are high in meningeal infections. Their antibacterial action is inhibited by pus.