GENTAFARM

Mechanism of action

Bisulfite functions primarily as a reducing agent in biochemical reactions. It can donate electrons, which is essential in various metabolic processes, including the degradation of cysteine and homocysteine. The compound is involved in pathways related to amino acid metabolism, specifically influencing sulfur amino acid metabolism, which is critical in maintaining cellular redox homeostasis.

Pharmacodynamics

The pharmacodynamic properties of bisulfite include its role in reducing oxidative stress by participating in redox reactions. It helps maintain the balance of thiol groups within proteins, which is vital for their structural integrity and function. Additionally, bisulfite may influence the activity of certain enzymes involved in the metabolism of amino acids.

Pharmacokinetics

Information on the pharmacokinetics of bisulfite is limited. However, it is known to be rapidly absorbed and metabolized in the body. Its primary metabolic pathways involve the degradation of sulfur-containing amino acids. Excretion typically occurs through urine, reflecting its metabolic products.

Pregnancy

Bisulfite is not recommended during pregnancy due to potential risks, consult healthcare professionals for alternatives.

Breast-feeding

Caution is advised when using bisulfite while breastfeeding, consult with healthcare professionals before use.

Storage

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

Indications

• Electrolyte replacement
• Volume expansion in hypovolemic patients
• Management of hyponatremia
• Support in intravenous fluid therapy

Dosage

Children: Refer to the BNF for Children for appropriate dosing in paediatric patients, as dosages may vary based on the formulation and clinical condition.

Adults: Refer to specific product information or clinical guidelines for dosage recommendations, as disodium is often part of combination products.

Mechanism of action

Disodium compounds often function by providing sodium ions that are essential for various physiological processes. Sodium ions play a critical role in maintaining osmotic balance, nerve impulse transmission, and muscle contraction. In the context of intravenous solutions, disodium helps to restore electrolyte balance in patients.

Pharmacodynamics

The pharmacodynamics of disodium is primarily related to its role in electrolyte balance and fluid homeostasis. Sodium ions are vital for the function of excitable tissues, including neurons and muscle cells. Changes in sodium levels can affect blood pressure, hydration status, and overall cellular function.

Pharmacokinetics

The pharmacokinetics of disodium compounds depend on their specific formulation and route of administration. When administered intravenously, disodium is rapidly distributed in the extracellular fluid, where it helps to maintain osmotic pressure. Sodium is primarily excreted by the kidneys, and its levels can be influenced by fluid intake, dietary sodium, and renal function.

Pregnancy

Use with caution. Consult a healthcare provider for specific guidance.

Breast-feeding

Use with caution. Consult a healthcare provider for specific guidance.

Storage

Store at room temperature, away from moisture and direct sunlight.

Indications

• Lead poisoning
• Mercury poisoning
• Calcium overload
• Certain diagnostic procedures involving heavy metals

Dosage

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

Adults: Refer to the BNF for specific dosing guidelines based on the condition being treated, considering factors such as the severity of metal poisoning and renal function.

Mechanism of action

Edetate functions by forming stable complexes with divalent and trivalent metal ions, including lead and calcium, through its multiple carboxylate and amine groups. This chelation renders the metals more soluble and promotes their renal excretion, thereby reducing their toxic effects in the body.

Pharmacodynamics

The chelation of metals by edetate decreases the free metal concentration in the bloodstream, which mitigates the toxic effects associated with heavy metal accumulation. The efficacy of edetate in removing metals such as lead has been well documented, and its ability to bind calcium can influence calcium homeostasis in certain clinical scenarios.

Pharmacokinetics

Edetate is administered intravenously, with rapid distribution throughout the extracellular fluid. It is primarily excreted unchanged by the kidneys. The onset of action occurs quickly after administration, and the duration depends on the dose and the patient's renal function. The elimination half-life is approximately 1 hour but may vary based on renal clearance.

Contra-indications

• Hypersensitivity to edetate or any component of the formulation
• Severe renal impairment
• Active bleeding disorders

Adverse effects

• Hypocalcemia
• Nausea
• Vomiting
• Diarrhea
• Abdominal pain
• Headache
• Rash
• Fever

Interactions

• May enhance the effects of anticoagulants
• Concurrent use with calcium supplements may reduce effectiveness
• May interfere with the absorption of certain medications due to changes in gastrointestinal motility

Precautions

• Use with caution in patients with renal impairment
• Monitor electrolyte levels, particularly calcium, during treatment
• Assess the patient's hydration status before administration

Pregnancy

Limited data on the use of edetate in pregnancy. Use only if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

Caution is advised as it is not known whether edetate is excreted in human milk. Weigh the risks and benefits before use.

Storage

Store in a cool, dry place, protected from light. Do not freeze.

Formulations

• Edetate disodium injection
• Edetate calcium disodium injection

Indications

• Severe infections caused by Gram-negative bacteria
• Urinary tract infections
• Bacteremia
• Sepsis
• Pneumonia
• Intra-abdominal infections
• Skin and soft tissue infections

Dosage

Adults: The usual dosage for adults is 3 to 5 mg/kg/day divided into 3 doses, given intravenously or intramuscularly. Adjustments should be made based on renal function and severity of infection.

Mechanism of action

Gentamicin acts by binding to the bacterial 30S ribosomal subunit, leading to misreading of mRNA and subsequent production of nonfunctional or toxic peptides. This disrupts protein synthesis and leads to bacterial cell death. The drug enters bacterial cells in a three-phase process: first, ionic binding occurs with the cell membrane, increasing permeability. Second, energy-dependent transport allows the drug to access its intracellular target. Third, concentration-dependent killing is observed as gentamicin accumulates within the cell, amplifying its effects on protein synthesis and membrane integrity.

Pharmacodynamics

Gentamicin exhibits concentration-dependent bactericidal activity, meaning that its efficacy increases with higher concentrations. The pharmacodynamic properties highlight the rapid and delayed bactericidal effects, with membrane disruption occurring immediately followed by impaired protein synthesis. The drug's action is particularly effective against aerobic Gram-negative bacteria, while its effectiveness is significantly reduced in anaerobic conditions.

Pharmacokinetics

Gentamicin is poorly absorbed from the gastrointestinal tract; thus, it is typically administered intravenously or intramuscularly. It has a volume of distribution that reflects extensive tissue penetration, particularly in renal and gastrointestinal tissues. The elimination half-life ranges from 2 to 3 hours in healthy individuals, but it can be prolonged in patients with renal impairment. The drug is primarily eliminated by renal excretion, with dosage adjustments required in cases of renal dysfunction.

Contra-indications

• Hypersensitivity to gentamicin or other aminoglycosides
• Severe renal impairment
• Myasthenia gravis

Adverse effects

• Nephrotoxicity
• Ototoxicity (hearing loss, balance disorders)
• Neuromuscular blockade
• Allergic reactions (rash, pruritus)
• Peripheral neuropathy

Interactions

• Increased risk of nephrotoxicity with other nephrotoxic agents (e.g., cisplatin, vancomycin)
• Increased risk of ototoxicity with loop diuretics (e.g., furosemide)
• Synergistic effects with beta-lactam antibiotics

Precautions

• Monitor renal function during treatment
• Use caution in patients with pre-existing hearing loss
• Adjust dosage in patients with renal impairment
• Consider potential drug interactions

Pregnancy

Gentamicin should be used during pregnancy only if clearly needed, due to potential risk of fetal harm.

Breast-feeding

Gentamicin is excreted in breast milk, but is generally considered safe. Monitor for possible effects on the infant.

Storage

Store in a cool, dry place, away from light. Do not refrigerate or freeze.

Formulations

• Injection (solution for injection)
• Topical ointment
• Eye drops

Mechanism of action

There are 3 key phases of aminoglycoside entry into cells. The first “ionic binding phase” occurs when polycationic aminoglycosides bind electrostatically to negatively charged components of bacterial cell membranes including with lipopolysaccharides and phospholipids within the outer membrane of Gram-negative bacteria and to teichoic acids and phospholipids within the cell membrane of Gram-positive bacteria. This binding results in displacement of divalent cations and increased membrane permeability, allowing for aminoglycoside entry. The second “energy-dependent phase I” of aminoglycoside entry into the cytoplasm relies on the proton-motive force and allows a limited amount of aminoglycoside access to its primary intracellular target - the bacterial 30S ribosome. This ultimately results in the mistranslation of proteins and disruption of the cytoplasmic membrane. Finally, in the “energy-dependent phase II” stage, concentration-dependent bacterial killing is observed. Aminoglycoside rapidly accumulates in the cell due to the damaged cytoplasmic membrane, and protein mistranslation and synthesis inhibition is amplified. The necessity of oxygen-dependent active transport explains why aminoglycosides are ineffective against anaerobic bacteria. Hence, aminoglycosides have both immediate bactericidal effects through membrane disruption and delayed bactericidal effects through impaired protein synthesis; observed experimental data and mathematical modeling support this two-mechanism model. Inhibition of protein synthesis is a key component of aminoglycoside efficacy. Structural and cell biological studies suggest that aminoglycosides bind to the 16S rRNA in helix 44 (h44), near the A site of the 30S ribosomal subunit, altering interactions between h44 and h45. This binding also displaces two important residues, A1492 and A1493, from h44, mimicking normal conformational changes that occur with successful codon-anticodon pairing in the A site. Overall, aminoglycoside binding has several negative effects including inhibition of translation, initiation, elongation, and ribosome recycling. Recent evidence suggests that the latter effect is due to a cryptic second binding site situated in h69 of the 23S rRNA of the 50S ribosomal subunit. Also, by stabilizing a conformation that mimics correct codon-anticodon pairing, aminoglycosides promote error-prone translation. Mistranslated proteins can incorporate into the cell membrane, inducing the damage discussed above. 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/ ... 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/