MAXITROL EYE DROPS

Indications

• Ophthalmic inflammatory conditions
• Bacterial conjunctivitis
• Inflammatory skin conditions with secondary bacterial infection
• Ear infections with inflammatory components

Dosage

Children: Dosing for paediatric patients should be determined based on age, weight, and clinical circumstances. Refer to

Adults: Dosing for adult patients should be guided by clinical judgment and specific product information. Refer to established guidelines or product packaging for specific dosing recommendations.

Mechanism of action

Dexamethasone exerts its effects by binding to the glucocorticoid receptor, leading to the modulation of gene expression that results in anti-inflammatory and immunosuppressive actions. It inhibits the production of inflammatory mediators such as prostaglandins and leukotrienes. Polymyxin B acts by disrupting the bacterial cell membrane, leading to cell death, particularly in gram-negative bacteria. It binds to the lipid A portion of lipopolysaccharides in the bacterial cell membrane, compromising the integrity of the membrane.

Pharmacodynamics

The pharmacodynamic profile of dexamethasone-polymyxin indicates a synergistic effect where dexamethasone reduces inflammation and immune response, while polymyxin B combats bacterial infections. This dual action can be beneficial in treating conditions characterized by both inflammation and infection, such as bacterial conjunctivitis with significant inflammatory response.

Pharmacokinetics

Dexamethasone is well absorbed from the gastrointestinal tract if administered orally, with a bioavailability of around 70%. It has a large volume of distribution and is highly protein-bound. The elimination half-life varies but averages around 3 to 4 hours. Polymyxin B has a different pharmacokinetic profile, with poor oral absorption; it is typically administered parenterally or topically. It has a short half-life and is primarily eliminated by the kidneys. The pharmacokinetics of the combination may vary based on the route of administration.

Contra-indications

• Systemic fungal infections
• Hypersensitivity to dexamethasone, polymyxin B, or any of the components of the formulation

Adverse effects

• Immunosuppression
• Gastrointestinal disturbances such as nausea and vomiting
• Mood changes including euphoria or depression
• Fluid retention and electrolyte imbalances
• Increased risk of infections
• Local irritation or allergic reactions at the site of administration

Interactions

• Increased risk of toxicity when used with other immunosuppressants
• Potential interaction with anticoagulants, which may alter their effectiveness
• Caution with live vaccines due to immunosuppressive effects

Precautions

• Use with caution in patients with pre-existing infections
• Monitor for signs of adrenal insufficiency during prolonged therapy
• Careful consideration in patients with diabetes, hypertension, or peptic ulcer disease

Pregnancy

Dexamethasone is classified as category C. Use during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

Dexamethasone is excreted in breast milk. Use caution and consider risks versus benefits when prescribing to nursing mothers.

Storage

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

Formulations

• Topical ointment containing dexamethasone and polymyxin B
• Eye drops containing dexamethasone and polymyxin B

Indications

• Bacterial infections
• Respiratory tract infections
• Urinary tract infections
• Sepsis

Dosage

Children: Refer to specific guidelines or protocols for dosing based on the infection type and severity; dosing may vary.

Adults: Refer to specific guidelines or protocols for dosing based on the infection type and severity; dosing may vary.

Mechanism of action

Sulphateneomycin works by binding to the 30S ribosomal subunit of bacteria, inhibiting protein synthesis. This binding disrupts the translation process, leading to the production of nonfunctional or toxic peptides, ultimately resulting in bacterial cell death.

Pharmacodynamics

The pharmacodynamic profile of sulphateneomycin is characterized by its concentration-dependent bactericidal activity. The effect of the drug is influenced by the peak serum concentration achieved relative to the minimum inhibitory concentration (MIC) of the target bacteria. Higher peak concentrations generally correlate with increased efficacy against susceptible organisms.

Pharmacokinetics

Sulphateneomycin is generally administered via parenteral routes due to poor oral absorption. Following administration, it distributes widely in body tissues but shows a preference for renal excretion. Its half-life can vary based on the patient's renal function, with adjustments often necessary in cases of renal impairment. Due to its mechanism of action, bacterial resistance can develop, making careful consideration of susceptibility testing important.

Contra-indications

• Hypersensitivity to sulfonamides
• Severe liver disease
• Blood dyscrasias

Adverse effects

• Nausea
• Vomiting
• Diarrhea
• Rash
• Hematological reactions
• Liver toxicity
• Renal impairment

Interactions

• May potentiate the effects of anticoagulants
• May interact with methotrexate leading to increased toxicity
• May decrease the effectiveness of oral contraceptives

Precautions

• Use with caution in patients with renal impairment
• Monitor liver function tests in patients on prolonged therapy
• Assess for signs of hypersensitivity reactions

Pregnancy

Category C. Sulphonamides should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

Sulphonamides are excreted in breast milk; caution is advised when administering to nursing mothers.

Storage

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

Formulations

• Tablets
• Injectable solution