Erdostin

Approved Indications:

• Chronic Obstructive Pulmonary Disease (COPD): As a mucolytic agent to reduce the frequency and severity of acute exacerbations.
• Chronic Bronchitis: For the treatment of increased mucus secretion and to improve sputum clearance.
• Acute Respiratory Tract Infections: Adjunct therapy to facilitate mucus clearance and symptom relief in conditions such as acute bronchitis, pharyngitis, and sinusitis.

Clinically Accepted Off-label Uses:

• Cystic Fibrosis: Occasionally used as an adjunct mucolytic to improve airway clearance.
• Asthma (non-allergic bronchial hyperreactivity): In selected patients, to aid mucus removal when hypersecretion is significant.

Adults:

• Standard Dose: 300 mg twice daily (600 mg/day), orally.
• Duration: Typically for 5–10 days in acute conditions, or longer (up to several months) in chronic cases, as per physician’s discretion.

Pediatric Use:

• Children aged 2–12 years: 10 mg/kg/day, divided into two doses.
• Children >12 years: Adult dosing may be applied.

Elderly:

• No dose adjustment is generally required unless renal or hepatic impairment is present.

Renal Impairment:

• Moderate to Severe Renal Impairment (CrCl <30 mL/min): Use with caution; dose reduction may be necessary. Monitor renal function and adjust dosing accordingly.

Hepatic Impairment:

• Caution is advised. Although no specific dose adjustment is recommended, close clinical monitoring is necessary.

Route of Administration:

• Oral (available as capsules, tablets, or granules for suspension).

Administration Notes:

• Can be taken with or without food.
• Maintain hydration to enhance mucolytic action.

Erdosteine is a prodrug that is metabolized in the liver to its active metabolite, met-I, which contains free thiol groups. These thiol groups cleave disulfide bonds in the mucoprotein structure of mucus, reducing its viscosity and improving clearance from the respiratory tract. Erdosteine also exhibits antioxidant and anti-inflammatory properties by scavenging free radicals and modulating cytokine production. This contributes to reduced oxidative stress in the airways, beneficial especially in chronic respiratory diseases such as COPD.

• Absorption: Rapidly absorbed from the gastrointestinal tract after oral administration.
• Bioavailability: Approximately 64–80% after first-pass metabolism.
• Onset of Action: Within 1–2 hours after administration.
• Distribution: Widely distributed; plasma protein binding approximately 64%.
• Metabolism: Hepatically metabolized to active metabolite Met-I.
• Half-Life: Around 1.5–3 hours for the parent compound; longer for active metabolites.
• Excretion: Primarily via the urine (as metabolites); minor elimination through feces.
• Steady-State: Achieved within 2–3 days of twice-daily dosing.

• Pregnancy: Erdosteine is classified as Pregnancy Category B (non-FDA classification). Animal studies do not indicate direct or indirect harmful effects with respect to reproductive toxicity. However, controlled studies in pregnant women are lacking. Use only if clearly needed.
• Lactation: It is unknown whether Erdosteine or its metabolites are excreted in human milk. A risk to the infant cannot be excluded. Caution is advised if administered during breastfeeding.

• Primary Class: Mucolytic Agent
• Subclass: Thiol derivative mucolytic with antioxidant properties

• Known hypersensitivity to Erdosteine or any of its excipients
• Active peptic ulcer
• Severe hepatic insufficiency
• Severe renal impairment without dose adjustment
• Children under 2 years of age (in some formulations)

• Hepatic or Renal Impairment: Use with caution; dose adjustment or close monitoring may be necessary.
• Gastrointestinal Disorders: Not recommended in patients with active gastric or duodenal ulcer.
• Asthmatic Patients: May cause bronchospasm in sensitive individuals.
• Mucolytic Overuse: May lead to increased liquefaction of bronchial secretions and risk of aspiration if cough reflex is impaired.
• Liver Enzymes Monitoring: Advised in prolonged use.
• Cough Reflex Suppression: Avoid combining with antitussives in conditions where cough is protective.

Common Side Effects (≥1%):

• Gastrointestinal:
• Nausea
• Vomiting
• Abdominal pain
• Diarrhea
• Central Nervous System:
• Headache
• Dizziness
• Respiratory:
• Cough or throat irritation

Uncommon to Rare Side Effects:

• Skin: Rash, pruritus, urticaria
• Liver: Elevated transaminases (ALT/AST)
• Hypersensitivity Reactions: Angioedema, anaphylactoid reactions (very rare)
• Others: Metallic taste, fatigue

• Antitussives (e.g., codeine): Avoid co-administration due to risk of mucus accumulation from suppressed cough reflex.
• Antibiotics (e.g., amoxicillin, cefuroxime): No clinically significant interaction; may enhance mucolytic antibiotic delivery.
• Theophylline: No known interactions.
• Food: Does not significantly affect absorption or efficacy.
• Enzyme Systems: Erdosteine does not significantly affect or depend on CYP450 metabolism for clinical activity, hence low risk of metabolic interactions.

• Recent COPD Guidelines (GOLD 2023): Erdosteine is recognized as a supportive agent to reduce exacerbations in moderate-to-severe COPD.
• Post-marketing Surveillance: No major safety alerts or black box warnings have been issued.
• Expanded Use: Growing interest in its antioxidant role in inflammatory lung diseases; however, not yet guideline-endorsed for conditions beyond COPD and chronic bronchitis.

• Temperature: Store below 25°C (77°F).
• Humidity: Protect from excessive moisture.
• Light: Store in a well-closed container away from direct sunlight.
• Handling Precautions: No special handling required.
• Oral Suspension (if applicable): Once reconstituted, use within 7–10 days and store in a refrigerator (2–8°C); shake well before use.