Dapclin

Approved Indications:

• Leprosy:
• Part of multidrug therapy (MDT) for all forms of Hansen’s disease (leprosy).
• Dermatitis Herpetiformis:
• Used to control symptoms such as itching and rash.
• Pneumocystis jirovecii Pneumonia (PCP) Prophylaxis:
• In patients intolerant to trimethoprim-sulfamethoxazole (TMP-SMX).

Clinically Accepted Off-label Uses:

• Autoimmune blistering diseases: Such as bullous systemic lupus erythematosus.
• Other dermatologic disorders: Including linear IgA bullous dermatosis, and certain neutrophilic dermatoses.
• Malaria: In combination regimens for prophylaxis or treatment (less common).
• Toxoplasmosis: As alternative therapy in prophylaxis or treatment.

Adults:

• Leprosy:
• 50–100 mg orally once daily or divided doses weekly as part of MDT.
• Dermatitis Herpetiformis:
• Initial dose: 50 mg orally daily, titrate up to 100–200 mg daily based on response.
• PCP Prophylaxis:
• 100 mg orally once daily.

Pediatrics:

• Dose based on weight, typically 1–2 mg/kg/day divided doses.

Elderly:

• Use with caution; monitor closely for adverse effects.

Renal/Hepatic Impairment:

• Use with caution; no specific dose adjustment but monitor closely for toxicity.

Administration:

• Oral tablets with or without food.

Dapsone is a synthetic sulfone antibiotic with anti-inflammatory properties. It acts primarily by inhibiting bacterial synthesis of dihydrofolic acid through competitive antagonism of para-aminobenzoic acid (PABA) in susceptible organisms, impairing folate metabolism and thus bacterial growth. Additionally, dapsone exerts immunomodulatory effects by inhibiting neutrophil myeloperoxidase and suppressing neutrophil-mediated inflammatory responses, which contributes to its efficacy in inflammatory dermatoses.

Absorption:

• Well absorbed orally, peak plasma concentrations reached 2 to 8 hours post-dose.
• Bioavailability approximately 70-80%.

Distribution:

• Widely distributed; high affinity for skin and liver.
• Plasma protein binding approximately 70–90%.

Metabolism:

• Metabolized primarily in the liver via acetylation and hydroxylation to active and inactive metabolites.

Elimination:

• Excreted in urine mainly as metabolites; small amounts excreted unchanged.
• Half-life approximately 20 to 30 hours; may be prolonged in renal impairment.

• Pregnancy:
• FDA Category C. Use only if potential benefits justify risks; animal studies show adverse effects.
• Lactation:
• Excreted in breast milk; caution advised. Monitor infant for adverse reactions.

• Primary Class: Antibacterial agent
• Subclass: Sulfone antibiotic; anti-inflammatory agent

• Known hypersensitivity to dapsone or sulfones.
• Severe anemia or G6PD deficiency (due to risk of hemolysis).
• Severe hepatic or renal impairment without close monitoring.

• Hemolytic Anemia: Risk especially in G6PD-deficient patients; monitor CBC regularly.
• Methemoglobinemia: Monitor for cyanosis, hypoxia; more frequent in high doses.
• Hypersensitivity Reactions: Potential for severe reactions including Dapsone Hypersensitivity Syndrome (fever, rash, hepatitis).
• Peripheral Neuropathy: May occur with prolonged use.
• Liver Function: Monitor in patients with hepatic impairment.
• Blood Dyscrasias: Regular hematologic monitoring recommended.

Common:

• Hemolysis (dose-related)
• Methemoglobinemia
• Rash and pruritus
• Gastrointestinal upset (nausea, anorexia)
• Headache

Serious/Rare:

• Dapsone Hypersensitivity Syndrome (rash, fever, lymphadenopathy, hepatitis)
• Agranulocytosis
• Peripheral neuropathy
• Hepatitis and jaundice
• Severe anemia requiring transfusion

• Rifampin: May reduce dapsone plasma levels via hepatic enzyme induction.
• Cimetidine: May increase dapsone levels by inhibiting metabolism.
• Antiepileptics (phenytoin, carbamazepine): Possible reduction in efficacy due to induction.
• Other Hemolytic Agents: Increased risk of hemolysis when combined.

• WHO continues to recommend dapsone as a key component of multidrug therapy for leprosy.
• Updated monitoring guidelines emphasize early detection of hypersensitivity syndrome and hemolytic anemia.
• Increased awareness and recommendations for G6PD deficiency screening before initiation.

• Store at 20°C to 25°C (68°F to 77°F).
• Protect from moisture and light.
• Keep tablets in tightly closed container.
• Keep out of reach of children.