Dapsone

INTRODUCTION

Indications

Treatment of leprosy (in combination with other agents). Treatment of dermatitis herpetiformis. Treatment of acne vulgaris (topical). Unlabeled Use: Prevention (as monotherapy) and treatment of Pneumocystis carinii pneumonia (with trimethoprim or other agents).

Action

Interferes with folate synthesis in susceptible organisms. Therapeutic Effects: Bacteriostatic action. Spectrum: Active against Mycobacterium leprae, Pneumocystis carinii.

Adverse Reactions/Side Effects

CNS: headache, insomnia, mood changes, tonic-clonic movements (topical), vertigo. EENT: blurred vision, tinnitus, pharyngitis (topical). GI: HEPATOTOXICITY, abdominal pain, nausea, pancreatitis, vomiting. Derm: exfoliative dermatitis, hypersensitivity reactions, including erythema nodosum leprosum, photosensitivity, Stevens-Johnson syndrome, systemic lupus erythematosus. Hemat: AGRANULOCYTOSIS, METHEMOGLOBINEMIA, hemolytic anemia, reticulocytosis. Neuro: peripheral neuropathy.

PHYSICAL THERAPY IMPLICATIONS

Examination and Evaluation

• Be alert for signs of liver toxicity, including anorexia, abdominal pain, severe nausea and vomiting, yellow skin or eyes, fever, sore throat, malaise, weakness, facial edema, lethargy, and unusual bleeding or bruising. Report these signs to the physician immediately.

• Monitor signs of agranulocytosis (fever, sore throat, mucosal lesions, signs of infection), methemoglobinemia (bluish coloring of skin, headache, shortness of breath, lack of energy), or other unusual weakness and fatigue that might be due to other anemias and blood dyscrasias. Report these signs to the physician immediately.

• Monitor signs of hypersensitivity reactions, including skin reactions (rash, hives, itching) and Stevens-Johnson syndrome (severe dermatitis and exfoliation). Notify physician immediately because these signs may indicate serious hypersensitivity reactions.

• Monitor signs of peripheral neuropathy (numbness, tingling). Perform objective tests (nerve conduction, monofilaments) to document any neuropathic changes.

• Determine if vertigo or abnormal movements affects gait and balance and if patient is at an increased risk of falls (See Appendices C, E).

Interventions

• Always wash hands thoroughly and disinfect equipment (whirlpools, electrotherapeutic devices, treatment tables, and so forth) to help prevent the spread of infection. Use universal precautions or isolation procedures as indicated for specific patients.

• Causes photosensitivity; use care if administering UV treatments.

Patient/Client-Related Instruction

• Advise patient about photosensitivity, and to use sunscreens, protective clothing, and avoid prolonged sun exposure. Advise patient to also report any rashes or other skin reactions.

• Advise patient about the likelihood of GI reactions such as nausea, vomiting, and abdominal pain. Instruct patient to report severe or prolonged GI problems or signs of pancreatitis (upper abdominal pain after eating, indigestion, weight loss, oily stools).

• Instruct patient and family/caregivers to report other troublesome side effects such as severe or prolonged headache, sleep loss, mood changes, blurred vision, ringing/buzzing in the ears (tinnitus), or throat irritation.

Pharmacokinetics

Absorption: Slowly absorbed (70–80%) following oral administration; acidic environment promotes absorption.