Sulphonylbisbenzamine – Indications, Contraindication

Autoimmune disease

• Cutaneous lupus erythematosus. Dapsone is effective and safe in persons with moderate, severe, or refractory cutaneous lupus erythematosus.^[rx]
• Idiopathic thrombocytopenic purpura. Dapsone is effective and safe for adjunctive glucocorticoid-sparing treatment of persons with idiopathic thrombocytopenic purpura and is preferred over danazol or interferon-alpha in those people with antinuclear antibodies.^[rx]
• Chronic spontaneous urticaria. Dapsone is effective and safe for the treatment of second-line therapy for people with chronic spontaneous urticaria in those for whom antihistamines and other first-line agents have failed.^[rx][rx]
• Relapsing polychondritis. There are no clinical trials but there are many cases reports that dapsone is effective at doses of 25 mg/day to 200 mg/day for treatment of relapsing polychondritis.

Contraindications of Dapsone Gel

• glucose-6-phosphate dehydrogenase (G6PD) deficiency
• deficiency of the blood enzyme cytochrome b5 reductase
• significant anemia
• liver problems
• Anemia from Pyruvate Kinase and G6PD Deficiencies
• Absolute contraindications to the use of dapsone are prior hypersensitivity to dapsone or its derivatives including agranulocytosis and hypersensitivity syndrome. Deaths from agranulocytosis, aplastic anemia, and other blood dyscrasias have been reported with dapsone administration.
• Relative contraindications to the use of dapsone include allergy to sulfonamide antibiotics, significant cardiopulmonary disease, significant liver or renal function impairment, or pre-existing peripheral neuropathy.
• For the treatment of women who are pregnant, dapsone is a category C drug. Therefore, it should be used with caution only if benefits outweigh risks.
• According to the American Academy of Pediatrics, dapsone is listed as a “maternal medication usually compatible with breastfeeding.”
• Allergies to Sulfone

Dosage of sulphonylbisbenzamine

Strengths: 100 mg; 25 mg

Leprosy – Lepromatous

• 50 to 100 mg orally once a day for 2-5 years.

Leprosy – Tuberculoid

• 100 mg orally once a day for 6 months. Rifampin is additionally recommended to reduce the incidence of dapsone resistance. If the disease relapses, this regimen should be repeated.

Dermatitis Herpetiformis

• 50 mg orally once a day continued on a life-long basis. Dosage may be advanced to 300 mg/day. Dosage reduction to a minimum maintenance level as soon as possible is recommended.

Pneumocystis Pneumonia

• 100 mg orally once a day for 14 to 21 days. Used in combination with trimethoprim.

Pneumocystis Pneumonia Prophylaxis

• 100 mg orally twice a week. Therapy should be continued on a life-long basis. The addition of pyrimethamine appears to significantly increase the activity of dapsone for PCP prophylaxis.

Toxoplasmosis – Prophylaxis

• 100 mg orally twice a week continued on a life-long basis.

Pediatric Dose for Leprosy

• 1 to 2 mg/kg (up to 100 mg) orally once a day.

Pediatric Dose for Pneumocystis Pneumonia Prophylaxis

1 month

• 2 mg/kg/day (up to 100 mg) orally once a day.

Alternate dosing > 1 month

• 4 mg/kg orally once weekly. Maximum dose = 200 mg.

Pediatric Dose for Toxoplasmosis

> 1 month

• g2 mg/kg/day (or 15 mg/m2) orally once a day.
• Maximum dose = 25 mg. Dapsone should be administered as part of combination therapy for prophylaxis of toxoplasmosis.

Side Effects of sulphonylbisbenzamine

More common

• easy bruising
• itching, dryness, redness, scaling, or peeling of the skin
• loss of hair
• numbing or tingling sensation in the hands or feet
• signs of depression (e.g., poor concentration, changes in weight, changes in sleep, decreased interest in activities)
• signs of infections (e.g., fever or chills, sore throat)
• signs of liver problems (e.g., nausea, vomiting, diarrhea, loss of appetite, weight loss, yellowing of the skin or whites of the eyes, dark urine, pale stools)
• unusual tiredness or weakness
• Back, leg, or stomach pains
• bluish fingernails, lips, or skin
• difficult breathing
• fever
• loss of appetite
• pale skin
• skin rash
• unusual tiredness or weakness

Common

• Hematologic: Hemolytic anemia, methemoglobinemia, leukopenia, and agranulocytosis
• Cutaneous hypersensitivity reactions: Mebilliform eruption, exfoliative erythroderma, drug-induced lupus erythematosus, and toxic epidermal necrolysis
• Neurologic: Peripheral neuropathy, predominantly motor loss
• Psychiatric: Psychosis and insomnia
• Eyes: Blurred vision
• Ear, nose, and throat: Tinnitus and vertigo
• Cardiac: Tachycardia
• Pulmonary: Pulmonary Eosinophilia
• Hepatic: Hepatitis, dapsone syndrome, cholestatic jaundice, and hypoalbuminemia without proteinuria
• Gastrointestinal: Nausea, vomiting, abdominal pain, anorexia, and pancreatitis
• Renal: Nephrotic syndrome, albuminur
• signs of anemia (low red blood cells; e.g., dizziness, pale skin, unusual tiredness or weakness, shortness of breath)
• signs of infection (fever, severe chills, sore throat, mouth ulcers)
• signs of an allergic reaction (e.g., rash, hives, swelling of the lips or face, difficulty breathing)

Rare

• severe vomiting
• signs of methemoglobinemia (e.g., headache, fatigue, dizziness, shortness of breath, grey or bluish skin colour, especially of lips, mouth and nail beds)
• signs of pancreatitis (e.g., abdominal pain on the upper left side, back pain, nausea, fever, chills, rapid heartbeat, swollen abdomen)
• Itching, dryness, redness, scaling, or peeling of the skin, or loss of hair
• mood or other mental changes
• numbness, tingling, pain, burning, or weakness in hands or feet
• sore throat
• unusual bleeding or bruising
• yellow eyes or skin
• blurred vision
• dizziness
• fast heartbeat
• fatigue
• headache
• loss of appetite
• nausea or vomiting
• skin rash or itch
• trouble sleeping

Drug Interactions of sulphonylbisbenzamine

• azole antifungals (e.g., fluconazole, itraconazole, ketoconazole, voriconazole)
• anti-malarial medications (e.g., chloroquine, hydroxychloroquine, primaquine)
• benzoyl peroxide
• celecoxib
• flutamide
• nitrates (e.g., isosorbide dinitrate, isosorbide mononitrate, nitroglycerin)
• lidocaine
• metoclopramide
• phenazopyridine
• phenobarbital
• chloroquine
• clarithromycin
• didanosine
• hydroxychloroquine
• mefloquine
• nicardipine
• probenecid
• proguanil
• protease inhibitors; anti-HIV medications (lopinavir, ritonavir, saquinavir)
• St. John’s wort
• sodium nitrite
• sulfadiazine
• sulfamethoxazole
• sulfasalazine
• tetracaine
• trimethoprim
• sulfisoxazole

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

Pregnancy Category of sulphonylbisbenzamine

Pregnancy

This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding

This medication passes into breast milk. If you are a breast-feeding mother and are taking dapsone, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding. This medication should not be used for children less than 1-month-old. The safety and effectiveness of using this medication have not been established for children less than 12 years old.

References