2523 Dapsone A sulfone active against a wide range of bacteria but mainly employed for its actions against mycobacterium leprae. Its mechanism of action is probably similar to that of the sulfonamides which involves inhibition of folic acid synthesis in susceptible organisms. It is also used with pyrimethamine in the treatment of malaria. (From Martindale, The Extra Pharmacopoeia, 30th ed, p157-8) 80-08-0 2955 C12H12N2O2S 248.061950 White or creamy white crystalline powder (A619) 175.5°C 380 mg/L (at 37°C) Ingestion (L1039, T14); dermal (L1039, T14) ; eye contact (L1039, T14); inhalation (L1039, T14) Bioavailability is 70 to 80% following oral administration. Dapsone acts against bacteria and protozoa in the same way as sulphonamides, that is by inhibiting the synthesis of dihydrofolic acid through competition with para-amino-benzoate for the active site of dihydropteroate synthetase. The anti-inflammatory action of the drug is unrelated to its antibacterial action and is still not fully understood. Dapsone is slowly and nearly completely absporbed from GI tract, and distributed throughout the body. It is acetylated in the liver to monoacetyl and diacetyl derivatives. The major metabolite of dapsone is monoacetyldapsone. The rate of acetylation of dapsone is genetically determined and is subject to interindividual variation, although the rate is usually constant for each individual. The drug also is hydroxylated in the liver to hydroxylamine dapsone (NOH-DDS). NOH-DDS appears to be responsible for methemoglobinemia and hemolysis induced by the drug. The metabolites are excreted moslty in the urine. Only minor amounts of dapsone are excreted in feces. (A617, A618). Route of Elimination: Renal Half Life: 28 hours (range 10-50 hours) LD50: 496 mg/kg (Oral, Mouse) 3, not classifiable as to its carcinogenicity to humans. (L135) For the treatment and management of leprosy and dermatitis herpetiformis. Dapsone is mainly employed for its actions against mycobacterium leprae. It is also used with pyrimethamine in the treatment of malaria, and of Pneumocystis carinii pneumonia (PCP) (A308, L1039). Methemoglobinemia and hemolysis are the main risks of acute intoxication. Hemolytic anemia, agranulocytosis, aplastic anemia and other blood dyscrasias may occur in chronic poisoning. Target organs are central and peripheral nervous systems, blood, liver and skin. Methemoglobinemia is the principal and constant feature of dapsone poisoning. Hemolytic anaemia and agranulocytosis may occur with the relatively low doses used for leprosy and malaria, whereas peripheral neuropathy and hepatitis are only observed with the higher doses used in the treatment of dermatitis herpetiformis. (L1040). Overdosage might be expected to produce nasal congestion, syncope, or hallucinations. Measures to support blood pressure should be taken if necessary. Administer charcoal as a slurry following oral or parenteral exposure. (T36) 2009-07-03T22:07:24Z 2026-03-26T18:49:26Z Cytochrome P450 2E1 (CYP2E1) (P05181) Cytochrome P450 2C9 (CYP2C9) (P11712) (A308). Dapsone C07666 4325 Dapsone DB00250 377 true Cytochrome P450 2E1 (P05181) Cytochrome P450 2C9 (P11712) (A308) NC1=CC=C(C=C1)S(=O)(=O)C1=CC=C(N)C=C1 C12H12N2O2S InChI=1S/C12H12N2O2S/c13-9-1-5-11(6-2-9)17(15,16)12-7-3-10(14)4-8-12/h1-8H,13-14H2 MQJKPEGWNLWLTK-UHFFFAOYSA-N 248.301 248.061948328 Exogenous Solid 0.97 HMDB14395 CHEMBL1043 2849 <p>Weijiard, J.and Messerly, J.P.; U.S. Patent 2,385,899; October 2,1945; assigned to Merck<br /> &amp; Co., Inc.</p> CHEM002064 DTXSID4020371 NS00000683 4-(4-aminobenzenesulfonyl)aniline