Which of the following statements is not true regarding sulfonamides -

Ans. is 'a' i.e., Sulfasalazine is absorbed well from GIT o Sulfasalazine is poorly absorbed from the gastrointestinal tract. Sulfasalazine is a compound of sulfapyridine and 5 - aminosalicylicacid. Only 10-20% of orally administered sulfasalazine is absorbed. o It is split up in the intestine to release sulfapyridine and 5 - ASA. Sulfapyridine is well absorbed while 5 - amino salicylic acid remains unabsorbed. Sulfonamides can precipitate in urine specially at neutral or acid pH producing crystalluria, hematuria or even obstruction. Crystalluria is treated by administration of sodium bicarbonate to alkalinize the urine and fluids to maintain adequate hydration. Crystalluria is minimum with soluble drugs like sulfisoxazole. o Kernicterus may be precipitated in new born specially if premature by displacement of bilirubin from plasma protein bending sites and more permeable blood brain barrier. Sulfonamides are primarily bacteriostatic. They inhibit both gram positive and gram negative bacteria, nocardia, chlamydia trachomatis and some protozoa. o Sulfadoxine is longest acting whereas sulfacystine is shoest acting.