WBR0413

Author	[[PageAuthor::Rim Halaby, M.D. [1]]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Pharmacology
Sub Category	SubCategory::Renal
Prompt	[[Prompt::A 72 year old male patient presents to your office with dyspnea and bilateral pitting edema. His past medical history is significant for diabetes mellitus, gout, and osteoarthritis. Upon further questioning, the patient tells you he cannot tolerate several medications because he is allergic. Among the list of medications that he has tried in the past, he recalls he developed skin rash when he used sulfonylurea, probenicid, celecoxib, and sulfonamide antibiotics. Nonetheless, you decide to prescribe him a diuretic to relieve his symptoms. Which of the following diuretics is the best option for this patient?]]
Answer A	AnswerA::Furosemide
Answer A Explanation	[[AnswerAExp::Furosemide is a loop diuretic that commonly causes sulfa allergy.]]
Answer B	AnswerB::Acetazolamide
Answer B Explanation	[[AnswerBExp::Acetazolamide is carbonic anhydrase inhibitor that commonly causes sulfa allergy.]]
Answer C	AnswerC::Ethacrynic acid
Answer C Explanation	[[AnswerCExp::Ethacrynic acid is a helpful diuretic in patients with sulfa allergy.]]
Answer D	AnswerD::Hydrochlorothiazide
Answer D Explanation	[[AnswerDExp::Hydrochlorothiazide is a thiazides-type diuretic. All thiazides are associated with sulfa allergy.]]
Answer E	AnswerE::Chlorthalidone
Answer E Explanation	AnswerEExp::Chlorthalidone is also a thiazides-type diuretic. All thiazides are associated with sulfa allergy.
Right Answer	RightAnswer::C
Explanation	[[Explanation::Sulfa allergy is a term that describes adverse drug reactions to a list of several medications. Sulfa allergy is typically seen in the following medications: Sulfonamide, sulfasalazine, sulfonylurea, celecoxib, probenicid, and diuretics such as furosemide, acetazolamide, and thiazides-type diuretics. Sulfa allergy has an incidence rate of less than 5% among the general population. It has a range of manifestations from very mild to fatal. Symptoms include skin rash, hepatic, renal, and pulmonary injury, and hematologic disturbances, such as thrombocytopenia, leucopenia, and hemolytic anemia. Treatment of sulfa allergy includes stopping the offending medications and symptomatic treatment of its manifestations until resolution. In patients who require dieresis, ethacrynic acid, a phenoxyacetic acid derivative, is a loop diuretic that is not associated with sulfa allergy. Because it is frequently associated with ototoxicity, it is usually only reserved for patients who are known to have sulfa allergy. Educational Objective: Ethacrynic acid is a helpful diuretic in patients with sulfa allergy. Sulfa allergy is a range of skin, visceral, and hematological manifestations that occur following intake of some medications. Sulfa allergy symptoms might range from very mild to very severe. Reference: Wall GC, Bigner D, Craig S. Ethacrynic acid and the sulfa-sensitive patient. Arch Intern Med. 2003;163(1):116-117. Educational Objective: References: ]]
Approved	Approved::No
Keyword	WBRKeyword::Sulfa drug allergy, WBRKeyword::diuretics, WBRKeyword::ethacrynic acid
Linked Question	Linked::
Order in Linked Questions	LinkedOrder::