Sulfonamide allergy toxicity

Furosemide Loop diuretic Decreases NaCI and KCI reabsorption in thick ascending limb of the loop of Henle in the nephron (see Chapter 15) Increased excretion of salt and water reduces cardiac preload and afterload reduces pulmonary and peripheral edema Acute and chronic heart failure severe hypertension edematous conditions Oral and IV duration 2-4 h Toxicity Hypovolemia, hypokalemia, orthostatic hypotension, ototoxicity, sulfonamide allergy... 

Hydrochlorothiazide Decreases NaCI reabsorption in the distal convoluted tubule Same as furosemide, but less efficacious Mild chronic failure mild-moderate hypertension hypercalciuria Oral only duration 10-12 h Toxicity Hyponatremia, hypokalemia, hyperglycemia, hyperuricemia, hyperlipidemia, sulfonamide allergy... 

Toxicity Loop diuretics usually induce hypokalemic metabolic alkalosis. Because large amounts of sodium are presented to the collecting tubules, wasting of potassium (which is excreted by the kidney in an effort to conserve sodium) may be severe. Because they are so efficacious, the loop diuretics can cause hypovolemia and cardiovascular complications. Ototoxicity is an important toxic effect of the loop agents. The sulfonamides in this group may cause typical sulfonamide allergy. 

Metolazone, though not a thiazide, is a sulfonamide that is often used as a thiazide substitute. Metolazone s site of action, effects, and toxicities (including sulfonamide allergy) are indistinguishable from the true thiazides. The answer is (G). 

Adverse effects associated with ocular drugs are not imcommon, bnt serious reactions are extremely rare. These adverse reactions are nsnally manifestations of drug hypersensitivity (allergy) or toxicity. The allergic or toxic reaction usually occurs locally in the ocular tissues. Occasionally, as in erythema multiforme potentiated by sulfonamide agents, adverse reactions can manifest as a systemic response. 

Other toxic effects of NSAIDs include hypersensitivity reactions, rash, and central nervous system complaints of drowsiness, dizziness, headaches, depression, confusion, and tinnitus. Although NSAIDs are generally avoided in patients with asthma who are aspirin-intolerant, studies indicate that celecoxib and rofecoxib are well tolerated in aspirin-sensitive asthma, providing a viable option for these patients. Celecoxib and valdecoxib are sulfonamides and are thus contraindicated for those with sulfa allergies. 

CAIs should be used with caution in patients with sulfa allergies (all CAIs, topical or systemic, contain sulfonamide moieties), sicklecell disease, respiratory acidosis, pulmonary disorders, renal calculi, electrolyte imbalance, hepatic disease, renal disease, diabetes melli-tus, or Addison s disease. Concurrent use of a CAI and a diuretic may rapidly produce hypokalemia. High-dose salicylate therapy may increase the acidosis produced by CAIs, whereas the acidosis produced by CAIs may increase the toxicity of salicylates. 

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