Lithium toxicity induced by combined amiloride HCl-hydrochlorothiazide administration

A Review of Critical Differences among Loop, Thiazide, and Thiazide-Like Diuretics

Diuretics are a drug class with heterogeneous assortments. This article reviews general pharmacologic mechanisms and clinical implications of loop, thiazide, and thiazide-like diuretics.

Loop diuretics act in the loop of Henle by blocking the sodium-potassium-chloride (Na+-K+-2Cl-) symport. They are effective in relieving congestive symptoms and edematous signs of heart failure. Activation of the neurohormonal system and subsequent pathologic myocardial remodeling limit the use of loop diuretics unless fluid balance is not met to relieve patients' symptoms with life-saving pharmacologic modalities. Adverse effects on electrolyte balance may cause life-threatening consequences. The combination of K+-sparing diuretics or angiotensin-converting enzyme inhibitors with loop diuretics may not only prevent life-threatening complications caused by electrolyte imbalance, but also may delay progression of the disease with proven mortality benefit. Recent findings of worsening renal function and higher mortality rate with the use of oral and intravenous loop diuretics further demands appropriate use of these drugs.

Thiazide diuretics and thiazide-like diuretics act in the distal convoluted tubule by blocking Na+-Cl- symport. Thiazide diuretics reduce cardiovascular mortality by achieving target blood pressure in patients with hypertension. Compared with other antihypertensive drugs, thiazide diuretics have less desirable metabolic effects. However, it has not yet been shown that the negative metabolic effects of these drugs are associated with negative mortality and morbidity. Based on the need for a multidrug regimen to reach target blood pressure in most patients with hypertension, thiazide diuretics may be used in addition to a drug or drugs without metabolic complications.

Drug-drug interactions in pediatric psychopharmacology

Serious consequences caused by drug-drug interactions continue to plague contemporary pharmacotherapy. The possibility of a drug-drug interaction should be suspected anytime a new or unexpected effect occurs that complicates the clinical management of a patient in the setting where the patient is receiving more than one drug. In this article, the authors address the mechanisms of pharmacokinetic-based drug-drug interactions focusing on important interactions that may occur with the common medications a pediatrician may prescribe to the child receiving psychoactive medication(s) prescribed by a child psychiatrist.

Lithium toxicity and myxedema coma in an elderly woman

The development of hypothyroidism as a side effect of lithium therapy is a well recognized phenomenon. However, the presentation of myxedema coma after lithium intoxication has not been previously documented. In this case lithium toxicity may have exacerbated preexisting hypothyroidism to the point of respiratory arrest. Based on this case, we recommend periodic monitoring of thyroid function in an effort to detect preexisting hypothyroidism or lithium-induced hypothyroidism.