(3) Hyperuricemia. Thiazides may reduce uric acid excretion and simultaneously reduce blood volume, which concentrates uric acid in the blood. This may predispose a hyperuricemic patient to gout. Contact physician if significant sudden joint pain occurs. If pt is on probenecid, an anti gout med, thiazide may decrease the effectiveness of it. (4) Hyperglycemia. Hyperglycemia is of concern for type 2 diabetic or prediabetic patients. It is believed the hypokalemia produced by thiazides may decrease release of insulin from the pancreas . This isn’t a problem with type 1 because they have no insulin. Blood glucose levels should be evaluated regularly and frequently, especially during early treatment. The effect of thiazides on potassium is dose-dependent and may be less of a problem with the 12.5 mg HCTZ dose. Some clinicians suggest the choice of treatment of hypertension in type 2 diabetics is a combination of low-dose thiazide plus an ACE inhibitor. (5). Oliguria. High doses of thiazides, particularly in elderly subjects or patients with impaired renal function, can reduce GFR and renal blood flow. The drug is contraindicated in oliguria. Monitor urine output and BUN levels. If urine output falls, notify the physician. A sudden onset of confusion or altered consciousness may indicate azotemia. If they kidneys arent working, thiazides wont work. (6). Thiazides should not be given to pregnant or breast-feeding women. The drug is potentially dangerous in pregnancy. Thrombocytopenia and hemolytic anemia have rarely been reported in newborns; jaundice also may occur in the newborn. The thiazides are listed as Pregnancy Category B or C but are considered "inappropriate" in 13
Cardiovascular pregnancy. There are some studies that show that they may cause some fetal changes…so you should not use during pregnancy. (7) Thiazides may unexpectedly aggravate borderline renal or hepatic insufficiency in elderly patients. They may increase serum levels of LDL and may cause erectile dysfunction. e. Interactions: (1). Hypotensive drugs: Additive effect (often beneficial). (2). Lithium: Risk of lithium toxicity because the natriuretic effect of diuretics results in increased lithium tubular reabsorption and blood level. Concurrent use should be avoided if possible; otherwise monitor the patient closely for signs and symptoms of lithium toxicity and reduce the dose of lithium as necessary. Lithium has a narrow therapeutic index. Its elimination and reabsorption is related to sodium. If you have a pt. on lithium, you tell them “don’t change your salt diet”..dont go on a low salt diet, don’t start eating salt. If you have a pt in lithium and they have HTN and you need to put them on a thiazide diuretic, you need to change the dose of the lithium. You can cause lithium toxicity if you either give a low salt diet or a salt losing diuretic like the thiazides and the loop diuretics.
- Summer '16