Occasionally loop diuretics cause elevated blood sugar in diabetics . They can elevate cholesterol and triglycerides, although the long-term clinical significance of this effect is uncertain. Multiple other side effects and drug interactions are possible with these drugs. All of the loop diuretics except ethacrynic acid are sulfonamides and can infrequently cause sulfa allergies. It is possible that people with an allergy to sulfa antibiotics such as sulfamethoxazole or sulfisoxazole will have cross-sensitivity to these diuretics.
Thiazides are also available in combination with other drugs that lower blood pressure.
Thiazides are commonly used as an initial treatment of high blood pressures. They are sometimes used to decrease swelling and fluid retention associated with premenstrual syndrome , and corticosteroid or estrogen therapy. Thiazide diuretics may be used to treat diabetes insipidus , sometimes referred to as water diabetes. As a result, large amounts of urine are formed. If inadequate fluids are consumed, the loss of excess water may cause dehydration and high blood sodium.