Patients w/ excessive vomiting or diarrhea; kidney, heart or liver problems; recent kidney transplant; DM; hypoglycemia, particularly during DM treatment; SLE; primary aldosteronism; skin cancer or development of an unexpected skin lesion during treatment; breathing or lung problems following previous hydrochlorothiazide intake; low-salt diet; signs indicative of excessive effect of hydrocholorothiazide; increased skin sensitivity to the sun w/ symptoms of sunburn occurring more quickly than normal; intolerance to some sugars. Increased risk of non-melanoma skin cancer w/ hydrochlorothiazide, particularly w/ long-term use of high doses. Protect skin from sun exposure & UV rays during treatment. Regularly check the skin for any new lesions. Risk of idiosyncratic reaction, which may result in choroidal effusion, secondary acute angle-closure glaucoma &/or acute transient myopia. Dual blockade of renin-angiotensin-aldosterone system through combined use of ACE-inhibitors, ARBs or aliskiren is not recommended. Check kidney function, BP, & electrolyte levels (eg, K) in the blood at regular intervals. +ve result in anti-doping test. Occasional dizziness or weariness may occur during treatment. Not recommended in early pregnancy & in breast-feeding women. Do not use in childn & adolescents <18 yr.