Decreased blood potassium levels; anxiety; fainting (syncope); sensation of tingling, pins and needles (paraesthesia); feeling of spinning (vertigo); fast heart beat (tachycardia), heart rhythm disorders, low blood pressure, a sudden fall in blood pressure when you stand up; shortness of breath (dyspnoea); symptoms of an upset stomach such as diarrhoea; dry mouth, flatulence; back pain, muscle spasm, muscle pain; erectile dysfunction (inability to get or keep an erection); chest pain; and increased blood uric acid levels.