Nitrates can cause headaches and reflex tachycardia as side effects. They are contraindicated in those with traumatic head injuries due to increased intracranial pressure or hypersensitivity. Caution should be used in those taking antihypertensives, and those with renal or liver impairment as there may be interactions. Nitrates may interact with beta blockers, calcium channel blockers, diuretics and PDE5 inhibitors causing hypotension. Drinking alcohol may also cause hypotension. If taking nitrates for chest pain, the patient should stop activity, sit or lie down, and not take more than 3 tablets. They should let the tablets dissolve under the tongue for 5 minutes and call 911 if pain is