Which of the following would the nurse correctly include in client teaching about nitroglycerin (Nitrostat)? (Select all that apply.)

A. Sublingual nitroglycerin tablets should be placed under the tongue and allowed to dissolve to ensure proper absorption. B. The medication should be kept in its original container to protect it from heat and light, which can degrade its effectiveness. C. Nitroglycerin should be replaced regularly when it is past its expiration date to ensure its efficacy. D. Taking nitroglycerin while lying or sitting can help prevent dizziness or fainting, and patients should change positions slowly to avoid orthostatic hypotension. E. A headache is a common side effect of nitroglycerin, and it should not necessarily lead to discontinuation of the medication without consulting a healthcare provider.