A patient will be starting therapy with a corticosteroid. The nurse reviews the prescriber's orders and notes that an interaction may occur if the corticosteroid is taken with which of these drug classes?

Choice A reason: Tachycardia is a possible adverse effect of theophylline, as it is a methylxanthine that stimulates the central nervous system and the cardiac muscle. The nurse should instruct the client to monitor their pulse rate and report any palpitations, chest pain, or irregular heartbeat.

Choice B reason: Drowsiness is not a likely adverse effect of theophylline, as it is a stimulant that increases alertness and energy. The nurse should caution the client to avoid taking the medication close to bedtime, as it may cause insomnia.

Choice C reason: Constipation is not a common adverse effect of theophylline, as it does not affect the gastrointestinal motility or secretion. The nurse should advise the client to maintain a balanced diet, adequate fluid intake, and regular exercise to prevent constipation.

Choice D reason: Oliguria is not a typical adverse effect of theophylline, as it does not impair the renal function or cause fluid retention. The nurse should encourage the client to drink enough fluids to prevent dehydration and maintain a normal urine output.

Choice A reason: This is incorrect because NPH insulin is normally cloudy and should be gently mixed before use. However, the nurse should discard the solution if it has clumps, flakes, or crystals.

Choice B reason: This is correct because NPH insulin is an intermediate-acting insulin that has a slower onset and longer duration than short-acting or rapid-acting insulins. The nurse should explain to the client that NPH insulin provides basal coverage and may need to be combined with other types of insulin to control blood glucose levels.

Choice C reason: This is incorrect because freezing insulin can damage its potency and effectiveness. The nurse should instruct the client to store unopened insulin vials in the refrigerator and opened vials at room temperature.

Choice D reason: This is incorrect because shaking insulin can cause air bubbles and frothing, which can affect the accuracy of the dose. The nurse should instruct the client to roll the insulin vial between the palms of the hands to mix it gently.