A 73-year-old male patient is in the clinic for a yearly physical and is asking for a prescription for sildenafil. He has listed on his health history that he is taking a nitrate for angina. The nurse is aware that which problem may occur if sildenafil is taken with a nitrate?

Choice A reason: This is incorrect because the patient may not see a response from the medication for at least six months. The patient should continue taking the medication as prescribed and follow up with the provider regularly.

Choice B reason: This is correct because finasteride can cause birth defects in male fetuses if it is absorbed through the skin or ingested by pregnant women. The patient should wear gloves when handling the tablets and avoid contact with crushed or broken tablets.

Choice C reason: This is incorrect because PSA levels will decrease while taking this medication. PSA stands for prostate-specific antigen, which is a marker for prostate cancer. The patient should inform the provider that they are taking finasteride before having a PSA test, as it may affect the results.

Choice D reason: This is incorrect because grapefruit juice does not interact with finasteride. However, the patient should avoid alcohol and other medications that may affect the liver while taking finasteride.

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.