A nurse is preparing to administer phenylephrine as a vasopressor to treat a patient for hypotension. The desired therapeutic effect of phenylephrine in this context is:

Choice A reason: Tinnitus is a rare side effect of Flexeril, which is a medication that relaxes the muscles and relieves pain and stiffness¹. Tinnitus is a ringing or buzzing sound in the ears that can be caused by various factors, such as ear infections, noise exposure, or certain medications. Flexeril does not affect the auditory system directly, but it can cause confusion or dizziness, which may worsen the perception of tinnitus.

Choice B reason: Drowsiness is the most common side effect of Flexeril, which is a medication that relaxes the muscles and relieves pain and stiffness¹. Drowsiness occurs because Flexeril has sedative and anticholinergic properties, which means that it blocks the action of acetylcholine, a neurotransmitter that regulates arousal and alertness. Flexeril can impair the mental and physical abilities, especially in elderly patients or those who take other medications that cause drowsiness¹. The nurse should educate the patient about the risk of drowsiness and advise them to avoid driving or operating machinery while taking Flexeril.

Choice C reason: Diarrhea is not a common side effect of Flexeril, which is a medication that relaxes the muscles and relieves pain and stiffness¹. Diarrhea is a condition that causes loose or watery stools, which can be caused by various factors, such as infections, food intolerance, or certain medications. Flexeril does not affect the gastrointestinal system directly, but it can cause dry mouth, nausea, or constipation, which may alter the bowel movements¹.

Choice D reason: Palpitations are not a common side effect of Flexeril, which is a medication that relaxes the muscles and relieves pain and stiffness¹. Palpitations are a sensation of rapid or irregular heartbeat, which can be caused by various factors, such as stress, anxiety, caffeine, or certain medications. Flexeril does not affect the cardiac system directly, but it can lower the blood pressure or interact with other medications that affect the heart rate, such as betablockers or antidepressants¹.

Choice A reason: Vasodilation is not the primary therapeutic effect of atropine in this scenario. Atropine is a medication that blocks the action of acetylcholine, a neurotransmitter that stimulates the parasympathetic nervous system. Atropine can cause vasodilation by inhibiting the muscarinic receptors on the blood vessels, which normally cause vasoconstriction. However, this effect is not significant or consistent, and it does not improve the symptoms of bradycardia, which is a slow heart rate that can cause dizziness, fatigue, or fainting. The nurse should monitor the blood pressure and the peripheral pulses of the patient after administering atropine.

Choice B reason: Bronchodilation is not the primary therapeutic effect of atropine in this scenario. Atropine is a medication that blocks the action of acetylcholine, a neurotransmitter that stimulates the parasympathetic nervous system. Atropine can cause bronchodilation by inhibiting the muscarinic receptors on the bronchial smooth muscle, which normally cause bronchoconstriction. However, this effect is not relevant or beneficial for the patient with symptomatic bradycardia, who does not have any respiratory problems. The nurse should assess the respiratory rate and the breath sounds of the patient after administering atropine.

Choice C reason: Increase in heart rate is the primary therapeutic effect of atropine in this scenario. Atropine is a medication that blocks the action of acetylcholine, a neurotransmitter that stimulates the parasympathetic nervous system. Atropine can increase the heart rate by inhibiting the muscarinic receptors on the sinoatrial node and the atrioventricular node, which normally slow down the heart rate. This effect is desirable and beneficial for the patient with symptomatic bradycardia, who has a slow heart rate that can cause dizziness, fatigue, or fainting. The nurse should monitor the electrocardiogram and the heart rate of the patient after administering atropine.

Choice D reason: Diuresis is not the primary therapeutic effect of atropine in this scenario. Atropine is a medication that blocks the action of acetylcholine, a neurotransmitter that stimulates the parasympathetic nervous system. Atropine can cause diuresis by inhibiting the muscarinic receptors on the bladder, which normally promote urination. However, this effect is not important or helpful for the patient with symptomatic bradycardia, who does not have any urinary problems. The nurse should measure the urine output and the specific gravity of the patient after administering atropine.