A patient receiving Morphine for postoperative pain relief displays slow, shallow breathing with a rate of 8 breaths/minute. The nurse recognizes this as a side effect called:

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.

Choice A reason: “This medication should be taken after eating to reduce nausea.” is not a correct statement that demonstrates understanding about ondansetron. Ondansetron is a medication that prevents nausea and vomiting by blocking the action of serotonin, a chemical that stimulates the vomiting center in the brain. Ondansetron can be taken with or without food, and it does not affect the digestion or absorption of food. Ondansetron is usually taken before the start of chemotherapy, radiation, or surgery, which are the common causes of nausea and vomiting.

Choice B reason: “This medication should not be taken with starfruit.” is not a correct statement that demonstrates understanding about ondansetron. Ondansetron is a medication that prevents nausea and vomiting by blocking the action of serotonin, a chemical that stimulates the vomiting center in the brain. Ondansetron does not interact with starfruit, which is a tropical fruit that contains substances that can inhibit the enzyme CYP3A4, which is involved in the metabolism of many drugs. Ondansetron is mainly metabolized by another enzyme, CYP1A2, and it has a low potential for drug interactions¹.

Choice C reason: “This medication may make me tired and confused.” is a correct statement that demonstrates understanding about ondansetron. Ondansetron is a medication that prevents nausea and vomiting by blocking the action of serotonin, a chemical that stimulates the vomiting center in the brain. Ondansetron can also cross the blood brain barrier and affect other serotonin receptors in the brain, which are involved in regulating mood, cognition, and sleep. Ondansetron can cause side effects such as fatigue, drowsiness, headache, and confusion, which can impair the mental alertness and performance of the client. The client should be advised to avoid driving, operating machinery, or doing other tasks that require attention after taking ondansetron.

Choice D reason: “This medication may cause rebound nausea.” is not a correct statement that demonstrates understanding about ondansetron. Ondansetron is a medication that prevents nausea and vomiting by blocking the action of serotonin, a chemical that stimulates the vomiting center in the brain. Ondansetron does not cause rebound nausea, which is a condition of nausea that occurs after the discontinuation of a medication that suppresses nausea. Ondansetron is not a medication that suppresses nausea, but rather prevents it by blocking the stimulation of the vomiting center. Ondansetron does not cause dependence or withdrawal symptoms, and it can be stopped without causing rebound nausea.