When educating a patient about Lorazepam (Ativan), the nurse should advise against the concurrent use of which substance?

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.

Choice A reason: This is correct. The liver is the main organ responsible for drug metabolism. The enzymes that the body uses to metabolize drugs are present throughout the body but are most abundant in the liver. The liver can transform drugs into more polar and water-soluble compounds, which can then be excreted by the kidneys or the biliary system.

Choice B reason: This is incorrect. The lungs are not primarily responsible for drug metabolism, although they can play a minor role in some cases. The lungs can metabolize some drugs that are inhaled, such as anesthetics, or drugs that circulate through the pulmonary blood vessels, such as propranolol. However, the lungs have a lower capacity and a lower variety of enzymes than the liver.

Choice C reason: This is incorrect. The heart is not responsible for drug metabolism, although it can be affected by it. The heart is the organ that pumps blood throughout the body, delivering oxygen and nutrients to the tissues and organs. The heart can be influenced by the pharmacokinetics and pharmacodynamics of drugs, which are the processes of drug absorption, distribution, metabolism, and excretion, and the effects of drugs on the body, respectively.

Choice D reason: This is incorrect. The kidney is not primarily responsible for drug metabolism, although it is important for drug excretion. The kidney is the organ that filters the blood and removes waste products and excess fluid as urine. The kidney can excrete drugs that are water-soluble or that are not reabsorbed by the tubules. The kidney can also metabolize some drugs, such as aspirin, but to a lesser extent than the liver.