NCLEX : Drug Interactions and Biotransformation

Study concepts, example questions & explanations for NCLEX

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Example Questions

Example Question #1 : Drug Interactions And Biotransformation

A 65-year-old male client is being discharged from the hospital on warfarin therapy for chronic atrial fibrillation. The nurse is aware that the discharge teaching needs to include which of the following instructions?

Possible Answers:

Alcohol should be limited to no more 1-2 servings on an occasional basis

Increase intake of leafy green vegetables

When having dental procedures there is no need to discontinue warfarin

Warfarin is a medication that does not require monitoring

Use a blade when shaving; avoid electric razors

Correct answer:

Alcohol should be limited to no more 1-2 servings on an occasional basis

Explanation:

Warfarin is an anticoagulant, alcohol can increase this effect, so it should be limited or avoided. Leafy greens, contain vitamin K and can reverse the action of warfarin. Warfarin needs monthly monitoring to check client internal normalized ratio (INR). Dental and surgical procedures may require discontinuation temporarily to avoid excess bleeding. Electric razors are preferred.

Example Question #1 : Drug Interactions And Biotransformation

A nurse checks the lithium level of a 28-year-old patient that has been prescribed lithium citrate and sees the level is 1.5 mEq/L, and verifies that the patient has not taken more than the prescribed medication. The nurse advises the client to:

Possible Answers:

Eat more red meat

Exercise more often

Drink 4 glasses of water a day

Eat salty foods

Correct answer:

Eat salty foods

Explanation:

Low sodium diets when taking lithium mood-stabilizing drugs can result in toxicity. The nurse should tell the patient to eat salty foods to increase sodium intake.

Example Question #41 : Pharmacology

The nurse cares for a patient with a urinary tract infection (UTI). The patient has an allergy to penicillins. Which of the following medications is contraindicated for this patient’s illness?

Possible Answers:

Clindamycin

Streptomycin

Sulfasalazine

Ciprofloxacin

Ceftriaxone

Correct answer:

Ceftriaxone

Explanation:

Patients with allergies to penicillins often have cross-allergies to cephalosporins. Cephalosporins such as ceftriaxone should be avoided by patients with these allergies. Patients with cephalosporin allergies should also avoid pencillins. Streptomycin, ciprofloxacin, clindamycin, and sulfasalazine may all treat UTIs but are not penicillins.

Example Question #42 : Pharmacology

The nurse assesses patient medications at a primary care clinic. Which of the following patients with osteoporosis should not be prescribed alendronate?

Possible Answers:

A 58-year-old female taking estrogen.

A 70-year-old female with chronic kidney disease.

A 53-year-old female taking captopril.

A 62-year-old female on a low-calorie diet.

A 65-year-old female who is allergic to iodine.

Correct answer:

A 70-year-old female with chronic kidney disease.

Explanation:

The nurse should identify alendronate as a medication that slows bone loss, and is commonly prescribed to patients with osteoporosis to maintain bone density. The nurse should assess ages and risk factors associated with both osteoporosis and alendronate use. Alendronate is contraindicated in patients who are allergic to it, have esophageal issues such as narrowing or blockages, are unable to sit or stand upright for 30 minutes (after taking), or have kidney dysfunction or low blood calcium levels. Therefore, the nurse should question the order of alendronate for the 70-year-old female with chronic kidney disease. The nurse should also recognize that older patients are more likely to experience problems such as contraindications with medications due to polypharmacy, so the age of the 70-year-old female should concern the nurse. Alendronate is not contraindicated in patients who are on low-calorie diets, and it is not contraindicated with estrogen or captopril.

Example Question #3 : Drug Interactions And Biotransformation

The pediatric oncology nurse talks to relatives of a child with leukemia. The patient’s uncle wants to donate blood for transfusion. Which of the following donor conditions would preclude him from donating blood?

Possible Answers:

A previous cholecystectomy 2 years ago

A diagnosis of diverticulosis 10 years ago

A history of Crohn’s disease in remission 3 years

A history of hepatitis C 4 years ago

A  dose of ibuprofen 20 hours ago

Correct answer:

A history of hepatitis C 4 years ago

Explanation:

Blood donors must be healthy and feeling well to donate blood; they must also be free of blood-borne pathogens such as HIV/AIDS and hepatitis B, C, and D. Diverticulosis, Crohn’s disease, a previous cholecystectomy, and a dose of ibuprofen the previous day do not preclude this person from donating blood.

Example Question #3 : Drug Interactions

The nurse reviews medication orders for a patient with acute gastritis. Which of the following medications is contraindicated for this patient?

Possible Answers:

Acetaminophen

Ibuprofen

Calcium supplements

Furosemide

Propranolol

Correct answer:

Ibuprofen

Explanation:

Patients with acute gastritis experience inflammation in the gastric mucosa. They must discontinue use of drugs that may cause gastritis or inflammation, such as NSAIDs like ibuprofen or alcohol consumptions. Calcium gluconate, furosemide, acetaminophen, and propranolol are not associated with acute gastritis and can be taken safely by this patient.

Example Question #5 : Drug Interactions

Which of the following high-tyramine foods should be avoided by individuals taking monoamine oxidase inhibitors (MAOI's)?

Possible Answers:

Charred, toasted, or roasted foods; glazes, added sweeteners, and syrups

Leafy green vegetables, sweet potatoes, tomatoes

Pumpkin, sesame, and sunflower seeds; brassicas

Aged, smoked, fermented, or pickled foods; pork; chocolate

Correct answer:

Aged, smoked, fermented, or pickled foods; pork; chocolate

Explanation:

Tyramine is an amino-acid that is present in many foods, including fermented, aged, or smoked foods, aged cheese, fish, pork, cold cuts, chocolate, alcohol, yeasty breads, peanuts, and beans. High tyramine intake in patients on MAOI's can cause hypertensive crisis due to monoamine oxidase's role in tyramine breakdown.

Example Question #42 : Pharmacology

Patients taking which of the following antibiotics should be cautioned against any alcohol consumption?

Possible Answers:

Neomycin

Mupirocin

Metronidazole

Penicillin

Correct answer:

Metronidazole

Explanation:

Drinking alcohol while taking metronidazole can result in nausea, vomiting, flushing, and tachycardia. This is due to metronidazole's inhibition of acetaldehyde dehydrogenase, the enzyme responsible for acetaldehyde catabolism. Reduced function of acetaldehyde dehydrogenase results in toxic levels of acetaldehyde in the blood.

Example Question #2 : Drug Interactions And Biotransformation

Monoamine oxidase inhibitors (MAOI's) should not be combined with foods that contain large amounts of what monoamine?

Possible Answers:

Tyramine

Synephrine

Epinephrine

Histamine

Correct answer:

Tyramine

Explanation:

Tyramine is normally broken down by monoamine oxidase. Monoamine oxidase inhibitors prevent the breakdown and removal, leading abnormally high tyrosine levels in the body. This can in turn displace the storage and increase release of multiple other catecholamines, including dopamine, epinephrine, and norepinephrine. This increase in free catecholamines can cause a hypertensive crisis.

Example Question #1 : Drug Interactions And Biotransformation

You are the nurse taking care of a patient who is being discharged on warfarin for a pulmonary embolism. Which of the following statements would you most likely give when counseling the patient about warfarin use?

Possible Answers:

"Do not consume grapefruit juice when taking warfarin."

"Your risk of bleeding events is not significantly elevated while taking warfarin."

"You can discontinue taking aspirin, if you were already taking aspirin, while you are taking warfarin."

"You have an increased risk of seizures while taking warfarin."

"You can participate in all physical activities, including contact sports, while taking warfarin."

Correct answer:

"Do not consume grapefruit juice when taking warfarin."

Explanation:

The correct answer is "Do not consume grapefruit juice while taking warfarin." 

This advice is correct because warfarin is metabolized and inactivated by the cytochrome P-450 (CYP450) enzyme complex, and grapefruit juice is an inhibitor of CYP450. Therefore, when grapefruit juice is consumed, the efficacy of inactivation of drugs, like warfarin, is impaired, which increases the effective level of warfarin circulating in the patient's blood. Consequently, even if the patient is taking the prescribed dose of warfarin, the effect of the drug may be greater than intended if taken with grapefruit juice, which can predispose to dangerous, potentially fatal bleeding effects. Thus, avoiding grapefruit juice while taking warfarin is the most appropriate advice for this patient.

The patient's risk of bleeding events is elevated while taking warfarin, even without consuming grapefruit juice, though the benefit of preventing future blood clots and pulmonary emboli outweighs the risk of bleeding. Due to the risk of bleeding events while taking warfarin, it would be inappropriate to advise the patient to continue participating in contact sports.

Warfarin is not known to cause an increased risk of seizures.

It would be inappropriate to advise a patient to discontinue taking aspirin while on warfarin unless explicitly instructed for a medical reason by his physician. While aspirin is an anti-platelet agent, which can predispose to bleeding, and warfarin is an anti-coagulant, which also independently can predispose to bleeding, each medication has a clinical indication in the patient, and therefore it is inappropriate to simply discontinue one medication.

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