NCLEX : Drug Interactions and Biotransformation

Study concepts, example questions & explanations for NCLEX

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Example Questions

Example Question #6 : Side Effects

Which of the following medications is associated with increased risk of SIADH (syndrome of inappropriate antidiuretic hormone secretion)?

Possible Answers:

Chlorpropamide

Metronidazole

Eszopiclone

Drospirenone 

Correct answer:

Chlorpropamide

Explanation:

Chlorpropamide, an antidiabetic medication in the sulfonylurea class, has been associated with drug-induced SIADH (syndrome of inappropriate antidiuretic hormone secretion). This is a rare but serious complication that will generally resolve once drug treatment has stopped. None of the other drugs listed are associated with this side effect. 

Example Question #7 : Side Effects

Which of the following medications can cause the (benign) side effect of causing an orange-red tint to urine and tears?

Possible Answers:

Rifampicin

Vancomycin

Metronidazole

Clindamycin

Correct answer:

Rifampicin

Explanation:

Of the drugs listed, the only one associated with this bizarre side effect is rifampicin, a broad spectrum antibiotic used in tuberculosis. Urine, sweat, saliva, or tears may be turned any shade from red to reddish orange.

Example Question #7 : Side Effects

Which of the following antibiotics is potentially ototoxic and may cause irreversible hearing loss? 

Possible Answers:

Azithromycin

Penicillin 

Gentamicin

Doxycycline

Correct answer:

Gentamicin

Explanation:

Gentamicin is an aminoglycoside antibiotic. Most antibiotics in the aminoglycoside class can have significant ototoxic effects. Of these, streptomycin and gentamicin are primarily toxic to the vestubular system, while amikacin, neomycin, dihydrosterptomycin, and kanamicin primarily affect the cochlea. None of the other antibiotics listed are generally associated with ototoxicity.

Example Question #61 : Nclex

A 24 year old female presents with a simple urinary tract infection, for which she is prescribed ciprofloxacin. What is the most severe potential side effect of this medication?

Possible Answers:

Tendon injury or rupture (especially Achilles tendon)

Kidney failure

Seizures

Hepatotoxicity

Correct answer:

Tendon injury or rupture (especially Achilles tendon)

Explanation:

Ciprofloxacin has been associated with several cases of tendon injury and rupture, with the typical rupture occuring in the Achilles tendon. Other less severe side effects can include nausea and vomiting, headache, insomnia, and increased sensitivity to caffeine. The other symptoms listed are not generally associated with ciprofloxacin use.

Example Question #62 : Nclex

Which of the following antibiotics is strictly contraindicated in pregnancy, in lactating mothers, or in children under 8 years old, due to risk of irreversible teeth staining?

Possible Answers:

Rifaximin

Tetracycline 

Clindamycin

Ceftazidime

Correct answer:

Tetracycline 

Explanation:

Tetracycline antibiotics are strictly contraindicated in pregnancy, in lactating mothers, or in children under 8 years old, due to risk of irreversible teeth staining. The discoloration occurs only in adult teeth that have not broken the gum-line, so adults are not at risk.

Example Question #63 : Nclex

A 42 year old man with a history of severe depression who is currently prescribed multiple antidepressants presents with tachycardia, hyperreflexia, sweating, mydriasis, myoclonus. He is confused and mildly agitated. On questioning he admits that he may have taken "one too many" of one or more of his medications. What is the most likely cause of his symptoms?

Possible Answers:

Serotonin syndrome

Hypertensive crisis

Extrapyramidal side effects

Tardive dyskinesia

Correct answer:

Serotonin syndrome

Explanation:

The symptoms this patient are presenting with are consistent with serotonin syndrome, a rapid onset and potentially life-threatening condition of excess circulating serotonin. Symptoms can range from mild to severe, and may include tachycardia, nausea and vomiting, diarrhea, hyperreflexia, sweating, mydriasis, myoclonus, mental status changes, headache, and coma. Serotonin syndrome is generally caused by drug interaction or overdose of drugs that raise circulating serotonin levels, such as selective serotonin reuptake inhibitors (SSRI's) and monoamine oxidase inhibitors (MAOI's). 

Example Question #64 : Nclex

A 63 year old female presents with involuntary grimacing, lip smacking, excessive blinking, and sticking out of the tongue. She also flicks her fingers and her wrists. She states that she has no control over these movements, and that they have gotten progressively worse over the last three years. Her family is worried that she may be experiencing an early form of dementia. Her medical history is significant for depression, for which she has been taking aripiprazole for the last nine years. Which of the following is the most likely cause of her symptoms?

Possible Answers:

Worsening depression

Tardive dyskinesia

Serotonin syndrome

Early-onset alzheimer's disease

Correct answer:

Tardive dyskinesia

Explanation:

The most likely cause of uncontrollable muscle movements in the absence of other systemic symptoms in a patient with a history of antipsychotic drug use is tardive dyskinesia. This is a disorder of rapid involuntary movements, most often in the face or head but also potentially affecting the extremities. It's exact cause is not well understood, but it is theorized to be an issue of sensitization of the D2 dopamine receptors after long-term neuroleptic use. 

Example Question #65 : Nclex

 Which of the following is not a common side effects in individuals using selective serotonin reuptake inhibitors (SSRI's)? 

Possible Answers:

Increased risk of suicide in children and adolescents

Increased risk of bone fracture

Coronary heart disease

Low libido

Correct answer:

Coronary heart disease

Explanation:

While SSRI's have been known to cause a variety of adverse effects, including diminished libido, increased risk of suicide in children and adolescents, restlessness, photosensitivity, and increased risk of bone fracture, individuals taking SSRI's are not associated with any increased incidence of coronary heart disease.

Example Question #66 : Nclex

Which of the following over-the-counter medications has been associated with hepatotoxicity and liver failure?

Possible Answers:

Cetirizine

Acetylsalicylic acid

Acetaminophen

Diphenhydramine

Correct answer:

Acetaminophen

Explanation:

Acetaminophen has surpassed viral hepatitis as the most common cause of acute hepatic failure in the United States. Hepatotoxicity can occur in doses of 7.5g or up for adults and 150millg/kg of body weight in children aged 1-6. None of the other drugs listed are particularly hepatotoxic.

Example Question #67 : Nclex

What is the mechanism of cytotoxicity in acetaminophen-related liver failure?

Possible Answers:

Blockage of bile canaliculi

Depletion of glutathione

Formation of fatty infiltrates

Fibrosis of hepatocytes

Correct answer:

Depletion of glutathione

Explanation:

Acetaminophen depletes glutathione, one of the body's most important antioxidants. The liver is the body's main processing organ for environmental and ingested toxins, and glutathione is the primary molecule the liver uses to rid itself of the harmful biproducts of the detoxification process. When glutathione is severely depleted, such as with acetaminophen overdose, hepatic cells can rapidly necrose, resulting in liver failure and even death. 

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