Medication Interactions And Contraindications - NCLEX Pn

Which order should be questioned in a child with chickenpox: aspirin or acetaminophen?

Aspirin. Aspirin in the context of varicella infection heightens the likelihood of mitochondrial injury and subsequent Reye syndrome development.
Which OTC product should be avoided with SSRIs due to serotonin syndrome risk: dextromethorphan or guaifenesin?

Dextromethorphan. Dextromethorphan acts as a serotonin reuptake inhibitor, amplifying SSRI effects and risking serotonin overload.
Which medication should be avoided with grapefruit juice due to increased drug levels: simvastatin or amoxicillin?

Simvastatin. Grapefruit juice inhibits CYP3A4 in the intestine, decreasing simvastatin's first-pass metabolism and raising systemic exposure.
What is the contraindication for giving beta blockers to a patient with severe asthma and active bronchospasm?

Risk of bronchoconstriction (avoid nonselective beta blockers). Nonselective beta blockers antagonize beta-2 receptors in bronchial smooth muscle, precipitating airway narrowing in asthmatic patients.
What interaction reduces absorption of tetracyclines and fluoroquinolones when taken with milk or antacids?

Chelation with calcium/iron/magnesium reduces absorption. These cations form insoluble complexes with the antibiotics in the gut, impairing their bioavailability.
What interaction occurs when potassium supplements are taken with spironolactone?

Hyperkalemia risk. Spironolactone's potassium-sparing action combined with exogenous potassium can disrupt electrolyte balance, leading to cardiac arrhythmias.
What is the key interaction concern when warfarin is combined with NSAIDs (for example, ibuprofen)?

Increased bleeding risk. NSAIDs inhibit platelet aggregation and can displace warfarin from plasma proteins, potentiating its anticoagulant effects.
Which medication is contraindicated in a patient with a history of anaphylaxis to penicillin: amoxicillin or acetaminophen?

Amoxicillin. As a beta-lactam antibiotic, amoxicillin can trigger cross-reactive IgE-mediated hypersensitivity in penicillin-allergic individuals.
Which medication is contraindicated in a patient using nitrates for angina: sildenafil or acetaminophen?

Sildenafil. Sildenafil inhibits PDE-5, synergizing with nitrates to cause excessive cyclic GMP accumulation and vasodilatory hypotension.
Which medication class is contraindicated in pregnancy due to fetal renal injury (oligohydramnios) risk: ACE inhibitors or antacids?

ACE inhibitors (and ARBs) are contraindicated in pregnancy. These drugs disrupt the fetal renin-angiotensin system, causing renal agenesis, oligohydramnios, and other teratogenic effects during pregnancy.
Which interaction occurs when digoxin is taken with loop diuretics that cause hypokalemia?

Increased digoxin toxicity risk. Hypokalemia sensitizes the myocardium to digoxin by increasing its binding to Na+/K+-ATPase, heightening arrhythmic potential.
Which interaction is most important with alcohol and acetaminophen use?

Increased hepatotoxicity risk. Alcohol induces CYP2E1, accelerating acetaminophen conversion to the hepatotoxic metabolite NAPQI, overwhelming glutathione stores.
What is the most serious interaction risk when nitrates are taken with sildenafil or other PDE-5 inhibitors?

Severe hypotension (potentially life-threatening). Nitrates and PDE-5 inhibitors both promote vasodilation through nitric oxide pathways, leading to profound and potentially fatal blood pressure drops.
Identify the unsafe combination: warfarin plus trimethoprim-sulfamethoxazole or warfarin plus acetaminophen.

Warfarin plus trimethoprim-sulfamethoxazole. Trimethoprim-sulfamethoxazole inhibits CYP2C9, reducing warfarin metabolism and amplifying its anticoagulant activity.
What drug and food interaction requires avoiding aged cheese and cured meats while taking an MAOI?

Tyramine interaction causing hypertensive crisis. MAOIs prevent the breakdown of tyramine from fermented foods, resulting in excessive norepinephrine release and acute hypertension.
Which antibiotic class should be avoided with warfarin due to increased INR risk: macrolides or penicillins?

Macrolides (for example, erythromycin) increase INR. Macrolides inhibit CYP3A4-mediated metabolism of warfarin, elevating its plasma levels and prolonging INR.
What is the key interaction concern when alcohol is taken with metronidazole?

Disulfiram-like reaction. Metronidazole inhibits aldehyde dehydrogenase, causing acetaldehyde accumulation and symptoms like flushing and nausea.
What is the key interaction concern when aspirin is combined with warfarin?

Markedly increased bleeding risk. Aspirin's antiplatelet effects additively impair hemostasis when combined with warfarin's inhibition of clotting factors.
What interaction risk occurs when SSRIs are taken with MAOIs or linezolid?

Serotonin syndrome. These combinations excessively elevate serotonin levels in the central nervous system, precipitating symptoms like agitation and hyperthermia.
Which instruction is correct for levothyroxine and iron supplements: take together or separate by at least $4$ hours?

Separate by at least $4$ hours. Iron binds to levothyroxine in the gastrointestinal tract, forming complexes that reduce thyroid hormone absorption.
Which drug is contraindicated with chronic NSAID use due to lithium toxicity risk: lithium or levothyroxine?

Lithium (NSAIDs can increase lithium levels). NSAIDs reduce renal clearance of lithium by decreasing prostaglandin-mediated blood flow, elevating serum concentrations.
What is the major interaction risk when opioids are combined with benzodiazepines?

Additive CNS/respiratory depression. Both drug classes suppress central nervous system activity, synergistically causing profound sedation and respiratory failure.
What is the contraindication to giving aspirin to children with suspected viral illness (influenza or varicella)?

Risk of Reye syndrome. Aspirin use during viral infections in children is associated with mitochondrial dysfunction, leading to encephalopathy and fatty liver degeneration.
Which antibiotic is contraindicated in pregnancy due to tooth discoloration and inhibited bone growth?

Tetracyclines (for example, doxycycline). Tetracyclines bind to calcium in developing fetal tissues, leading to permanent enamel hypoplasia and skeletal abnormalities.
Identify the contraindication: warfarin use in a patient with active GI bleeding.

Contraindicated due to high bleeding risk. Warfarin's anticoagulant properties exacerbate ongoing hemorrhage by inhibiting vitamin K-dependent clotting factors.

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