Drug Interactions
An 80-year-old taking warfarin starts using ibuprofen every day for arthritis. What is the main concern?
Increased bleeding risk. Assess for bleeding, review the need for the NSAID, and coordinate a safer pain-management plan.
The prescription says metformin 500 mg twice daily. The patient takes it once each morning because she misunderstood the directions. Identify the problem.
A discrepancy between prescribed and actual use due to misunderstanding or unintentional nonadherence. Clarify the intended regimen and counsel; do not advise doubling a dose
A patient takes a prescribed twice-daily medication only once daily because she feels well. What should you ask first?
Ask the patient to describe exactly how and when she takes it and why she changed the schedule. Explore misunderstanding, side effects, cost, access, and routine before counseling.
An 86-year-old taking diphenhydramine nightly develops confusion and has two recent falls. What medication-related concern is likely?
Anticholinergic effects, sedation, confusion, and fall risk. Recommend prompt medication review and assessment for other causes of acute confusion or falls.
A patient says, 'I take my husband's pain pill whenever I run out of mine.' What is your first concern?
Unknown medication exposure, contraindications, interactions, and dosing. Identify the product and amount taken, assess immediate symptoms, counsel against medication sharing, and arrange appropriate review
An older adult takes lisinopril, spironolactone, and potassium chloride. What potentially dangerous laboratory abnormality can result?
Hyperkalemia. These agents can increase potassium, especially with impaired kidney function. Verify the indication, potassium, renal function, and monitoring plan.
A patient has an old furosemide 20 mg bottle and a new 40 mg bottle. She takes one tablet from each every morning. What should you investigate?
Possible unintended dose stacking. Verify the current prescribed dose, whether the old order was discontinued, and assess for dizziness, volume depletion, renal problems, and electrolyte abnormalities.
A patient forgets a morning blood pressure pill and takes two tablets the next morning to catch up. What is wrong?
Taking extra doses to compensate for a missed dose can cause harm. Explain that missed-dose instructions depend on the medication and that the patient should not double up unless specifically instructed.
An older adult on glipizide skips lunch and becomes sweaty, shaky, and confused. What should you suspect?
Possible hypoglycemia. Check glucose promptly if possible and follow the appropriate hypoglycemia response protocol. Severe confusion, seizure, unconsciousness, or inability to swallow requires emergency assistance.
A patient takes OTC ibuprofen daily but says it is not a medication because it came from a store. What should you do?
Include OTC medicines, supplements, and topical products in medication reconciliation. Assess dose, frequency, indication, interactions, kidney function, blood pressure, and bleeding risk.
A patient takes simvastatin 40 mg nightly and amlodipine 10 mg daily. Identify the interaction concern.
Amlodipine increases exposure to simvastatin. The recommended simvastatin maximum with amlodipine is 20 mg/day. Contact the prescriber to discuss an appropriate regimen.
A patient with a documented penicillin allergy receives a new amoxicillin prescription. The allergy reaction is not recorded. What is the appropriate action?
Clarify the allergy history and reaction with the patient and appropriate records, then consult the pharmacist/prescriber before dispensing. Do not assume the allergy is harmless or automatically confirms anaphylaxis.
An older adult takes levothyroxine with breakfast and calcium carbonate at the same time. What could happen?
Calcium can reduce levothyroxine absorption. Levothyroxine is generally taken consistently on an empty stomach, and calcium should be separated by at least four hours.
An 84-year-old with chronic kidney disease takes gabapentin and reports sleepiness and unsteadiness. What should be assessed?
Renal-dose appropriateness, sedation, gait/fall risk, other CNS depressants, and the current symptoms. Contact the pharmacist/prescriber for timely review.
An older adult taking zolpidem also takes lorazepam at bedtime and recently fell. What is the concern?
Additive CNS depression, sedation, impaired coordination, and fall risk. Review the combination with the pharmacist/prescriber and assess for injury or other urgent concerns.
An older adult takes sertraline and is prescribed tramadol. Which serious interaction risks should the pharmacist recognize?
Serotonin syndrome and increased seizure risk. Assess the full medication list, symptoms, and alternatives. Agitation, fever, sweating, tremor, clonus, or confusion warrant urgent assessment.
A patient brings a prescription reading 'take one tablet daily.' The drug name, strength, quantity, and dosage form are missing. Can it safely be processed?
No. Essential prescription information is missing. The order must be clarified with the prescriber in accordance with applicable law and policy before it can be safely processed
A patient crushes all tablets because swallowing is difficult, including an extended-release tablet. What should the pharmacist do?
Identify the exact products before any crushing. Crushing certain extended-release or enteric-coated products can change drug release and cause harm. Assess swallowing difficulties and consider suitable formulations.
An older adult taking digoxin develops nausea and yellow-tinted vision. What serious adverse effect should you suspect?
Possible digoxin toxicity. Arrange urgent medical assessment; evaluation may include ECG, renal function, electrolytes, and a properly timed digoxin concentration as clinically indicated.
A patient taking metformin 1,000 mg twice daily has an eGFR of 25 mL/min/1.73 m². What is the key medication issue?
Metformin is contraindicated when eGFR is below 30 mL/min/1.73 m². Promptly contact the treating clinician to address the regimen and assess the patient's condition; do not simply continue without review.
A patient with atrial fibrillation takes apixaban and starts naproxen OTC. She reports black, tarry stools. What is the priority?
Possible gastrointestinal bleeding. This requires emergency medical evaluation. Apixaban plus an NSAID increases bleeding risk. Do not delay care to finish a routine medication review.
A patient has active-looking bottles for both warfarin and apixaban after a hospital stay. She says nobody told her what to stop. What is the medication safety problem?
A potentially unsafe anticoagulant transition and unintended duplication. Urgently verify the discharge plan and next-dose instructions with the treating team/pharmacist. Do not independently invent a transition schedule.
An older adult sometimes repeats an insulin glargine injection because she cannot remember whether she took the first dose. What is the main risk and a practical intervention?
Duplicate insulin can cause serious hypoglycemia. Assess whether an extra dose was taken and current symptoms/glucose, escalating urgently when indicated. Develop a reliable dose-tracking routine with the care team
An 87-year-old taking metoprolol reports a pulse of 48 beats/minute and nearly fainted. What is the priority?
Possible symptomatic bradycardia. Near-fainting with a slow pulse requires urgent medical assessment; if symptoms are ongoing or severe, activate emergency services. Do not independently change the regimen.
An 85-year-old with heart failure and chronic kidney disease has new ankle swelling, takes naproxen daily, and feels dizzy when standing. Identify your priorities.
Assess urgency, vital signs, volume status, renal function, and electrolytes; naproxen can worsen fluid retention, heart failure, and kidney function. Escalate promptly based on symptoms, and seek emergency care for severe breathlessness, chest pain, fainting, or acute deterioration.