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Medication And Allergy History - NAPLEX

  1. A 28-year-old man (weight 88 kg) presents with a diffuse itchy rash and facial flushing after starting amoxicillin-clavulanate 875 mg/125 mg by mouth twice daily yesterday for sinusitis. He reports a prior "penicillin allergy" but says it was "just stomach upset" as a teenager. Current medications: none; takes cetirizine 10 mg by mouth daily as needed for seasonal allergies. Pertinent labs: SCr 0.9 mg/dL; AST/ALT within normal limits. Documented allergies in the profile: penicillin (gastrointestinal upset). What is the most significant allergy-related concern for this patient?
    Answer: The current rash and facial flushing after re-exposure may represent a true hypersensitivity reaction and should be documented with specific symptoms and timing This question tests evaluation of evolving allergic reactions and proper documentation of drug allergies. The key patient-specific factor is development of rash and facial flushing after amoxicillin-clavulanate in a patient with prior mild penicillin intolerance. The current reaction potentially representing true hypersensitivity (choice B) is the BEST answer because the new symptoms (rash, flushing) differ from the prior GI upset and could indicate IgE-mediated allergy development, requiring immediate discontinuation and proper documentation. Prior GI upset alone (choice A) doesn't confirm IgE-mediated allergy or predict current reaction severity. Cetirizine (choice C) is unlikely to cause this reaction pattern. Clavulanate (choice D) doesn't negate penicillin allergy risk as amoxicillin is still a beta-lactam. The clinical pearl is that drug allergy presentations can evolve over time, and any new cutaneous or systemic symptoms with re-exposure require careful evaluation, discontinuation, and detailed documentation of reaction type and timing.
  2. A 48-year-old male (weight 86 kg) comes in for a new patient consult and brings a handwritten list: "metoprolol 50 daily, Plavix 75, Protonix 40, insulin 10 at night." Medical history: coronary artery disease with stent, hypertension, and type 2 diabetes. Labs: serum creatinine 1.2 mg/dL, alanine aminotransferase 29 U/L, aspartate aminotransferase 25 U/L, hemoglobin A1c 8.3%. Allergies: "none." What is the most important step in verifying the patient's medication history?
    Answer: Confirm the exact metoprolol formulation (tartrate vs succinate) and dosing frequency with the previous pharmacy or prescription bottles This question tests precise medication reconciliation to distinguish formulations and prevent errors in chronic therapy. The key patient-specific factor is the vague 'metoprolol 50 daily' which could be tartrate (twice daily) or succinate (once daily), impacting efficacy post-stent. Confirming the exact formulation with prior sources is the best choice to ensure appropriate dosing and adherence. Assuming extended-release risks underdosing if tartrate, changing clopidogrel ignores guidelines, and converting pantoprazole is not equivalent. A transferable clinical pearl is that beta-blocker formulations differ in duration, affecting once- versus twice-daily use. Use a framework: clarify ambiguities in patient lists, verify with records, and reconcile for accuracy.
  3. A 71-year-old female (weight 60 kg) requests help because her blood pressure remains high despite medications. Medical history: hypertension, heart failure with preserved ejection fraction, and chronic kidney disease stage 3. Current medications per patient: "losartan 100 mg daily," "water pill," and "something for pain"; her profile shows losartan 100 mg daily, furosemide 20 mg daily, and meloxicam 15 mg daily. Labs: serum creatinine 1.6 mg/dL, potassium 5.4 mEq/L (high), alanine aminotransferase 26 U/L, aspartate aminotransferase 24 U/L. Allergies: "sulfa—rash." What is the most important step in verifying the patient's medication history?
    Answer: Clarify the exact OTC and prescription pain products used (including potassium-containing salt substitutes and NSAID frequency) and reconcile against fill history This question tests thorough medication history verification in patients with vague reporting and potential contributors to clinical issues like hyperkalemia. The key patient-specific factor is the high potassium level with losartan use, possibly exacerbated by unreported OTC NSAIDs or potassium-containing products. Clarifying exact OTC and prescription pain products against fill history is the best choice to identify hidden contributors and ensure accurate reconciliation. Discontinuing losartan ignores other factors, adding spironolactone worsens hyperkalemia, and documenting furosemide as allergy is incorrect as the sulfa rash may not cross-react. A transferable clinical pearl is that NSAIDs can potentiate hyperkalemia with renin-angiotensin system inhibitors. Use a framework: probe for OTC use, cross-check history, and address modifiable risks for better control.
  4. A 76-year-old woman (weight 58 kg) is a new patient establishing care at a community pharmacy after moving. She brings a handwritten list: "water pill," "heart pill," "thyroid pill," and "something for nerves," but no bottles. Medical history includes heart failure with reduced ejection fraction, hypothyroidism, chronic kidney disease stage 3, and generalized anxiety disorder. Pertinent labs from last month: SCr 1.6 mg/dL, potassium 4.9 mEq/L, thyroid-stimulating hormone (TSH) 6.8 mIU/L (high). Documented allergies: codeine (nausea/vomiting). What is the most important step in verifying the patient's medication history?
    Answer: Call the patient's previous pharmacy and prescribers to obtain an objective fill history and current doses before entering medications into the profile This question tests the importance of obtaining accurate medication histories in elderly patients with multiple chronic conditions. The key patient-specific factor is a new patient with vague medication descriptions and no medication bottles, making accurate reconciliation impossible. Calling previous pharmacy and prescribers for objective fill history (choice B) is the BEST answer because it provides verified medication names, doses, and adherence patterns essential for safe care. Starting levothyroxine based on TSH alone (choice A) is premature without knowing if she's already on thyroid medication. Making assumptions about generic drug names (choice C) is dangerous as many medications could be described as "water pill" or "heart pill." Ignoring OTC products (choice D) is incorrect as they can cause significant interactions. The clinical pearl is that objective verification through pharmacy records or prescriber offices is essential when patients cannot provide specific medication information, especially in elderly patients with polypharmacy.
  5. A 46-year-old female (weight 70 kg) is picking up a new prescription for warfarin 5 mg daily for a deep vein thrombosis. She reports taking "a lot of supplements" and OTC products: ibuprofen 400 mg as needed, aspirin 81 mg daily (self-started), and St. John's wort 300 mg three times daily for mood; she also takes sertraline 100 mg daily. Labs: international normalized ratio 1.0 (baseline), serum creatinine 0.9 mg/dL, alanine aminotransferase 24 U/L, aspartate aminotransferase 20 U/L. Allergies: none. Which medication requires verification due to potential interaction?
    Answer: St. John's wort 300 mg three times daily This question tests the recognition of herb-drug interactions affecting anticoagulation therapy. The key patient-specific factor is the use of St. John's wort with warfarin, which induces CYP enzymes and can decrease INR, risking subtherapeutic anticoagulation. St. John's wort requires verification because it can significantly reduce warfarin efficacy, potentially leading to thrombosis. Ibuprofen and aspirin may increase bleeding risk but are not the primary interaction here, and sertraline has a milder interaction potential. A transferable clinical pearl is that St. John's wort is a potent CYP3A4 inducer, interacting with many drugs like warfarin. Apply a framework: screen for supplements during reconciliation, assess interaction severity, and counsel on discontinuation or monitoring.
  6. A 69-year-old man (weight 84 kg) is admitted for pneumonia and is now transitioning to home. Discharge medications include: levofloxacin 750 mg by mouth daily for 5 days (new), prednisone 40 mg by mouth daily for 5 days (new), albuterol inhaler 2 puffs every 4–6 hours as needed, and his home medications: ferrous sulfate 325 mg by mouth daily, calcium carbonate 500 mg by mouth twice daily, and multivitamin 1 tablet by mouth daily. Pertinent labs: SCr 1.0 mg/dL; AST/ALT within normal limits. Documented allergies: "ciprofloxacin—tendon pain." Which medication requires verification due to potential interaction?
    Answer: Levofloxacin 750 mg by mouth daily because divalent cations (calcium, iron) can reduce absorption; verify administration timing separation This question tests recognition of chelation interactions between fluoroquinolones and polyvalent cations. The key patient-specific factor is concurrent administration of levofloxacin with multiple sources of divalent/trivalent cations (calcium, iron, multivitamin). Levofloxacin requiring timing verification (choice A) is the BEST answer because polyvalent cations can reduce fluoroquinolone absorption by up to 90% through chelation, requiring 2-hour separation before or 6 hours after cation administration. Multivitamins don't inactivate corticosteroids (choice B). Ferrous sulfate doesn't increase albuterol toxicity (choice C) or cause kidney injury with prednisone (choice D). The clinical pearl is that fluoroquinolones must be separated from calcium, iron, magnesium, aluminum, and zinc supplements by at least 2 hours to ensure adequate absorption, and this interaction is one of the most clinically significant drug-food/supplement interactions.
  7. A 56-year-old male (weight 83 kg) is discharged after a myocardial infarction. Discharge medications: aspirin 81 mg daily, ticagrelor 90 mg twice daily, atorvastatin 80 mg nightly, metoprolol succinate 50 mg daily, and nitroglycerin 0.4 mg sublingual as needed. He tells you he has been taking sildenafil 50 mg as needed for erectile dysfunction and asks if he can continue. Labs: serum creatinine 1.0 mg/dL, alanine aminotransferase 45 U/L (slightly high), aspartate aminotransferase 40 U/L. Allergies: none. What counseling point is crucial based on the patient's medication history?
    Answer: Avoid sildenafil while using nitroglycerin due to risk of severe hypotension; counsel on required separation and to seek medical advice before use This question tests counseling on critical drug interactions in post-myocardial infarction patients. The key patient-specific factor is the concomitant use of sildenafil and nitroglycerin, which can cause profound hypotension due to phosphodiesterase-5 inhibition potentiating nitrates. Advising avoidance and separation is the best choice to prevent life-threatening hypotension. Taking together worsens risks, stopping aspirin ignores its benefit, and increasing atorvastatin is unnecessary. A transferable clinical pearl is that PDE5 inhibitors require at least 24-hour separation from nitrates. Apply a framework: screen for erectile dysfunction agents, educate on risks, and coordinate with prescribers for alternatives.
  8. A 61-year-old female (weight 74 kg) reports she is "allergic to sulfa" because she developed a rash with sulfamethoxazole/trimethoprim years ago. She is now prescribed hydrochlorothiazide 25 mg daily for hypertension. Medical history: hypertension and osteopenia. Current medications: calcium carbonate 600 mg twice daily and vitamin D3 1000 units daily. Labs: serum creatinine 0.9 mg/dL, potassium 4.1 mEq/L, alanine aminotransferase 21 U/L, aspartate aminotransferase 19 U/L. Documented allergies: "sulfonamide antibiotic—rash." What is the most significant allergy-related concern for this patient?
    Answer: Clarify the prior reaction severity and counsel that cross-reactivity with nonantibiotic sulfonamides is low; monitor for rash after initiation This question tests the understanding of cross-reactivity between sulfonamide antibiotics and nonantibiotic sulfonamides. The key patient-specific factor is the prior rash with sulfamethoxazole/trimethoprim, but evidence shows low cross-reactivity with diuretics like hydrochlorothiazide. Clarifying reaction severity and monitoring for rash is the best choice, as absolute contraindication is not supported and benefits may outweigh low risks. Absolute avoidance overstates risk, documenting penicillin allergy is unrelated, and avoiding vitamin D3 is unnecessary. A transferable clinical pearl is that sulfonamide cross-reactivity is rare between antibiotic and nonantibiotic classes due to structural differences. Employ a decision framework: evaluate reaction history, weigh risks versus benefits, and plan for close monitoring post-initiation.
  9. A 67-year-old male (weight 84 kg) is establishing care at your community pharmacy after moving. He brings a pill organizer but no medication list and is unsure of strengths; he reports histories of heart failure with reduced ejection fraction, atrial fibrillation, type 2 diabetes, and chronic kidney disease stage 3. Recent labs from an outside clinic: serum creatinine 1.8 mg/dL, estimated glomerular filtration rate 38 mL/min/1.73 m2^2, alanine aminotransferase 28 U/L, aspartate aminotransferase 25 U/L, hemoglobin A1c 7.9%, and international normalized ratio 1.1. Allergies: "penicillin—hives as a kid." He recalls taking "a blood thinner," "a water pill," "a heart pill," metformin 1000 mg twice daily, and insulin glargine 20 units nightly. What is the most important step in verifying the patient's medication history?
    Answer: Contact the patient's previous pharmacy and prescribers to obtain a fill history and current active prescriptions (drug, strength, directions, last fill date) This question tests the pharmacist's role in accurate medication reconciliation for a new patient with incomplete medication history. The key patient-specific factor is the vague recall of medications, including an unspecified 'blood thinner' with an INR of 1.1, alongside comorbidities like atrial fibrillation and chronic kidney disease. Contacting the previous pharmacy and prescribers is the best choice because it provides objective fill history and active prescriptions to ensure safe dispensing and avoid assumptions. Recommending aspirin is inappropriate without confirming the anticoagulant, assuming warfarin ignores other possibilities like direct oral anticoagulants, and documenting only named medications or deferring risks incomplete reconciliation. A transferable clinical pearl is that medication reconciliation should prioritize external verification sources like pharmacies or electronic records when patient recall is unreliable. Pharmacists can use a systematic framework: ask open-ended questions, review available labs, and cross-verify with historical data to build an accurate profile.
  10. A 66-year-old female (weight 72 kg) is picking up a new prescription for clarithromycin 500 mg twice daily for sinusitis. Current medications: simvastatin 40 mg nightly, amlodipine 5 mg daily, and levothyroxine 100 mcg daily. Medical history: hyperlipidemia, hypertension, hypothyroidism. Labs: serum creatinine 0.9 mg/dL, alanine aminotransferase 30 U/L, aspartate aminotransferase 28 U/L. Allergies: "erythromycin—stomach cramps." Which medication requires verification due to potential interaction?
    Answer: Simvastatin 40 mg nightly This question tests the recognition of drug interactions with macrolide antibiotics like clarithromycin. The key patient-specific factor is simvastatin use with clarithromycin, as clarithromycin inhibits CYP3A4, increasing simvastatin levels and rhabdomyolysis risk. Simvastatin requires verification to consider dose reduction or holding during therapy. Levothyroxine, amlodipine, and fluticasone do not have significant interactions with clarithromycin. A transferable clinical pearl is that high-dose simvastatin should be avoided with strong CYP3A4 inhibitors. Use a framework: check for CYP interactions, assess statin intensity, and recommend temporary adjustments.
  11. A 79-year-old female (weight 55 kg) is being discharged after hospitalization for pneumonia and acute kidney injury that has improved. Discharge labs: serum creatinine 1.4 mg/dL (baseline 1.0), alanine aminotransferase 30 U/L, aspartate aminotransferase 27 U/L, and hemoglobin A1c 6.8%. Medical history includes hypertension, osteoarthritis, and gastroesophageal reflux disease. Home medications prior to admission: lisinopril 20 mg daily, hydrochlorothiazide 25 mg daily, ibuprofen 600 mg three times daily as needed, and omeprazole 20 mg daily; discharge medications include azithromycin 500 mg day 1 then 250 mg daily days 2–5, and "resume home meds." Allergy: "naproxen—stomach upset." What counseling point is crucial based on the patient's medication history?
    Answer: Avoid using ibuprofen regularly while kidney function is still recovering and discuss safer pain options with the prescriber This question tests counseling on medication safety post-hospitalization, focusing on drug interactions and contraindications in recovery. The key patient-specific factor is the recent acute kidney injury with elevated serum creatinine and chronic ibuprofen use, which can further impair renal function. Advising to avoid regular ibuprofen and discuss alternatives is the best choice to protect recovering kidneys and prevent worsening. Stopping omeprazole is unnecessary as it does not inactivate azithromycin, taking azithromycin with grapefruit juice may alter absorption unpredictably, and doubling hydrochlorothiazide risks electrolyte imbalances without indication. A transferable clinical pearl is that NSAIDs like ibuprofen should be used cautiously in patients with renal impairment due to prostaglandin inhibition. Employ a framework: review discharge labs, identify high-risk home medications, and prioritize counseling on modifiable risks to optimize outcomes.
  12. A 52-year-old man (weight 102 kg) with type 2 diabetes presents for a refill and reports his blood glucose has been "running high" for the past month. Current medications on file: insulin glargine 30 units subcutaneously nightly, insulin aspart 8 units subcutaneously with meals, metformin extended-release 1,000 mg by mouth nightly, and lisinopril 10 mg by mouth daily; he admits he often skips mealtime insulin when eating out and sometimes forgets his basal insulin on weekends. Pertinent labs: A1c 9.2% (high), SCr 1.0 mg/dL. Documented allergies: none. What counseling point is crucial based on the patient's medication history?
    Answer: Emphasize consistent administration of basal insulin and strategies to avoid missed bolus doses (e.g., carrying pens, setting reminders) to improve glycemic control This question tests diabetes medication adherence counseling and its impact on glycemic control. The key patient-specific factor is poor adherence to both basal and bolus insulin regimens resulting in an A1c of 9.2%. Emphasizing consistent insulin administration with adherence strategies (choice B) is the BEST answer because the patient's hyperglycemia is primarily due to missed doses rather than inadequate dosing, and practical solutions (carrying pens, reminders) address the root cause. Stopping insulin aspart (choice A) would worsen postprandial control. Doubling glargine without monitoring (choice C) is dangerous and doesn't address missed bolus doses. Taking aspart at bedtime (choice D) is inappropriate as rapid-acting insulin should coincide with meals. The clinical pearl is that before adjusting insulin doses for poor control, adherence must be assessed and optimized, as missed doses are a common cause of hyperglycemia that won't improve with dose increases alone.
  13. A 63-year-old male (weight 77 kg) with chronic obstructive pulmonary disease is admitted and now being discharged. Discharge medications include tiotropium inhaler 2 inhalations daily, albuterol inhaler 2 puffs every 4–6 hours as needed, prednisone 40 mg daily for 5 days, and azithromycin 500 mg day 1 then 250 mg daily days 2–5. He reports home medications as "a blood pressure pill" and "a cholesterol pill," but the discharge summary lists lisinopril 20 mg daily and atorvastatin 40 mg nightly without confirming last fill. Labs: serum creatinine 1.1 mg/dL, alanine aminotransferase 32 U/L, aspartate aminotransferase 29 U/L. Allergies: "none known." What is the most important step in verifying the patient's medication history?
    Answer: Verify lisinopril and atorvastatin with the patient's outpatient pharmacy fill history and confirm the patient's actual home doses and adherence before labeling them as 'resume' This question tests the verification of home medications during transitions of care to ensure accurate reconciliation. The key patient-specific factor is the vague patient recall of 'a blood pressure pill' and 'a cholesterol pill' with unconfirmed doses in the discharge summary. Verifying with the outpatient pharmacy is the best choice to confirm actual doses and adherence, preventing errors like drug interactions with azithromycin and atorvastatin. Discontinuing atorvastatin ignores short-term interaction management, assuming accuracy risks dispensing errors, and removing medications delays care. A transferable clinical pearl is that discharge summaries often contain inaccuracies; always cross-verify with primary sources. Use a framework: compare patient report, summary, and fill history, then reconcile discrepancies for safe dispensing.
  14. A 68-year-old female (weight 63 kg) is discharged after a transient ischemic attack with new prescriptions for clopidogrel 75 mg daily and omeprazole 20 mg daily for gastroprotection. Home medications include atorvastatin 40 mg nightly and sertraline 50 mg daily. Labs: serum creatinine 1.0 mg/dL, alanine aminotransferase 28 U/L, aspartate aminotransferase 26 U/L. Allergies: "none." Which medication requires verification due to potential interaction?
    Answer: Omeprazole 20 mg daily This question tests the identification of pharmacokinetic interactions affecting antiplatelet therapy. The key patient-specific factor is omeprazole use with clopidogrel, as omeprazole inhibits CYP2C19, reducing clopidogrel activation and efficacy post-TIA. Omeprazole requires verification to consider alternatives like pantoprazole with less interaction. Atorvastatin, sertraline, and clopidogrel itself are not the interacting pair here. A transferable clinical pearl is that certain PPIs like omeprazole diminish clopidogrel's antiplatelet effects. Employ a framework: screen for CYP2C19 inhibitors, evaluate alternatives, and recommend switches for high-risk patients.
  15. A 58-year-old male (weight 92 kg) requests a comprehensive medication review due to dizziness and falls. Medical history: type 2 diabetes, hypertension, benign prostatic hyperplasia, chronic low back pain, and insomnia. Current medications: metformin 1000 mg twice daily, glipizide 10 mg twice daily, lisinopril 40 mg daily, amlodipine 10 mg daily, tamsulosin 0.4 mg nightly, cyclobenzaprine 10 mg three times daily as needed, and zolpidem 10 mg nightly. Labs: serum creatinine 1.0 mg/dL, alanine aminotransferase 35 U/L, aspartate aminotransferase 30 U/L, hemoglobin A1c 6.4%. Allergies: "codeine—nausea." Which medication on the list is most likely causing the patient's symptoms?
    Answer: Zolpidem 10 mg nightly This question tests the identification of medications contributing to adverse effects like dizziness and falls in older adults. The key patient-specific factor is the use of zolpidem 10 mg nightly for insomnia, which can cause central nervous system depression and increase fall risk, especially in a patient with multiple comorbidities. Zolpidem is the most likely culprit because it is a sedative-hypnotic associated with dizziness and impaired balance. Metformin, lisinopril, and amlodipine are less likely as they do not typically cause these symptoms at stable doses with controlled conditions. A transferable clinical pearl is that sedative medications like zolpidem should be deprescribed in older adults per Beers Criteria to minimize fall risk. Use a decision framework: evaluate symptoms against medication side effect profiles, consider polypharmacy, and recommend deprescribing high-risk agents.
  16. A 59-year-old male (weight 90 kg) with chronic back pain reports new constipation and drowsiness over the last week. Current medications: oxycodone immediate-release 10 mg every 4 hours as needed (using 5–6 doses/day), gabapentin 600 mg three times daily, cyclobenzaprine 10 mg nightly as needed, and lisinopril 20 mg daily. Labs: serum creatinine 1.0 mg/dL, alanine aminotransferase 33 U/L, aspartate aminotransferase 30 U/L. Allergies: "hydrocodone—itching." Which medication on the list is most likely causing the patient's symptoms?
    Answer: Oxycodone immediate-release 10 mg every 4 hours as needed This question tests the identification of opioid-related adverse effects in chronic pain management. The key patient-specific factor is the high daily use of immediate-release oxycodone, which commonly causes constipation and drowsiness through mu-receptor agonism. Oxycodone is the most likely cause due to its frequency and dose contributing to these classic opioid side effects. Lisinopril, gabapentin, and cyclobenzaprine are less associated with new-onset constipation. A transferable clinical pearl is that opioids require proactive bowel regimens to prevent constipation. Apply a decision framework: correlate symptom onset with medication changes, evaluate usage patterns, and suggest mitigation strategies.
  17. A 59-year-old man (weight 95 kg) requests a comprehensive medication review due to dizziness and near falls. Medical history includes type 2 diabetes, hypertension, benign prostatic hyperplasia, and chronic low back pain. Current medications: metformin 1,000 mg by mouth twice daily, glipizide 10 mg by mouth twice daily, lisinopril 20 mg by mouth daily, hydrochlorothiazide 25 mg by mouth daily, tamsulosin 0.4 mg by mouth nightly, gabapentin 600 mg by mouth three times daily, and cyclobenzaprine 10 mg by mouth three times daily as needed (using daily). Pertinent labs: A1c 6.4%, SCr 1.0 mg/dL. Documented allergies: ibuprofen (heartburn). Which medication on the list is most likely causing the patient's symptoms?
    Answer: Cyclobenzaprine 10 mg by mouth three times daily as needed (using daily) This question tests identification of medication-related causes of dizziness and fall risk in an older adult. The key patient-specific factor is daily use of cyclobenzaprine, a centrally-acting muscle relaxant, in a 59-year-old patient experiencing dizziness and near falls. Cyclobenzaprine (choice A) is the BEST answer because it causes significant CNS depression, sedation, and anticholinergic effects that increase fall risk, especially with regular use and in combination with gabapentin. Metformin (choice B) rarely causes dizziness unless causing hypoglycemia, which is unlikely with an A1c of 6.4%. Lisinopril (choice C) and metoprolol (choice D) can cause orthostatic hypotension but are less likely culprits given stable use. The clinical pearl is that muscle relaxants like cyclobenzaprine are high-risk medications in older adults (Beers Criteria) and should be used sparingly, if at all, due to sedation and fall risk, particularly when combined with other CNS depressants.
  18. A 34-year-old woman (weight 64 kg) presents to the pharmacy with hives and lip swelling that started 2 hours after taking her first dose of trimethoprim-sulfamethoxazole double strength 1 tablet by mouth twice daily for a urinary tract infection. Current medications include ethinyl estradiol/levonorgestrel 1 tablet by mouth daily and sertraline 50 mg by mouth daily. Pertinent labs: SCr 0.8 mg/dL; aspartate aminotransferase (AST) 22 units/L. Documented allergies: "sulfa—unknown reaction" (reported by her mother). Which action should the pharmacist take regarding the reported allergy?
    Answer: Advise the patient to stop trimethoprim-sulfamethoxazole and seek urgent evaluation for possible anaphylaxis; document sulfonamide antibiotic allergy with reaction details This question tests recognition and management of a potential anaphylactic reaction to sulfonamide antibiotics. The key patient-specific factor is the development of hives and lip swelling (angioedema) within 2 hours of trimethoprim-sulfamethoxazole administration in a patient with a documented but unclear sulfa allergy history. Advising immediate discontinuation and urgent evaluation (choice A) is the BEST answer because these symptoms suggest a type I hypersensitivity reaction that could progress to anaphylaxis. Continuing the medication with diphenhydramine (choice B) is dangerous as antihistamines won't prevent anaphylaxis progression. Switching to another sulfonamide (choice C) is contraindicated due to cross-reactivity risk. Documenting as penicillin allergy (choice D) is incorrect and would create inaccurate allergy documentation. The clinical pearl is that any signs of angioedema (lip/tongue swelling) with medication exposure require immediate discontinuation and emergency evaluation, as this can rapidly progress to airway compromise.
  19. A 45-year-old woman (weight 70 kg) with major depressive disorder and migraines asks whether she can start an over-the-counter "cold and flu" product for cough and congestion. Current medications: sertraline 100 mg by mouth daily, sumatriptan 50 mg by mouth as needed for migraine (uses 1–2 doses/week), and amlodipine 5 mg by mouth daily. Pertinent labs: SCr 0.9 mg/dL, AST/ALT within normal limits. Documented allergies: none. Which medication requires verification due to potential interaction?
    Answer: Dextromethorphan-containing cough suppressant due to risk of serotonin syndrome with sertraline This question tests recognition of serotonin syndrome risk with common over-the-counter cold products. The key patient-specific factor is concurrent use of sertraline (an SSRI) with potential exposure to dextromethorphan in cold/flu products. Dextromethorphan-containing products (choice A) require verification as the BEST answer because dextromethorphan has serotonergic activity and can precipitate serotonin syndrome when combined with SSRIs like sertraline. Guaifenesin (choice B) doesn't cause QT prolongation or interact with sertraline. Saline nasal spray (choice C) has no systemic effects or drug interactions. Acetaminophen (choice D) doesn't affect sumatriptan efficacy. The clinical pearl is that many OTC cold/flu products contain dextromethorphan, which can cause serotonin syndrome with SSRIs, SNRIs, or MAOIs; patients on serotonergic medications should use dextromethorphan-free formulations.
  20. A 22-year-old female (weight 58 kg) presents with nausea, tremor, and sweating after her prescriber increased sertraline from 50 mg to 100 mg daily yesterday. She also started an OTC cold product containing dextromethorphan and takes sumatriptan 50 mg as needed for migraines (last dose today). Medical history: depression and migraines. Labs: serum creatinine 0.8 mg/dL, alanine aminotransferase 19 U/L, aspartate aminotransferase 18 U/L. Allergies: none. Which medication requires verification due to potential interaction?
    Answer: Dextromethorphan-containing OTC cold product This question tests the detection of serotonergic drug interactions leading to serotonin syndrome. The key patient-specific factor is the recent sertraline dose increase combined with dextromethorphan and sumatriptan, which can elevate serotonin levels causing nausea, tremor, and sweating. The dextromethorphan-containing product requires verification as it inhibits serotonin reuptake, heightening syndrome risk. Acetaminophen, loratadine, and calcium carbonate do not contribute to serotonergic effects. A transferable clinical pearl is that combining multiple serotonergic agents, including OTCs, necessitates monitoring for syndrome symptoms. Use a framework: list serotonergic medications, assess cumulative risk, and recommend discontinuation of nonessential contributors.

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