Drug Shortages And Biosimilars - NAPLEX

1. A 66-year-old man (weight 79 kg) with metastatic colorectal cancer is receiving bevacizumab (Avastin) plus chemotherapy. The oncology clinic plans to switch to bevacizumab-awwb (Mvasi). Current medications: bevacizumab as above, fluorouracil per protocol, dexamethasone premedication per protocol. What counseling point is crucial when switching to a biosimilar?
   Answer: The biosimilar is expected to have no clinically meaningful differences in safety and effectiveness, but the name/manufacturer may differ for tracking This question tests counseling for switching to a bevacizumab biosimilar in metastatic colorectal cancer. The key patient-specific factor is ongoing therapy with reference bevacizumab plus chemotherapy, requiring reassurance on equivalence. Stating that the biosimilar is expected to have no clinically meaningful differences in safety and effectiveness, but the name/manufacturer may differ for tracking, is crucial because it addresses common concerns while emphasizing pharmacovigilance. Requiring more frequent dosing is false; stopping chemotherapy is harmful; biosimilars are FDA-regulated with adverse event reporting. Recommending not substituting botulinum is unrelated to oncology. A transferable pearl is to highlight biosimilar rigor in approval, encouraging reporting of any changes post-switch. Pharmacists should use product-specific identifiers in records for traceability.
2. A 63-year-old man (weight 84 kg) with type 2 diabetes and obesity is prescribed semaglutide (Ozempic) 0.5 mg subcutaneously once weekly, but the product is unavailable due to a shortage. Current medications include metformin extended-release 1000 mg by mouth twice daily and empagliflozin 25 mg daily; most recent hemoglobin A1c is 8.2%. Medical history includes type 2 diabetes, hypertension, and hyperlipidemia; triglycerides are 140 mg/dL. Which therapeutic alternative is most appropriate for this patient during the drug shortage?
   Answer: Start dulaglutide 0.75 mg subcutaneously once weekly and titrate as tolerated This question tests knowledge of GLP-1 receptor agonist substitution during drug shortages in type 2 diabetes management. The key patient-specific factor is the need for a GLP-1 receptor agonist to improve glycemic control (A1c 8.2%) in a patient with obesity already on dual therapy. Dulaglutide 0.75 mg weekly is the most appropriate alternative as it provides once-weekly GLP-1 agonist therapy similar to semaglutide with proven cardiovascular benefits. Sitagliptin is a DPP-4 inhibitor, not a GLP-1 agonist, and works through a different mechanism with less A1c reduction and no weight loss benefit. Exenatide immediate-release is dosed twice daily (not weekly as stated), making the option incorrect. Liraglutide 3 mg is the obesity treatment dose, not the diabetes dose (which is maximum 1.8 mg daily). When semaglutide is unavailable, other once-weekly GLP-1 agonists like dulaglutide provide similar glycemic and weight benefits with convenient dosing.
3. A 62-year-old man (weight 84 kg) presents to the emergency department with fever, productive cough, and shortness of breath and is being admitted for community-acquired pneumonia requiring intravenous therapy. Medical history includes type 2 diabetes and chronic kidney disease stage 3 (serum creatinine 1.8 mg/dL; estimated creatinine clearance 45 mL/min). Current medications: metformin 1000 mg by mouth twice daily, lisinopril 20 mg by mouth daily, atorvastatin 40 mg by mouth nightly. The prescriber orders ceftriaxone 1 g intravenously every 24 hours plus azithromycin 500 mg intravenously daily, but ceftriaxone is on shortage at your hospital. Which therapeutic alternative is most appropriate for this patient during the drug shortage?
   Answer: Ampicillin/sulbactam 3 g intravenously every 6 hours plus azithromycin 500 mg intravenously daily This question tests the management of community-acquired pneumonia (CAP) during a ceftriaxone shortage, focusing on appropriate intravenous antibiotic alternatives per guidelines. The key patient-specific factors are type 2 diabetes, chronic kidney disease stage 3 with creatinine clearance of 45 mL/min, and the need for inpatient IV therapy. Ampicillin/sulbactam 3 g IV every 6 hours plus azithromycin 500 mg IV daily is the best choice because it provides broad-spectrum coverage similar to ceftriaxone plus azithromycin, is guideline-recommended for non-ICU CAP, and does not require renal dose adjustment for this creatinine clearance. Cefepime plus azithromycin is suboptimal as cefepime is typically reserved for hospital-acquired pneumonia and requires renal adjustment; ertapenem monotherapy lacks atypical coverage and is not first-line for CAP; ciprofloxacin monotherapy is inappropriate for severe CAP requiring IV therapy and has limited pneumococcal activity. Prednisone 40 mg orally daily for 5 days is incorrect as it addresses a different shortage scenario unrelated to antibiotics. A clinical pearl is that during beta-lactam shortages, prioritize alternatives with similar spectra and adjust for renal function to avoid toxicity. Pharmacists should collaborate with prescribers to select evidence-based regimens and monitor for efficacy.
4. A 45-year-old man (weight 88 kg) with rheumatoid arthritis is stable on adalimumab (Humira) 40 mg subcutaneously every 2 weeks plus methotrexate 15 mg by mouth weekly and folic acid 1 mg daily. His insurer now prefers the adalimumab biosimilar adalimumab-adbm, and the prescriber wrote "adalimumab-adbm 40 mg every 2 weeks" without specifying "interchangeable." Medical history includes rheumatoid arthritis and latent tuberculosis treated in the past; he has no current infection symptoms. What is the best approach to substituting a biosimilar for this patient's medication?
   Answer: Dispense adalimumab-adbm in place of Humira only if the biosimilar is designated as interchangeable under state law; otherwise contact the prescriber for authorization This question tests understanding of biosimilar substitution regulations and the distinction between biosimilar and interchangeable products. The key regulatory factor is that biosimilars require specific FDA designation as "interchangeable" to be automatically substituted at the pharmacy level without prescriber authorization. The correct approach is to dispense adalimumab-adbm only if it has interchangeability designation and state law permits substitution; otherwise, prescriber authorization is required. Automatically substituting any biosimilar is incorrect because not all biosimilars are designated as interchangeable - they must meet additional FDA requirements demonstrating they can be switched back and forth with the reference product. Substituting a different TNF inhibitor like infliximab-dyyb or etanercept represents a therapeutic change requiring prescriber approval, not a simple substitution. The clinical pearl is that biosimilars without interchangeability designation require prescriber authorization before dispensing, even if they are the same active ingredient as the reference product.
5. A 74-year-old woman (weight 58 kg) is admitted for acute decompensated heart failure with reduced ejection fraction (left ventricular ejection fraction 30%). She is being transitioned from intravenous diuresis to oral guideline-directed therapy. Medical history: heart failure, hypertension, hyperlipidemia. Current medications: furosemide 40 mg by mouth daily, metoprolol succinate 50 mg by mouth daily, spironolactone 25 mg by mouth daily, atorvastatin 20 mg by mouth nightly. The team wants to start sacubitril/valsartan, but it is non-formulary due to a temporary shortage; the formulary has valsartan and enalapril. Which action should the pharmacist take regarding this non-formulary request?
   Answer: Recommend starting enalapril 10 mg by mouth twice daily and re-evaluate for sacubitril/valsartan once available This question tests the management of heart failure with reduced ejection fraction (HFrEF) during a sacubitril/valsartan shortage, focusing on guideline-directed medical therapy alternatives. The key patient-specific factor is acute decompensated HFrEF with LVEF 30%, requiring initiation of renin-angiotensin system inhibition. Recommending enalapril 10 mg orally twice daily and re-evaluating for sacubitril/valsartan once available is the best choice because enalapril is a formulary ACE inhibitor that provides neurohormonal blockade, aligning with guidelines as an alternative to ARNI. Valsartan plus aliskiren is contraindicated due to risk of hyperkalemia and renal impairment; holding therapy delays essential treatment; switching to carvedilol without RAAS inhibition omits a key pillar of therapy. Administering two standard-dose vaccines is unrelated to heart failure management. A clinical pearl is to prioritize available evidence-based therapies like ACEIs or ARBs during ARNI shortages to optimize outcomes. Use a stepwise approach: stabilize the patient, then reassess for preferred agents when supply returns.
6. A 67-year-old woman (weight 72 kg) is being discharged after a non–ST-elevation myocardial infarction and is prescribed ticagrelor 90 mg by mouth twice daily plus aspirin 81 mg daily; however, ticagrelor is on national backorder at the outpatient pharmacy. Her current medications include aspirin 81 mg daily, atorvastatin 80 mg nightly, metoprolol succinate 50 mg daily, and lisinopril 10 mg daily. Medical history includes coronary artery disease, hypertension, and hyperlipidemia; she has no history of stroke/transient ischemic attack and no active bleeding. Which therapeutic alternative is most appropriate for this patient during the drug shortage?
   Answer: Clopidogrel 75 mg by mouth daily after a 300–600 mg loading dose, then continue with aspirin This question tests knowledge of appropriate P2Y12 inhibitor substitution during drug shortages in acute coronary syndrome management. The key patient-specific factor is that this 67-year-old woman has experienced a non-ST-elevation myocardial infarction (NSTEMI) and requires dual antiplatelet therapy with aspirin plus a P2Y12 inhibitor. Clopidogrel 75 mg daily after a 300-600 mg loading dose is the most appropriate alternative because it provides effective P2Y12 inhibition for secondary prevention after NSTEMI and is widely available. Prasugrel is contraindicated in patients ≥75 years old due to increased bleeding risk and should not be used in this 67-year-old patient. Dipyridamole/aspirin is indicated for stroke prevention, not post-MI management. Warfarin plus aspirin would significantly increase bleeding risk without additional benefit in NSTEMI without other indications for anticoagulation. When ticagrelor is unavailable, clopidogrel remains the standard P2Y12 inhibitor alternative for post-ACS management, with similar efficacy for preventing recurrent cardiovascular events.
7. A 6-year-old boy (weight 20 kg) is in clinic for routine immunizations. The clinic has a temporary shortage of inactivated poliovirus vaccine (IPV) and cannot administer it today. He previously received IPV at 2 months and 4 months but missed the 6-month dose; he is otherwise healthy and takes no medications. Which action should the pharmacist take regarding this vaccine shortage impacting the recommended immunization schedule?
   Answer: Defer IPV and schedule the next IPV dose as soon as it becomes available; do not restart the series This question tests understanding of vaccine shortage management and the principle of not restarting interrupted vaccine series. The key concept is that vaccine series do not need to be restarted when doses are delayed due to shortages or other factors. The correct action is to defer the IPV dose and administer it as soon as available without restarting the entire series, as vaccines produce immune memory that persists despite delays. Oral poliovirus vaccine (OPV) is not used in the United States due to rare risk of vaccine-associated paralytic poliomyelitis. Restarting the series would unnecessarily delay protection and waste doses. Substituting a different vaccine like meningococcal conjugate cannot replace IPV as they protect against different diseases. The clinical principle is that interrupted vaccine series should be continued from where they left off, not restarted, regardless of the time elapsed since the previous dose.
8. A 48-year-old woman (weight 64 kg) is admitted for methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia. Medical history: none significant. Current medications: none. The prescriber orders nafcillin 2 g intravenously every 4 hours, but nafcillin is unavailable due to shortage; cefazolin is available. Which therapeutic alternative is most appropriate for this patient during the drug shortage?
   Answer: Cefazolin 2 g intravenously every 8 hours This question tests therapeutic alternatives for methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia during a nafcillin shortage. The key patient-specific factor is uncomplicated MSSA bacteremia requiring anti-staphylococcal beta-lactam therapy. Cefazolin 2 g IV every 8 hours is the best choice because it is guideline-recommended as an effective alternative to nafcillin for MSSA, with convenient dosing and good tolerability. Vancomycin is reserved for MRSA or allergy; ceftriaxone has higher failure rates in bacteremia; aztreonam lacks gram-positive coverage. Whether the biosimilar is interchangeable is unrelated to antibiotics. A clinical pearl is to prefer beta-lactams over vancomycin for MSSA due to superior outcomes. During shortages, monitor for treatment response and switch back to preferred agents when available.
9. A 55-year-old woman (weight 66 kg) with rheumatoid arthritis has been stable on adalimumab (Humira) 40 mg subcutaneously every 14 days for 1 year. Current medications: adalimumab as above, methotrexate 15 mg by mouth weekly, folic acid 1 mg by mouth daily, naproxen 250 mg by mouth twice daily as needed. Her insurer now prefers an adalimumab biosimilar and asks the pharmacy to dispense it. What counseling point is crucial when switching to a biosimilar?
   Answer: Use the new product exactly as prescribed, and report any new injection-site reactions or loss of symptom control after the switch This question tests patient counseling principles when switching to an adalimumab biosimilar in rheumatoid arthritis. The key patient-specific factor is stable disease on reference adalimumab with concomitant methotrexate, requiring education on potential subtle differences. Counseling to use the new product as prescribed and report new injection-site reactions or loss of symptom control is crucial because biosimilars are highly similar but switches may rarely affect tolerability or efficacy, necessitating monitoring. Expecting less effectiveness is incorrect as biosimilars demonstrate no clinically meaningful differences; doubling the dose is unnecessary and risky; stopping methotrexate increases flare risk without benefit. Switching to enalapril is unrelated to biologics. A transferable pearl is that biosimilar education should emphasize equivalence while encouraging vigilance for changes, with reporting to healthcare providers. Pharmacists play a key role in building patient confidence through clear communication.
10. A 33-year-old pregnant woman (weight 78 kg, 28 weeks gestation) presents to labor and delivery with preterm premature rupture of membranes and needs group B Streptococcus intrapartum prophylaxis. She reports anaphylaxis to penicillin (throat swelling, hypotension). Current medications: prenatal vitamin daily, ferrous sulfate 325 mg by mouth daily. The usual alternative, clindamycin, is on national shortage and susceptibility results are not available. Which therapeutic alternative is most appropriate for this patient during the drug shortage?
    Answer: Vancomycin 20 mg/kg intravenously every 8 hours (maximum 2 g per dose) until delivery This question tests intrapartum group B Streptococcus (GBS) prophylaxis alternatives during a clindamycin shortage in penicillin-allergic patients. The key patient-specific factor is anaphylaxis to penicillin, preterm premature rupture of membranes at 28 weeks, and lack of clindamycin susceptibility results. Vancomycin 20 mg/kg IV every 8 hours (max 2 g/dose) until delivery is the best choice because guidelines recommend it for high-risk penicillin allergy when clindamycin is unavailable, providing effective GBS coverage. Cefazolin risks cross-reactivity in anaphylaxis; oral amoxicillin is inadequate for intrapartum prophylaxis; azithromycin lacks reliable GBS activity. Dispensing 2 mg tablets is unrelated to antibiotics. A clinical pearl is to use weight-based dosing for vancomycin in pregnancy, monitoring levels if prolonged. During shortages, prioritize guideline alternatives and expedite susceptibility testing when possible.
11. A 58-year-old man (weight 95 kg) with chronic heart failure with reduced ejection fraction (left ventricular ejection fraction 30%) is stable on sacubitril/valsartan 49/51 mg by mouth twice daily, carvedilol 25 mg twice daily, spironolactone 25 mg daily, and furosemide 40 mg daily. Sacubitril/valsartan is currently unavailable due to a wholesaler shortage, and the prescriber asks for a temporary alternative. Baseline blood pressure is 118/72 mm Hg, potassium 4.6 mEq/L (normal 3.5–5.0), serum creatinine 1.0 mg/dL. Which therapeutic alternative is most appropriate for this patient during the drug shortage?
    Answer: Start losartan 50 mg by mouth daily as a temporary substitute and monitor blood pressure, potassium, and renal function This question tests knowledge of appropriate heart failure medication substitution during drug shortages. The key patient-specific factor is that sacubitril/valsartan contains an angiotensin receptor blocker (ARB) component that requires a washout period before starting an ACE inhibitor to prevent angioedema. Losartan 50 mg daily is the most appropriate alternative as it provides continued renin-angiotensin system blockade without the washout period required for ACE inhibitors. Starting lisinopril immediately after sacubitril/valsartan is contraindicated due to increased angioedema risk from overlapping neprilysin inhibition effects. Aliskiren is not recommended in heart failure and would increase hyperkalemia risk when combined with spironolactone. Stopping RAAS inhibition entirely would worsen heart failure outcomes. When sacubitril/valsartan is unavailable, switching to an ARB maintains guideline-directed medical therapy while avoiding the 36-hour washout required before ACE inhibitor initiation.
12. A 45-year-old woman (weight 72 kg) with ulcerative colitis is due for her next vedolizumab infusion. The clinic is considering switching her to a biosimilar, but the only product available is a biosimilar of infliximab. Current medications: vedolizumab 300 mg intravenously every 8 weeks, mesalamine 2.4 g by mouth daily. Which factor should be considered when substituting this biosimilar?
    Answer: A biosimilar can only substitute for its reference product; an infliximab biosimilar cannot replace vedolizumab This question tests the specificity of biosimilar substitution across different reference products in ulcerative colitis. The key patient-specific factor is maintenance on vedolizumab, with an infliximab biosimilar available but not referencing vedolizumab. Stating that a biosimilar can only substitute for its reference product, so an infliximab biosimilar cannot replace vedolizumab, is correct because biosimilars are approved against a specific originator and have different mechanisms (integrin vs. TNF inhibition). Substituting any biologic with similar intervals ignores mechanistic differences; infliximab is not preferred for frequency; biosimilars are not interchangeable across mechanisms. Metoprolol dosing is unrelated to biologics. A transferable pearl is that biosimilar switches must match the reference product to ensure comparable pharmacokinetics and efficacy. Consult prescribers for therapeutic interchanges between different biologics.
13. A 6-month-old infant (female, weight 7.2 kg) presents for routine immunizations. She previously received 2 doses of pneumococcal conjugate vaccine at 2 and 4 months. The clinic is experiencing a shortage of pneumococcal conjugate vaccine (PCV) and only has enough supply for high-risk infants; this patient is healthy with no chronic conditions. Current medications: none. Which action should the pharmacist recommend to manage this patient's immunization schedule given the shortage?
    Answer: Defer the 6-month PCV dose and schedule catch-up PCV when supply returns; continue other routine vaccines on time This question tests the management of pediatric pneumococcal conjugate vaccine (PCV) schedules during a shortage, per ACIP recommendations. The key patient-specific factor is a healthy 6-month-old infant who has received the first two PCV doses, with no high-risk conditions qualifying for prioritized supply. Deferring the 6-month PCV dose and scheduling catch-up when supply returns, while continuing other routine vaccines, is the best approach because ACIP advises delaying doses in low-risk children during shortages without restarting the series. Administering PPSV23 now is inappropriate as it is not indicated for infants under 2 years; restarting the series is unnecessary as interrupted intervals do not invalidate prior doses; substituting meningococcal vaccine does not provide pneumococcal protection. Switching to NPH insulin is unrelated to vaccinations. A transferable pearl is that vaccine shortages require risk-based prioritization, with catch-up dosing upon availability to maintain herd immunity. Pharmacists should track deferred doses and notify patients when supply resumes.
14. A 39-year-old woman (weight 70 kg) with ulcerative colitis is in remission on infliximab (Remicade) 5 mg/kg intravenously every 8 weeks. The infusion center has infliximab originator product unavailable and proposes switching to infliximab-dyyb for the next infusion. Current medications include infliximab, mesalamine 2.4 g daily, and a multivitamin; medical history includes ulcerative colitis and iron-deficiency anemia. What counseling point is crucial when switching to a biosimilar?
    Answer: Explain that the biosimilar is expected to have no clinically meaningful differences in safety and effectiveness, but the product name and lot number should be recorded for pharmacovigilance This question tests understanding of biosimilar counseling points and pharmacovigilance requirements. The key concept is that biosimilars are highly similar to reference products with no clinically meaningful differences in safety and efficacy, but require specific documentation for tracking. The correct counseling emphasizes that the biosimilar is expected to work as effectively as the originator while highlighting the importance of recording the specific product name and lot number for pharmacovigilance purposes. Biosimilars work through the same mechanism as originators and do not require dose adjustments. There is no interaction between mesalamine and infliximab biosimilars. Biosimilars carry the same risk of infusion reactions as originator products. The clinical pearl is that while biosimilars are therapeutically equivalent, accurate documentation of the specific product dispensed is crucial for post-market surveillance and tracking any potential product-specific adverse events.
15. A 52-year-old woman (weight 73 kg) with HER2-positive breast cancer receives trastuzumab (Herceptin) intravenously every 3 weeks as part of maintenance therapy. Current medications: trastuzumab as above, ondansetron 8 mg by mouth as needed, lisinopril 10 mg by mouth daily. The infusion center plans to switch to trastuzumab-dkst (Ogivri). What is the best approach to substituting a biosimilar for this patient's medication?
    Answer: Switch to trastuzumab-dkst at the same mg/kg dose and schedule, ensuring product-specific documentation for pharmacovigilance This question tests the approach to substituting a trastuzumab biosimilar in HER2-positive breast cancer maintenance therapy. The key patient-specific factor is ongoing intravenous trastuzumab therapy, requiring seamless continuation with a highly similar product. Switching to trastuzumab-dkst at the same mg/kg dose and schedule with product-specific documentation is best because biosimilars are approved based on similarity in efficacy, safety, and quality, and documentation aids pharmacovigilance. Switching to bevacizumab is inappropriate as it targets VEGF, not HER2; reducing dose by 50% lacks evidence; biosimilars are allowed for antineoplastics. Recommending prednisone is unrelated to biologics. A transferable pearl is to maintain the reference product's regimen when switching biosimilars, with monitoring for cardiotoxicity in trastuzumab use. Ensure traceability by recording the specific biosimilar name and lot number.
16. A 68-year-old man (weight 76 kg) is admitted with a pulmonary embolism and started on a heparin infusion. The team plans to transition him to warfarin, but warfarin 5 mg tablets are on shortage; 2 mg and 10 mg tablets are available. Medical history: atrial fibrillation, hypertension. Current medications: metoprolol tartrate 50 mg by mouth twice daily, amlodipine 10 mg by mouth daily. The prescriber wants to start warfarin 5 mg by mouth daily. How should the pharmacist manage this patient's therapy given the shortage?
    Answer: Dispense warfarin 2 mg tablets and instruct the patient to take 2 tablets plus half of a 2 mg tablet daily (total 5 mg), with clear written directions This question tests the management of warfarin dosing during a tablet strength shortage, emphasizing safe dispensing to achieve the prescribed dose. The key patient-specific factor is the need for a precise 5 mg daily dose for pulmonary embolism bridging, with available 2 mg and 10 mg tablets. Dispensing 2 mg tablets and instructing to take 2 tablets plus half of a 2 mg tablet daily (total 5 mg) with clear written directions is best because it accurately delivers the dose while minimizing confusion through explicit guidance. Using 10 mg tablets for 1 daily is overdosing; instructing 2.5 tablets without specifying halving may lead to errors; discontinuing anticoagulation risks thrombosis. Expecting less effectiveness is unrelated to warfarin. A clinical pearl is to provide visual aids or pill cutters for split doses during shortages to enhance adherence and safety. Always verify patient understanding and monitor INR closely after changes.
17. A 61-year-old woman (weight 71 kg) with type 2 diabetes is controlled on dulaglutide 1.5 mg subcutaneously once weekly and metformin 1000 mg by mouth twice daily. Dulaglutide is on shortage for at least 1 month; semaglutide injection is available. Medical history: type 2 diabetes, obesity, hypertension. Current medications: dulaglutide 1.5 mg weekly, metformin 1000 mg twice daily, losartan 50 mg by mouth daily. Which therapeutic alternative is most appropriate for this patient during the drug shortage?
    Answer: Start semaglutide 0.25 mg subcutaneously once weekly and titrate per labeling to minimize gastrointestinal adverse effects This question tests GLP-1 receptor agonist alternatives during a dulaglutide shortage in type 2 diabetes. The key patient-specific factor is controlled disease on dulaglutide 1.5 mg weekly, requiring titration to minimize gastrointestinal side effects. Starting semaglutide 0.25 mg subcutaneously weekly and titrating per labeling is best because it allows gradual dose escalation similar to dulaglutide, maintaining glycemic control. Starting at 1 mg risks severe GI intolerance; exenatide IR requires BID dosing, less convenient; stopping GLP-1 and increasing metformin exceeds safe doses. Levalbuterol inhaler is unrelated to diabetes. A clinical pearl is to titrate GLP-1 agonists slowly (e.g., semaglutide: 0.25 mg x4 weeks, then 0.5 mg) to improve tolerability. Monitor A1c and weight, adjusting based on response during shortages.
18. A 72-year-old woman (weight 62 kg) with asthma is scheduled for a high-dose influenza vaccine. The clinic has a shortage of high-dose influenza vaccine but has standard-dose inactivated influenza vaccine available. Medical history: asthma, coronary artery disease. Current medications: budesonide/formoterol inhaler 2 puffs twice daily, albuterol inhaler as needed, aspirin 81 mg by mouth daily. Which action should the pharmacist recommend to manage this immunization challenge given the shortage?
    Answer: Administer standard-dose inactivated influenza vaccine today rather than delaying vaccination This question tests influenza vaccination strategies during a high-dose vaccine shortage in older adults. The key patient-specific factor is age 72 years with asthma and coronary artery disease, benefiting from any timely influenza vaccination. Administering standard-dose inactivated influenza vaccine today rather than delaying is best because ACIP recommends vaccinating with available products during shortages, as some protection is better than none. Deferring until high-dose availability risks exposure; administering two standard doses does not equate to high-dose; live vaccine is contraindicated in older adults and asthma. Meropenem dosing is unrelated to vaccines. A clinical pearl is that timely vaccination outweighs waiting for preferred formulations in high-risk groups. Counsel on revaccination if supply allows, but prioritize initial protection.
19. A 26-year-old woman (weight 58 kg) with Crohn disease receives ustekinumab (Stelara) 90 mg subcutaneously every 8 weeks for maintenance after an intravenous induction dose. She asks whether the pharmacy can substitute "a ustekinumab biosimilar" because her copay is high; the state allows substitution only for products designated as interchangeable. Current medications include ustekinumab, prednisone 5 mg daily (tapering), and vitamin D3 2000 units daily; medical history includes Crohn disease and mild asthma. Which factor should be considered when substituting this biosimilar?
    Answer: Whether the biosimilar has an FDA interchangeability designation (and state law requirements for substitution and prescriber notification) This question tests understanding of biosimilar interchangeability regulations and state-specific substitution requirements. The key regulatory factor is that biosimilar substitution at the pharmacy level requires both FDA interchangeability designation and compliance with state pharmacy laws regarding substitution and prescriber notification. Only biosimilars with specific FDA interchangeability designation can be automatically substituted, and states may have additional requirements for prescriber notification. Not all monoclonal antibody biosimilars can be substituted for each other - they must be biosimilars of the same reference product. Ustekinumab is FDA-approved for Crohn disease, not off-label use. Biosimilar switching does not require dose adjustments as they are highly similar to reference products. The clinical pearl is that pharmacists must verify both federal interchangeability designation and state-specific substitution laws before dispensing a biosimilar in place of a prescribed reference product.
20. A 24-year-old woman (weight 63 kg) with asthma comes to the pharmacy because her albuterol metered-dose inhaler is on backorder. The pharmacy has levalbuterol inhalers in stock. Medical history: asthma. Current medications: albuterol inhaler 2 puffs every 4 to 6 hours as needed, fluticasone inhaler 2 puffs twice daily. Which therapeutic alternative is most appropriate for this patient during the drug shortage?
    Answer: Levalbuterol inhaler 2 puffs every 4 to 6 hours as needed for shortness of breath This question tests rescue inhaler alternatives during an albuterol shortage in asthma. The key patient-specific factor is as-needed use for shortness of breath, requiring a similar short-acting beta-agonist. Levalbuterol inhaler 2 puffs every 4 to 6 hours as needed is the best alternative because it is the active enantiomer of albuterol, providing equivalent bronchodilation with potentially fewer side effects. Salmeterol is long-acting, not for acute relief; fluticasone is a corticosteroid without rescue properties; ipratropium is an anticholinergic, slower onset for acute symptoms. Omeprazole 40 mg is unrelated to asthma. A clinical pearl is to reserve levalbuterol for patients with albuterol intolerance, but use it 1:1 during shortages. Educate on proper inhaler technique and when to seek emergency care.

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