Amlodipine Dispensing Error and Leftover NSAID Request in a CKD Cat
AM is a 4.8 kg, 12-year-old spayed cat with hypertrophic cardiomyopathy and systemic hypertension. The veterinarian prescribes amlodipine 0.625 mg PO every 24 hours. The clinic pharmacy has only 5 mg amlodipine tablets and dispenses 30 tablets with a label reading 'Give 1/4 tablet by mouth once daily.' The owner calls two weeks later: the cat is lethargic and has vomited twice, and the owner admits she has been giving the quarter tablet plus a 'small extra sliver' because the pieces crumble. She also asks whether she can use leftover meloxicam 0.5 mg/mL from her other cat, because AM seems stiff. The cat's most recent creatinine was 2.4 mg/dL (IRIS stage 2), and it is not currently receiving any other medications. The technician must triage the call.
1. Calculate the dose the cat has actually been receiving from the labeled instructions. Identify the dispensing error and outline the immediate nursing and client-communication steps.
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A quarter of a 5 mg tablet is 1.25 mg, not 0.625 mg. The label therefore delivers twice the prescribed dose, and the owner's extra sliver pushes it higher. Vomiting and lethargy are plausible signs of amlodipine overdose: hypotension, weakness, and reflex tachycardia or bradycardia. Do not give another dose. Contact the veterinarian now and check blood pressure, heart rate, and hydration. Hospitalize if systolic blood pressure is below 90 mmHg or the cat is recumbent. There is no specific antidote; treatment is supportive, including IV fluids if hypotensive, monitoring, and antiemetics as directed. Correct the prescription to a 2.5 mg tablet quartered to yield 0.625 mg, or better, a compounded 0.5 mg/mL suspension with a 1.25 mL dose, because quartering tablets is imprecise. Document the dispensing error and have the veterinarian speak with the owner before any new dose is given.
2. How should the technician respond to the request to use the other cat's meloxicam? Explain the specific risks in this cat.
Read the worked answer
Do not authorize use of the other cat's meloxicam. This cat has IRIS stage 2 CKD with a creatinine of 2.4 mg/dL, is hypertensive, and is currently vomiting. All of these increase NSAID risk. Meloxicam can reduce renal perfusion and cause acute kidney injury, especially with dehydration or concurrent ACE inhibitor or angiotensin receptor blocker therapy. There is also no valid veterinarian-client-patient relationship for the other cat and no current examination for this cat. Tell the owner to stop the amlodipine error first and have the veterinarian evaluate pain and renal status. If analgesia is needed, the veterinarian may choose a non-NSAID option such as gabapentin or buprenorphine after examination. Do not dispense from leftover stock, and record the advice given.