PH is a 67 yo F with a PMH of CKD (baseline SCr 2.0 mg/dL which is same today), atrial fibrillation, diabetes mellitus, and hypertension who presents with facial drooping, left sided weakness, and slurred speech. Last known well time was 2 hours ago. The decision to administer tPA has been made with pharmacy consulted to dose. How much tPA should the patient receive and how should it be administered?

Ht: 5’4”, Wt: 100 kg 

A.      100 mg: 10 mg bolus followed by a 90 mg infusion over 1 hour

B.      90 mg: 9 mg bolus followed by an 81 mg infusion over 1 hour

C.      9 mg: 1 mg bolus followed by a 9 mg infusion over 1 hour

D.      10 mg: 1 mg bolus followed by a 9 mg infusion over 1 hour

Answer and Rationale:

The correct answer is B. How many calculations have you done in your rotation year? Chances are you haven't done many outside of possibly pharmacokinetics or TPN. Many students are rusty when it comes to calculations and is definitely an area of importance for the exam. For this question, tPA is dosed 0.9 mg/kg with a maximum dose of 90 mg. 10 % of that dose is infused as a bolus over 1 minute. The remaining 90% is infused over 1 hour. Answer A is incorrect because it exceeds the maximum dose. Answers C and D are incorrect because they are below 0.9 mg/kg. Additionally, knowing absolute contraindications is key to prevent a patient from having a life threatening bleed from tPA such as the patient receiving active anticoagulation.

Spend some time working through calculation problems to remove the rust and improve your chances for scoring well on the exam.

See everyone next week. Can you believe it is March...