Pharmacodynamics & Pharmacokinetics Quiz

Heparin is a commonly used blood thinner and works by increasing antithrombin III activity 1000X, which in turn inhibits thrombin and factor Xa. Heparin is a large molecule with a strong negative charge. Based on these characteristics, match the likely absorption pattern, volume of distribution, and rate of clearance of heparin.

A 21 year old college student presents to the emergency room intoxicated and a blood alcohol level of 0.23 (legal limit 0.08). If 0.015 units is metabolized in the first hour, how many hours would it take to reach the legal limit?

Drug X is a potent blood pressure drug which works through renin-angiotensin inhibition. Drug Y is a competitive antagonist of drug X. What effect would you expect to see on the log-dose curve if both drugs were given to the same patient?

Drug X is a potent blood pressure drug which works through renin-angiotensin inhibition. Drug Y is a competitive antagonist of drug X. If Drug Y bound covalently to the drug receptor site for Drug X how would the resultant log-dose curve change?

A 70 kg male patient on the general medicine ward is being treated for lower extremity cellulitis. He has not shown any improvement in his infective symptoms or redness for last 24 hours with oral amoxicillin-clavulanic acid and he is now tachycardic and febrile with rising white blood cell count. It is decided to switch antibiotics to vancomycin and the loading dose needs to be calculated. The desired plasma concentration is 20mg/L following bolus, knowing that it will take 4 half-lives to reach steady state and can’t wait that long to be in the therapeutic range. The inherent volume of distribution of vancomycin is 1L/kg. What dose of vancomycin should be given?

A researcher is investigating a new chemotherapy for treatment of metastatic triple negative breast cancer named MZ289. In early phase I clinical trials a study of 20 patients showed that 10 patients developed response to the drug at a dose of 200 mg/kg. When titrated to a dose of 400mg/kg, roughly half of all patients developed severe toxicity and had to come off of the drug. What is the therapeutic index of MZ289?

A researcher is investigating a new chemotherapy for treatment of metastatic triple negative breast cancer named MZ289. In early phase I clinical trials a study of 20 patients showed that 10 patients developed response to the drug at a dose of 200 mg/kg. When titrated to a dose of 400mg/kg, roughly half of all patients developed severe toxicity and had to come off of the drug.

A rival drug company is also making a drug with similar mechanism of action as MZ289 for breast cancer which they have named SX981. Their drug has a therapeutic index of 1.2 in their first in human studies. Which is true in a comparison SX981 to MZ289?

A company is designing a new drug that treats schizophrenia. The drug has a large molecular weight, is insoluble in water, and is coated in a microsphere that prevents degradation. When given IM its half-life is roughly 6 days. How long does it take for the drug to reach steady state?

A company is designing a new drug that treats schizophrenia. The drug has a large molecular weight, is insoluble in water, and is coated in a microsphere that prevents degradation. When given IM its half-life is roughly 6 days. Calculate how long it will take for the drug to reach steady state. Based on this calculation, what is a potential pitfall of this new drug when used clinically?