Kinetics Exam 2 Clickers
A blood sample is obtained from a patient on a drug to determine the fu. After centrifugation, plasma is obtained and subjected to ultrafiltration. The concentration in plasma is found to be 3.6 mg/L while that in the ultrafiltrate is 1.2 mg/L. From this data, determine the fu for this experimental agent.
0.3
How is r related to the fraction of drug bound (fu), a term that is often of clinical interest?
r is the ratio of the numer of moles of drug bound to the number of moles of albumin. r determines the fraction of drug binding sites that are occupied. fu is the fraction of drug which is free in the plasma The value of fu is often assumed to be fixed However, fu may change as drug concentration increases, especially with drugs that have therapeutic concentrations close to Kd.
Assume a drug for which the M/p is 5 and the average maternal plasma concentration is 0.1 mg/L. Assuming the child averages 750 mL of breast milk per day, which is the approximate daily dose of the drug received by the nursing infant?
0.375 mg
A solution of verapamil is administered to the portal vein of the isolated perfused liver of a rate at a concentration of 8mg/L. After 5 minutes, the concentration that is measured at the hepatic vein is 2.57mg/L. What is the hepatic extraction rate of verapamil in this model?
0.68
What will be the rate of reabsorption if the rate of filtration is 3mL/sec, rate of secretion is 0.5mL/sec, and the rate of excretion is 2mL/sec for a particular drug?
1.5 mL/sec
TJ is a 55 year old 70kg male presenting to the emergency department with acute ventricular tachycardia. The attending physican elects to initiate therapy with lidocaine ti treat this. Lidocaine is to be administered as an IV with goal of achieving initial concentration of 2 mg/L. The ED pharmacist indicates the average VD for lidocaine is 1 L/kg. Based on this, she is able to calculate the initital dose needed to achieve this target concentration. Find this initial dose.
140 mg
A given drug is completely absorbed by extensively metabolized by the intestinal epithelium (91%) followed by extensive hepatic elimination (71%). What is expected overall oral bioavaiablilty? (math)
2.6%
A drug has a total clearance of 300mL/min and 20% of the drug is eliminated as such by the kidney. On the assumption that only the liver and kidney are involved in this elimination process, which of the following will be hepatic clearance of that drug in mL/min?
240 mL/min
What will be the elimination rate if the clearance is 120 mL/min and drug concentration is 0.5mg/mL?
60mg/min
A girl with age 25 has height 240cm, weight 55kg, serum creatine of 0.8 mg will have _______________ creatine clearance.
93.3 mL/min
Drugs least likely to diffuse across membranes A) protein bound drugs B) uncharged drugs C) weak acid drugs D) weak base drugs
A
Nitroglycerine is administered by which route A) sublingual B) inhalation C) IV D) ectopic
A
Only free drugs can act on target sites and can be eliminated? A) true B) false
A
Roots of administation that avoid first pass hepatic effects A) sublingual B) oral C) rectal suppositories D) none of the above
A
The volume of distribution for a drug highly bound in peripheral tissues would be? A) high B) low C) unchanged D) Zero
A
Which of the following is not correct about properties of carrier mediated drug transport? A) non saturable B) active transport C) energy requiring D) similarity to natural ligand
A
The most likely site of absorption of a controlled release form of an oral drug A) stomach B) large intestine C) liver D) lymphatic system
B
Most important factor that affects a drugs volume of distribution A) patients gender B) extent of plasma-protein binding C) kidney disease D) drug pKa
B
The aqueous solubility of a weak base in an intestinal perfusion study, the drug was not absorbed beyond the jejunum. which of the following would be the correct strategy to improve drug absorption from the intestinal tract? A) give the drug as a suspension and recommend that the suspension be taken on an empty stomach B) give the drug as a hydrochloride salt C) give the drug with milk D) give the drug as a suppository
B
A patient requires a high dose of a new antihypertensive medication because the new medication has a significant first-pass effect. What does this mean? A) the medication must pass through the patients bloodstream several times to generate a therapeutic effect B) the medication is extensively metabolized C) the medication is ineffective followung the first dose and increasingly effective with each subsequent dose
B
What is the driving force for passive diffusion? A) endocytosis B) concentration and electrochemical gradient C) volume disribution D) liver metabolism
B
Most of the oral drug absorption occurs in A) ileum B) liver C) duodenum D) colon
C
The major driving force in drug movement in aqueous diffusion model A) active transport - energy requiring B) facilitated diffusion C) drug concentration D) number of transporters
C
The pKa of a weak acid drug is 6.5. If the pH pf the medium is 5.5, the drug will be A) negatively charged B) positively charged C) mainly neutral
C
Which of the following does albumin have the strongest affinity for? A) anionic drugs B) hydrophilic drugs C) hydrophobic drugs
C
Which of the following statements is true regarding an acidic drug with a pKa of 4? A) the drug is more soluble in the stomach when food is present B) the drug is slowly absorbed from the stomach than duodenum C) the drug is more soluble when dissociated
C
Oral administration advantage A) drug taken orally may be destroyed by gastric acidicty B) drug taken orally may be metabolized by gastrointestinal flora C) drug taken orally may be inconsistently absorbed due to the presence of food D) none of the above E) all of the above
D
What is the fraction of uncharged drugs reaching systemic circulation? A) elimination B) volume distribution C) metabolism D) bioavailability
D
What is total systemic clearance? A) sum of clearance from the kidney B) Sum of clearance from kidney and liver C) sum of clearance from non-renal clearances D) sum of renal and non-renal clearances
D
Which of the following are poorly perfused tissues? A) liver B) brain C) kidney D) adipose tissue
D
Which of the following is an advantage of sublingual administration? A) rapid absorption B) convenient C) avoid first pass effect D) all of the above
D
Drug A and drug B have VD values of 20 and 100L respectively. Both drugs have a Vp of 4L and a Vt of 10 L, and they are 60% bound to plasma protein. What is the fraction of tissue binding of the two drugs?
Drug A = 0.25 Drug B = 0.042
Factors associate with drug absorption that can result in incomplete absorption A) drug metabolism by gastrointestinal flora B) drug hydrophilicity C) drug instability in gastric acid D) presence of food in the GI tract E) all of the above
E
List two methods used by the pharmaceutical industry to measure the plasma protein binding of drugs
equilibrium dialysis and ultrafiltration
