Drug Biotransformation

Question 1

What is the best indicator of renal function in relation to drug dose determination?

Answer 1

• Decreased estimated GFR (eGFR)
• Increased Serum Creatinine

Indicators of the presence of impaired renal function

Question 2

What are the 2 different methods used to adjust drug dose regimes in patients with impaired renal function?

Answer 2

• Amount of drug administered is reduced, but the dosing interval is held constant.
  
  • Accounts for the bodies diminished ability to clear a drug
• Amount of drug administered is held constant, but the dosing interval is lengthened.
  
  • Useful in pts who require a specific dose, like antibiotics

Question 3

What INR value indicates that a dosage reduction of drugs metabolized by the liver should be considered?

Answer 3

INR > 1.7

attributable to hepatic failure

Question 4

What serum aminotransferase (ALT, AST) levels indicates that a dosage reduction of drugs metabolized by the liver should be considered?

Answer 4

> 4x normal

10 - 50 ~ normal

Question 5

What serum bilirubin level indicates that a dosage reduction of drugs metabolized by the liver should be considered?

Answer 5

> 2.0 mg/dL

Question 6

What serum albumin level indicates that a dosage reduction of drugs metabolized by the liver should be considered?

Answer 6

< 3.5 g/dL

Question 7

What platelet count indicates that a dosage reduction of drugs metabolized by the liver should be considered?

Answer 7

< 50,000 mm³

secondary to splenomegaly due to portal hypertension from cirrhosis or other liver disease

Question 8

What clinical signs indicate that a dosage reduction of drugs metabolized by the liver should be considered?

Answer 8

Acites or encephalopathy attributable to hepatic failure

Question 9

For an adult pt with a GFR > 50 mL/min, what is the interval at which amoxicillin (500 mg) should be administered?

Answer 9

Every 8 hours

(normal dose interval)

Question 10

For an adult pt with a GFR of 10 - 50 mL/min, what is the interval at which amoxicillin (500 mg) should be administered?

Answer 10

Every 8 - 12 hours

Question 11

For an adult pt with a GFR < 10 mL/min, what is the interval at which amoxicillin (500 mg) should be administered?

Answer 11

Every 24 hours

Question 12

For an adult pt with a GFR > 50 mL/min, what dose of codeine should be administered every 4 hours?

Answer 12

normal dose = 30 mg

Question 13

For an adult pt with a GFR of 10 - 50 mL/min, what dose of codeine should be administered every 4 hours?

Answer 13

Reduce dose 75% = 22.5 mg

Question 14

For an adult pt with a GFR < 10 mL/min, what dose of codeine should be administered every 4 hours?

Answer 14

Reduce dose by 50% = 15 mg