Pharmacology Small Groups Flashcards
- How could a cell’s receptors become non-functional?
Receptor Internalization
Mutation in Gene
Increased Degradation (ubiquitination)
Phosphorylation
- Name this phenomenon. How does it change the sensitivity of the cellular response to the concentration of agonist?
Spare Receptor
- Draw 5 dose-response curves for this system, first with all the receptors being functional, as well as after 75%, 88%, 94%, and 98% of the receptors have been rendered non-functional.
What is the elimination rate constant, k, (in hr-1) for Drug Z in this patient?
2.77 hr-1
- What is the clearance, Cl, (in L/hr) of Drug Z in this patient?
42 L/hr
- What is the volume of distribution, Vd, (in L) of Drug Z in this patient? Is this high or low?
15.2 L
Not very high. Roughly 3 times the plasma volume
- Calculate the loading dose, DL, (in mg) of Drug Z that would be required in this patient to reach a target concentration of 14 mg/L? [Assume that the patient has not taken the drug previously.]
218.8 mg
Is half life related to Doubling Time?
No
What’s the importance of loading dose?
Reach steady state more quickly
How longn would a continous infusion take to bring the patient to a steady state of 14 mg/L?
4 times the half life
Case 4: A mother is breast-feeding her newborn, who is suffering from mild jaundice. The mother is being treated with a drug (Drug W) for a systemic infection. At steady state with a dosage regimen of 1000 mg every 6 hrs, an average concentration of drug of 185 mg/ml is found in the maternal plasma. Drug W is a weak base with a pKa of 4.4 and is inactivated by acetylation in the liver. The pH of plasma is 7.4 and that of breast milk is 6.4.
Drug W, if present in breast milk, could aggravate the child’s condition because Drug W displaces bilirubin from protein binding. Note that in general, if the ratio of the drug concentration in milk to its concentration in plasma is >0.05, a significant amount of drug will be present in the mother’s milk and reach the infant.
- Determine if a significant portion (>0.05) of drug W is likely to be present in the mother’s milk. [Assume that the distribution of Drug W is based solely on pH partitioning.]
Plasma = 1.001
Milk = 1.01
Case 4: A mother is breast-feeding her newborn, who is suffering from mild jaundice. The mother is being treated with a drug (Drug W) for a systemic infection. At steady state with a dosage regimen of 1000 mg every 6 hrs, an average concentration of drug of 185 mg/ml is found in the maternal plasma. Drug W is a weak base with a pKa of 4.4 and is inactivated by acetylation in the liver. The pH of plasma is 7.4 and that of breast milk is 6.4.
Drug W, if present in breast milk, could aggravate the child’s condition because Drug W displaces bilirubin from protein binding. Note that in general, if the ratio of the drug concentration in milk to its concentration in plasma is >0.05, a significant amount of drug will be present in the mother’s milk and reach the infant.
- What is the total Drug W concentration in the milk?
185 Micrograms/mL
Case 4: A mother is breast-feeding her newborn, who is suffering from mild jaundice. The mother is being treated with a drug (Drug W) for a systemic infection. At steady state with a dosage regimen of 1000 mg every 6 hrs, an average concentration of drug of 185 mg/ml is found in the maternal plasma. Drug W is a weak base with a pKa of 4.4 and is inactivated by acetylation in the liver. The pH of plasma is 7.4 and that of breast milk is 6.4.
Drug W, if present in breast milk, could aggravate the child’s condition because Drug W displaces bilirubin from protein binding. Note that in general, if the ratio of the drug concentration in milk to its concentration in plasma is >0.05, a significant amount of drug will be present in the mother’s milk and reach the infant.
- The child ingests @ 1000 ml milk/day. What is the amount of Drug W that the newborn will ingest/day?
185 Milligrams/Day
Case 4: A mother is breast-feeding her newborn, who is suffering from mild jaundice. The mother is being treated with a drug (Drug W) for a systemic infection. At steady state with a dosage regimen of 1000 mg every 6 hrs, an average concentration of drug of 185 mg/ml is found in the maternal plasma. Drug W is a weak base with a pKa of 4.4 and is inactivated by acetylation in the liver. The pH of plasma is 7.4 and that of breast milk is 6.4.
Drug W, if present in breast milk, could aggravate the child’s condition because Drug W displaces bilirubin from protein binding. Note that in general, if the ratio of the drug concentration in milk to its concentration in plasma is >0.05, a significant amount of drug will be present in the mother’s milk and reach the infant.
- Should the mother continue to breast-feed the baby? Assuming that the mother’s body wt. is 60 kg and that the baby’s body wt. is 3 kg, calculate the maternal dose and the baby’s “dose” in mg/kg/day. [Assume that the oral bioavailability of Drug W is 100%.]
Mother = 66.7 mg/day
Baby = 61.7 mg/day
Case 4: A mother is breast-feeding her newborn, who is suffering from mild jaundice. The mother is being treated with a drug (Drug W) for a systemic infection. At steady state with a dosage regimen of 1000 mg every 6 hrs, an average concentration of drug of 185 mg/ml is found in the maternal plasma. Drug W is a weak base with a pKa of 4.4 and is inactivated by acetylation in the liver. The pH of plasma is 7.4 and that of breast milk is 6.4.
Drug W, if present in breast milk, could aggravate the child’s condition because Drug W displaces bilirubin from protein binding. Note that in general, if the ratio of the drug concentration in milk to its concentration in plasma is >0.05, a significant amount of drug will be present in the mother’s milk and reach the infant.
If Drug W is a weak base with a pKa = 9.4, what would be the approximate ratio of Drug W’s concentration in plasma to its concentration in milk? [Assume that the distribution of Drug W is based solely on pH partitioning.]
Plasma = 100
Milk = 1000
Plasma to Milk 1:10
