pharmacokinetics Flashcards

1
Q

Pharmacokinetics

A

absorption, distribution, and metabolism, and excretion

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2
Q

Pharmacodynamic

A

drug concentration at site of action, therapeutic and AE- what the drug does to the human body

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3
Q

bioavailability
ranking

A

IV, SL, ODT, IR, ER

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4
Q

micronized

A

method used to increase the dissolution rate is to reduce particle diameter, which increase surface area

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5
Q

bioavailability
formula

A

10 0x (AUC-extravascular/AUC-intravenous) x
(Dose-intravenous/Dose- extravascular)

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6
Q

distribution

A

drug molecules moving from the systemic circulation to various tissue and organs.

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7
Q

factors that favor passage across membranes and greater drug distribution

A

and greater distribution:
- high lipophilicity
- low molecule weight
- unionized status
- low protein binding

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8
Q

if drug is high protein bound (>90%) and serum albumin is low (<3.5 g/dL)

A

higher percentage of drug will be in the unbound form (increased risk for ADR)

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9
Q

protein bound compounds

A

… many out their but common is phenytoin, calcium

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10
Q

calcium corrected formula

A

Ca(corrected)= Ca(reported-serum) + [(4.0 - albumin) x (0.8)]

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11
Q

phenytoin corrected

A

Phenytoin mcg/ml (corrected)=
(total phenytoin measured)/[(0.2 x albumin)+0.1)]

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12
Q

metabolism phase I

A

oxidation, reduction, and hydrolysis

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13
Q

metabolism phase II

A

conjugation

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14
Q

Cl

A

Cl =
elimination rate (mg/hr)/Concentration (mg/L)

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15
Q

dose adjustment for Michaelis-Menten kinetics

A

most drugs follow first-order kinetics
- at stead state, doubling the dose approximately doubles the serum concentration

some drugs (phenytoin, theophylline, and voriconazole) follow Michaelis-Menten (also called non-linear, saturable or mixed-order) kinetics
- doubling the dose of these meds can more than double the serum concentration
—-> using proportion to calculate a new dose is not appropriate
—-> dose adjustment must be made cautiously to avoid toxicity

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16
Q

Ke

A

Ke= Cl/Vd

17
Q

first-order t1/2

A

0.693/ke

18
Q

stead-state

A

at this point the intake of drug equals rate of drug elimination
approx 5 t1/2 to reach steady rate

so it means… so approx 5 t1/2 is needed to remove 95% of drug if no dose is given..