Term
| What metabolizes benzodiazepines? |
|
Definition
CYP3A4 & CYP2C19
Clorazepate decarboxylated in gastric juice |
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Term
| What metabolizes Buspirone? |
|
Definition
CYP3A4
Rifampin decreases plasma levels
Erythromycin, ketoconazole increases plasma levels |
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Term
| How is morphine metabolized? |
|
Definition
conjugation to active metabolites: morphine 6β glucoronide and morphine 3β glucoronide
Renal excretion, hepatic metabolism, short half-life of 3hrs |
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Term
| How are TCAs metabolized? |
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Definition
In the liver, excreted renally
Long 1/2 life, CYP450 screen is necessary
Caution in BPH, arrhythmia |
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Term
| What metabolizes Duloxetine? |
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Definition
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Term
| What are the pharmacokinetics of lithium? |
|
Definition
Mimics Na+
Excreted in the urine, 1/2 life avg is 20-24hrs
Renal absorption in the proximal tubules |
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Term
| How is lithium affected by diuretics? |
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Definition
Increased reabsorption by Na+-depleting diuretics
Na+ depletion (thiazides) promotes Li+ retention and toxicity
Increased excretion by volume-depleting diuretics |
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Term
| How do NSAIDS affect the resorption of Lithium? |
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Definition
| Facilitates proximal tubular reabsorption |
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Term
| How does carbamazepine metabolism affect dosage? |
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Definition
Powerful inducer of hepatic microsomal enzymes
Effects metabolism of other drugs & its own metabolism
After initial dose, 1/2-life of future doses is shortened
Significant dosage adjustments are necessary in first weeks of therapy |
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Term
| How is phenobarbital metabolized? |
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Definition
Inactivated by the microsomal enzyme system in the liver. 25% is excreted unchanged in urine (can be enhanced by increasing urine pH)
Powerful inducer of CYP enzymes |
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Term
| What reduces the absorption of Levodopa (L-DOPA)? |
|
Definition
Large neutral amino acids (LNAA)
Delayed gastric emptying |
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Term
| What metabolizes Levodopa in the periphery? |
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Definition
| Aromatic aminoacid decarboxylase (AAD) and to 3-o-methyldopa by the enzyme catechol-o- methyl transferase (COMT) |
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Term
| Ropinirole should be dose adjusted in what circumstances? |
|
Definition
| Metabolized by CYP1A2: adjust dose in presence of drugs that are metabolized by the same enzymes |
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Term
| Pramipexole should be dose adjusted in what circumstances? |
|
Definition
| Patients with renal insufficiency |
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Term
| What is the ranking of metabolism of inhaled anesthetics? |
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Definition
| Methoxyflurane > Halothane > Enflurane > Sevoflurane > Isoflurane > Desflurane > N20 |
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Term
| How are amino ester local anesthetics metabolized? |
|
Definition
| Rapidly inactivated in plasma and tissues by ubiquitous esterases |
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Term
| How are amino amide local anesthetics metabolized? |
|
Definition
| Mainly in the liver by cytochrome p450 enzymes and in general have longer plasma half-lives |
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Term
| What can help prolong the duration of amino amides? |
|
Definition
| Co-administration with epinephrine |
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Term
| How is succinylcholine metabolized? |
|
Definition
| Plasma cholinesterase (aka pseudocholinesterase, butyryl cholinesterase) but not by acetylcholinesterase |
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Term
| Describe the onset of succinylcholine |
|
Definition
| Rapid onset , short duration of action (minutes for a single dose) Duration may be prolonged in patient with genetic variants of pseudocholinesterase |
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Term
| Why is the duration of action of succinylcholine longer than acetylcholine? |
|
Definition
| Not subject to hydrolysis by acetylcholinesterase and therefore remains in the junction longer |
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Term
| Which isoqinolone based non-depolarizing blocker is the longest acting? |
|
Definition
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Term
| What is Hoffman's elimination? |
|
Definition
| Rapid spontaneous breakdown independent of renal or hepatic function |
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Term
| Which non-depolarizing blocker undergoes Hoffman's elimination? |
|
Definition
Atracurium and Cisatracurium
Broken down to form laudanosine and other products that readily cross the BBB
Can cause seizures with long-term use |
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