Therapeutic Drug Markers Flashcards
The mechanism of action is defined as the biochemical or physical process that occurs at the ___ to produce the pharmacological effect.
site of action.
For drug administration, the parenteral route is defined as…
Outside the intestine (i.e., IV, IM, SQ, etc.).
Drug action is ___ mediated at the cellular membrane.
receptor.
For drug administration, GI absorption can include…
Rectal/suppository.
The rate of absorbance is classified by which two biochemical methods?
Passive diffusion and dietary transport mechanism.
Which GI changes can affect drug absorption?
GI motility, pH, inflammation, food, and other drugs.
Define first pass metabolism.
a drug gets metabolized at a specific location in the body that results in a reduced concentration of the active drug upon reaching its site of action or the systemic circulation.
Which drug type correlates with therapeutic and toxic physiological effects? (Bound or Free)
Free drug.
Which two factors effect the amount of free drug available?
(1) Serum protein level; (2) Competitive binding for the receptor on the transport protein.
What is the major site of metabolic clearance and biotransformation?
Liver.
Unmetabolized drugs are termed the ___ compound; metabolized products are termed ___.
parent; metabolites.
Define xenobiotic.
Exogenous substances (drugs) that are capable of entering the metabolic pathway.
Describe Phase I enzyme reactions.
Chemical structure modification produces reactive intermediates.
What is the enzyme responsible for Phase I Enzyme reactions?
Cytochrome P450.
Describe Phase II Enzyme reactions.
The drug becomes water soluble because of the conjugation of the functional group.
How does the depletion of conjugate groups effect Phase I & II enzyme reactions?
Can create a backup of Phase I reactive intermediates which may become toxic.
How are free form drugs and metabolites eliminated by renal clearance?
Glomerular filtration - renal secretion through the tubules.
The rate of drug clearance correlates with ___ clearance.
creatinine.
How will a decreased GFR effect serum half life and concentration?
It will cause it to increase.
An IV bolus of a drug is what type of elimination?
First-order.
Define half life.
Time required for the concentration to be decreased by one half.
Define the drug distribution rate.
How long it takes the drug to distribute throughout the body.
Define minimum effective concentration (MEC).
Lowest concentration of the drug in the blood that will produce the desired result.
Define minimum toxic concentration (MTC).
The lowest concentration of the drug in the body that will produce an adverse response.
Define the therapeutic index.
The ratio of MTC/MEC; varies from drug to drug and patient to patient.
Define the therapeutic window.
Range between MEC and MTC.
Define trough.
Lowest concentration of drug measured in the blood.
Define peak.
Highest concentration of the drug measured in the blood.
The following graph is indicative of what type of elimination?
First-order
What is the most important factor of TDM sample collection?
Timing; trough or peak.
What samples are collected for TDM testing?
Serum or heparin plasma.
Why should gel tubes be avoided for TDMs?
They absorb drugs and cause a false decrease.
Why is EDTA avoided for TDM testing?
There is a change in distribution of drugs between cells and plasma.
Calcium binding anticoagulants can cause changes in ___ between cells and plasma.
distribution.
What is the most common testing method used for TDM?
Immunoassay.
What complex lab methods are used for TDM testing?
Gas liquid chromatography (GLC); High Performance Liquid Chromatography (HPLC).
Digoxin is used to treat…
Hear failure & arrhythmias.
Therapeutic range of Digoxin.
0.8 - 2.0 ng/mL.
Mechanism of action for Digoxin.
Increases cardiac contractility;
Inhibits Na, K, ATPase membrane pump decreasing intracellular K;
Increases intracellular calcium;
Increases cardiac contractility.
3-Procainamide is used to treat…
Inappropriate ventricular contractions; tachycardia.
Therapeutic range of 3-Procainamide.
4 - 12 ug/mL.
Mechanism of action for 3-Procainamide.
Reduces cardiac excitability;
Increases the threshold membrane potential by blocking K outflow.
3-Procainamide testing tests what two metabolites?
Procainamide and NAPA.
4-Quinidine is used to treat…
Many types of arrhythmias after myocardial infarction.
Therapeutic range of 4-Quinidine.
2 - 5 ug/mL.
Mechanism of action of 4-Quinidine.
Reduces cardiac excitability;
Increases the threshold membrane potential by blocking K outflow.
Aminoglycosides (antibiotics) are used to treat…
Aerobic gram negative bacterial infections.
What is the mechanism of action for aminoglycosides?
Inhibits bacterial protein synthesis by binding the 30S ribosomal subunit.
What is the therapeutic range for Gentamicin?
Peak: 5 - 8 ug/mL.
Trough: 1 - 12 ug/mL.
What collection type should be used for Gentamicin?
Serum only.
Vancomycin is used to treat…
Gram positive and some gram negative Methicillin resistant Staphyloccoci Endocarditis.
What is the peak and trough therapeutic range of Vancomycin…
Peak: 20 - 40 ug/mL.
Trough: 5 - 10 ug/mL.
What is the mechanism of action for Vancomycin?
Bactericidal, inhibits cell wall synthesis.
Chloramphenicol is used to treat…
Broad spectrum antibiotic for resistant bacteria.
Concentrates in the cerebrospinal fluid.
Therapeutic range for Chloramphenicol.
6 - 12 ug/mL.
Mechanism of action for Chloramphenicol.
Inhibits bacterial protein synthesis by binding the 50S ribosomal subunit.
1-Phenytoin is used to treat…
Corrects for grand mall seizures.
Therapeutic range for 1-Phenytoin.
10 - 20 ug/mL.
Mechanism of action for 1-Phenytoin.
Reduces synaptic transmission by modulating sodium channels.
2-Phenobarbital and Primidone is used to treat…
Corrects for all types of seizures except absence (petit mal).
Therapeutic range of 2-Phenobarbital and Primidone.
Phenobarb: 15 - 40 ug/mL.
Primidone: 5 - 12 ug/mL.
What is the mechanism of action of 2-Phenobarbital and Primidone?
Reduces synaptic transmission, potentiates inhibition through the GABA receptor, increasing chloride flow.
Carbamazepine is used to treat…
Seizures and trigeminal neuralgia (facial pain).
What is the therapeutic range of Carbamazepine?
4 - 12 ug/mL.
What is the mechanism of action for Carbamazepine?
Reduces synaptic transmission by modulating sodium channels; antidiuretic effect.
Valproic acid is used to treat…
Petit mal, absence seizures. Used in combination with other antiepileptics.
What is the mechanism of action for Valproic acid?
Reduces synaptic transmission; GABA transaminase inhibitor, increases GABA inhibition.
Lithium is used to treat…
Bipolar disorder, manic phase.
What is the therapeutic range of Lithium?
0.8 - 1.2 mmol/L.
What is the mechanism of action of Lithium?
Enhances reuptake of catecholamines; sedating effects on the CNS.
Tricyclic Antidepressants are used to treat…
Depression, insomnia.
What is the therapeutic range of tricyclic antidepressants?
50 - 150 ng/mL.
What is the mechanism of action for tricyclic antidepressants?
Inhibition of reuptake of catecholamines in the CNS; positive effect on mood.
Theophylline is used to treat…
Asthma and COPD.
What is the therapeutic range of theophylline?
8 - 20 ug/mL.
What is the mechanism of action of Theophylline?
Relaxes bronchial smooth muscle; antagonist of adenosine receptors in smooth muscle.
Caffeine is a minor metabolite of ___.
Theophylline.
Caffeine is used to treat…
Neonate apnea.
What is the therapeutic range of caffeine?
8 - 14 ug/mL.
What is the mechanism of action for caffeine?
Relaxes bronchial smooth muscle; antagonist of adenosine receptors in smooth muscle.
