Introduction Flashcards
Mechanism of action
Pharmacodynamics
Type of passive diffusion for large molecules
Aqueous diffusion
Type of passive diffusion that is the most important limiting factor for drug permeation
Lipid diffusion
Absorption, distribution, metabolism, excretion
Pharmacokinetics
Type of antagonist that binds reversibly
Competitive antagonist
Type of antagonist that binds at the active site or allosteric site
Noncompetitive antagonist
Type of antagonist that inactivates the agonist by modifying or sequestering it
Chemical antagonist (Protamine)
Type of antagonist that either blocks or activates a receptor
Physiologic antagonist (adrenergic antagonists)
Measure of the ability of the body to eliminate a drug
Clearance
Measure of apparent space in the body available to contain a drug
Volume of distribution (Vd)
Type of antagonist that binds to a receptor, competes with, and prevents binding of other molecules
Pharmacologic antagonist (Atropine)
Type of agonist that binds at the active site but only produces a partial response
Partial agonist (buprenorphine)
Type of transport that requires energy and a carrier; is saturable (low to high)
Active transport
Fractional extent to which a dose of a drug reaches its site of action
Bioavailability
Type of drug transport that does not require energy nor a carrier; is non-saturable (high to low)
Passive diffusion
A portion of the drug goes to the portal circulation and is metabolized in the liver resulting to a decreased drug effect before it reaches the systemic circulation
First-pass effect
Enumerate the CYP inhibitors (decrease in drug metabolism = increase in drug effect)
Sodium Valproate, Isoniazid, Cimetidine, Ketoconazole, Fluconazole, Alcohol (acute), Chloramphenicol, Erythromycin, Sulfonamides, Ciprofloxacin, Omeprazole, Metronidazole, Grapefruit juice, Amiodarone, Quinidine (SICKFACES.COM/GAQ)
Type of transport that does not require energy but requires a carrier; is saturable (high to low)
Facilitated diffusion
Principal organ in metabolism
Liver
Enumerate the CYP inducers (increase in drug metabolism = decrease in drug effect)
Barbiturates, St. John’s Wort, Carbamazepine, Rifampin, Alcohol (chronic), Phenytoin, Griseofulvin, Phenobarbital, Sulfonylureas (BullShit CRAP GPS)
Type of agonist that acts by abrogating the intrinsic activity of the free receptor
Inverse agonist
Rate and extent of disappearance of a drug from the site of administration and entry into systemic circulation
Drug absorption
Route of administration that has a 100% bioavailability
Intravascular
Route of administration that has a less than 100% bioavailability (has a lag phase)
Oral
The effect where a drug goes into portal circulation and gets metabolized in the liver leading to a decreased drug effect before it reaches systemic circulation
First-pass effect
A type of preparation that produces a slow, uniformed absorption of the drug for 8 hours or longer
Controlled-release preparations (extended-release, sustained-release, prolonged-action)
Route of administration that has a direct access to the systemic circulation via SVC (bypasses the liver, protecting it from first-pass effect)
Sublingual (Isosorbide dinitrate tablets for angina)
Route of administration that has a 50% bioavailability
Rectal (Diazepam suppositories for seizures in children)
Route of administration used for diagnostic agents
Intra-arterial
Route of administration to surpass the BBB and blood-CSF barrier
Intrathecal
Route of administration for non-irritating drugs (has a constant and slow rate of absorption to produce a prolonged effect)
Subcutaneous
Route of administration where fat composition is a factor in absorption (more fat = less blood vessels = delayed absorption)
Intramuscular
Route of administration where access to circulation is rapid
Inhalation (pulmonary absorption; lungs have a large surface area; salinase for nasal congestion, salbutamol metered-dose inhaler or nebulization for asthma)
When 2 (or more) drugs have the same active ingredients, have identical strength or concentration, and are given in the same route of administration
Pharmaceutical equivalents
Drugs converted into _ _ are more water-soluble and are more readily excreted
Inactive metabolites
Drugs converted into _ _ have the same effect but of longer duration
Active metabolites (Diazepam to Nordiazepam)
A compound that has no activity
Prodrug (Salicylic acid undergoes acetylation into AcetylSalicylic Acid or Aspirin)
Phase I of metabolism
Oxidation, reduction, hydrolysis -> addition of a functional group -> drug inactivation
Phase II of metabolism
Conjugation -> use of phase I by-product -> increased hydrophilicity -> elimination
Enzyme system for microsomal metabolism
Cytochrome P450 enzyme system (found in the liver, GIT, lungs, kidneys)
The time when half of the initial drug’s dose or concentration is reached or decreased
Half-life (t1/2)
The amount of drug present inside the body
Area Under the Curve (AUC)
Organ in drug excretion
Kidneys (also bile duct, lungs, skin)
A constant fraction of the drug is eliminated per unit time and t1/2 is constant (half of the drug is eliminated every x hours)
First-order elimination (most drugs follow this)
A constant amount of the drug is eliminated per unit time and t1/2 is variable (a specific amount of the drug is eliminated every x hours)
Zero-order elimination (ethanol in high blood levels, phenytoin in high doses, salicylates in toxic doses)
Refers to the volume of blood cleared of drug per unit time
Clearance (Cl) (constant in first-order)
The rate when the drug comes in which is equal to the rate the drug goes out (availability rate = elimination rate)
Steady state (usually 4-5 half-lives)
