DDPharm1 Flashcards
Pharmacology
Study of the interactions of drugs with biological systems
Pharmacotherapy
Selection of the right drug in right dose to interact with right target to produce the desired therapeutic effects. These are the prevention/diagnosis/treatment or cure of a particular disease
Pharmacokinetics
What the body does to the drug. Relates to dose of drug and its absorption; distribution; metabolism and excretion. All of this leads to the plasma concentration (Cp) that results from the dose
Pharmacodynamics
AKA mechanism of action (what the druge does to the body). Relates to the Plasma concentration (Cp) of a drug and its receptor binding;signal transduction; physiological effects. All of this leads to the clinical effects (mechanism and magnitude of drug effect)
MEC
Minimum effective concentration. Can be determined for both the desired (therapeutic) response and any adverse responses
Onset of effect
Time to reach the MEC
Duration of effect
Time above the MEC
Therapeutic window (or therapeutic index)
Difference in plasma concentration [Cp] btwn the desired and adverse response MEC
Goal of pharmacotherapy
When multiple doses are administered it is to reach and maintain Cp at steady state with the therapeutic window to produce the desired response with a minimum of toxicity
Steady state
When rate of drug administration (Rate In) equals the rate of drug elimination (rate out)
Time to steady state
attained in 4-5 half lives when maintenance doses are administered at constant interval
Steady state concentrations
average Cp after steady state achieved
Fluctuations in Steady State Cp
related the number of half-lives in the dosing interval (time between doses)
Dosage regimen
Designed to ensure that the desired steady state drug level [Cpss(avg)] is maintained within the therapeutic window by balancing rate of drug elimination with the prescribed rate of drug administration. Key element in pharmacotherapeutics. Select drug/dose; route; frequency; duration
What is the selection of drug and dose based on?
Pharmacodynamics - Disease Targets - Drug Regulation
What is the selection of drug route of administration based on?
Pharmacokinetics. Leads to absorption and distribution of drug
What is the selection of dosage frequency based on?
Pharmacokinetics. Leads to metabolism and excretion
What is the selection of duration based on?
Disease Pathophysiology
Relationship of physiology; pathophysiology and pharmacology
Learn physiology to identify potention targets for drug action. Learn pathophysiology to learn how the target should be manipulated (enhanced or blocked) in a particular disease. Learn pharmacology to select appropriate drug to bring about desired manipulation
Bioavailability
How much of the dose of the drug reaches its target in the body (F)
Time to peak effect
How fast does the drug reach its target in the body (Tmax or Cmax)
Volume of distribution
What dose (mg) to obtain desired Cp (mg/L) (Vd)
Absorption
Passage of drug from the site of administration into the blood
Distribution
Movement of the drug from the bloodstream to tissues; where it accesses targets. Includes consideration of drug-protein binding; passage across BBB or placenta; selective accumulation affecting drug efficacy or toxicity.
Route of Administration
Site of application of the drug into or on the patient. Administered to obtain either systemic effects (absorbed into bloodstream and distribute to sites of action in the body) OR topical effects (mostly remain at site of application for local action)
Duration of action
How long will the drug stay at its target in the body. (Half-life)
Clearance
elimination of drug activity following drug administration by the combined processes of metabolism (liver) and excretion (kidneys). (CL)
Side effects
Drug target at non-target system. Seen at therapeutic doses. Dose-dependent and predictable
Extension effects
Drug target at target system. Seen at supra-therapeutic doses. Dose-dependent and predictable
Idiosyncratic reactions
Peculiar to an individual. Less predictable/less common. Immunologic or metabolic in origin
