Module 4 & 5: Prescription Writing, Pharmacodynamics, & Pharmacokinetics

Prescription

an order to the pharmacist written by a licensed vet, physician, dentist to prepare & dispense the prescribed medicine to the client/patient

Inscription

list of the name/s & amount/s of drugs in

the prescription

Subscription

obsolete (not used anymore); gives the

instruction to the pharmacist on how to prepare

medicine

Signa

consist of instruction for administration

of medicine

Erroneous prescription

Type of prescription:
→ Brand name precedes generic name

→ Generic name the one in parenthesis

→ Brand name is not in parenthesis

Violative prescription

Type of prescription:
→ Generic name is not written

→ Generic name is not legible & brand name is legible

→ When brand name is indicated & instruction such as “no substitution” is added

Impossible prescription

Type of prescription:
→ When only the generic name is written but not legible

→ When generic name doesn’t correspond to the brand name

→ When both generic & brand name are not legible

→ When there is no such product corresponding to the dosage form and/or drug concentration

→ When drug product is not registered

Drug receptor interaction

drug must bind to a receptor to produce an action

Drug

any chemical substance that affects living processes

Receptor

normal component of tissue where drug

can bind

Biophase

once drug binds to receptor, this must be met; to establish & maintain for a certain time

Graded dose response relationship

as the dose of a drug is increased, the magnitude/intensity of the response/effect also increased

Quantal dose response relationship

as the dose of the drug is increased, the number/proportion of animal exhibiting a response is also increased; an all or nothing response

ED50

the median effective dose; dose that will produce desired response in 50% of the animal population

LD50

median lethal dose; dose that will produce death in 50% of animal population; dose needed to kill 50% of animal population

Agonist

drug that possesses affinity for a particular kind of receptor & the ability to cause a change in this receptor that give rise to an observable effect

Antagonist

any drug that counteracts the effect of an agonist; produce a different effect from the agonist

Pharmacologic antagonist

antagonism that interact w/the receptor or any component of the receptor or any component of the effector mechanism to inhibit the action of agonist

Non-competitive antagonist

prevents the agonist from producing its effect at a given receptor site, it also inhibit any component of the stimulus (allosteric site)

Chemical antagonist

type of antagonism where a drug counters the effect of another by simple chemical reaction/neutralization (not binding to the receptor)

Affinity

tendency of a drug to combine with a particular kind of receptor

Efficacy

characterized by the maximal effect the drug can produce; drug are usually described by their most prominent effect

Specificity

when all the effects produced by a drug are due to a single mechanics of action

Potency

dose that must be administered to produce a particular effect of given intensity

Safety

measured by ratio & proportion; therapeutic index & certain safety factor