PharmQ2 Flashcards
Affinity
the strength of binding between a drug and its receptor
(measure of affinity is called the dissociation constant (KD)
Efficacy
the degree to which a drug has an exact fit to the receptor or produces the desired effect
Agonist
a drug that binds to a cell receptor and causes an action
(has both affinity and efficacy)
Antagonist
(competive/noncompetitive)
a drug that inhibits or blocks the response of the receptor site
(has affinity but no efficacy)
Osmotic
pull water form tissues and cells due to a molecular size or chemical effect that attracts water
Chelator
Types of compounds used as drugs that physically combine with ions or other specific compounds to produce their effects
Bactericidal
Kills bacteria
Bacteriostatic
Inhibits reproduction
Minimum inhibitory concentration (MIC value)
the lowest concentration of drug at which growth of the bacterium is inhibited
Bacterial sensitivity
a sensitivity analysis is a test that determines the “sensitivity” of bacteria to an antibotic
Bioavailability
measure of the degree to which a drug is absorbed and reaches systemic circulation
Which route of administration produces the greatest bioavailablity
IV injection
skips the absorption phase => gets to tissues faster
Withdrawal time
the period of time after drug administration during which the animal cannot be sent to market for slaughter as food and the eggs or milk must be discarded
Which commonly used route of administration would skip the phase of absorption
IV injection
What primary organs are responsible for the phases of biotransformation
primary organ is the liver
other locations include the lungs, skin, intestinal tract, kidney, and nervous system
What primary organs are responsible for excretion
most drugs are excreted via the kidney into the urine
Other routes of elimination include the liver, lungs, salivary glands, milk, intestinal tract, hair, nails, and hooves
Which of the mechanisms of absorption require energy?
active transport and phagocytosis/pinocytosis
(no energy Diffusion = Facilitated diffusion, passive diffusion)
Protein binding
(drug distribution)
i. Some drugs will bind to proteins (albumin) in the blood and the large drug-protein complexes become trapped in the circulation.
ii. Animals with low protein levels will have less protein available for binding and more free drug available for the target tissues.
Volume of distribution
(drug distribution)
Drug concentration in the blood will lower if the drug has a large volume to distribute through.
ii. Diseases that produce extra body fluid (edema, ascites) will have less drug concentration in the blood and tissues due to a greater volume of distribution.
Storage sites
(drug distribution)
Drugs may become bound to other tissues such as milk, bone, and fat
Prodrug
Drugs that require biotransformation to become active
Google : a biologically inactive compound which can be metabolized in the body to produce a drug
What is the most common route of drug excretion?
Renal excretion
Factors affecting excretion
Renal perfusion, Clearance rate, Half life, Patient age, concurrent disease, percent of functioning nephrons, types of drugs/secondary drugs, tubulam,r reabsorption
Which species has a reduced ability to biotransform drugs due to deficiency of glucoronic acid needed for conjugation in phase 2 of biotransformation
felines
How does the pH of a drug vs an environment influence absorption
ionized - Positive or negative charge, tend to by hydrophilic, non-ionized - no charge and are neutral, tend to be lipophilic; drug molecules that move most effectivley across cell membranes are lipophilic/nonionized
Which tissues get a rapid rate of distribution?
Well perfused tissues (Active skeletal muscle, liver, brain and kidney
Which tissues get a slow rate of distribution?
Poorly perfused tissues (Inactive skeletal muscle and fat)
Adverse reactions of penecillins
Anorexia, vomiting and diarrhea; severe allergic reactions (esp when IV)
Why use semi synthetic penicillins over Pen G?
Pen G is inactivated by the stomach and semi-synthetics have a greater activity against gram negative bacteria
Which species should not be given penicillin. Why?
Species that should not be given penicillin due to GI superinfection: Guinea pigs, rabbits and hamsters
Why add procaine or benzathine molecules to Pen G?
Procaine and Benzathine molecules are added to IM suspensions to delay absorption and increase duration action
Know which groups of “cell wall” antibiotics are structurally and chemically similar due to containing the beta-lactam ring
Cephalosporins
How bacteria destroy cephalosporins
Bacteria synthesize beta-lactamase which breaks the beta-lactam ring causing the antibiotic to become inactive
Which cephalosporin can be potentiated by clauvonic acid
Amoxicillin can be potentiated to make clavamox or amoxiclav.
Antimicrobials in triple antibiotics
bacitracin, neomycin and polymyxin B
How sulfa drugs are classified
Classified by how well they are absorbed from the GI tract
Adverse effects of sulfa drugs
a. Crystal formation in the renal tubules
b. Hypersensitivity/severe allergic reactions
c. Skin reactions (pruritus, rashes, facial swelling)
d. Increased salivation in cats
e. KCS
f. Blood imbalances (leukopenia, thrombocytopenia, hemolytic anemia)
How sulfa drugs are potentiated
***?mechanism of how sulfa drugs are potentiated and 2 bacterial agents added for this purpose???
Contrast the forms of tetracycline
A. Hydrophilic forms: more likely to bind with calcium, magnesium, iron, etc.
B. Lipophilic forms: Human label only
Tetracycline adverse effects
a. Renal tubular necrosis at high doses
b. Slows development of teeth and causes yellow discoloration if used during pregnancy
c. Fever in cats
d. Nephrotoxic if outdated
e. Painful when given IM
f. May cause problems with cardiac contraction due to decreased calcium available
Tetracycline antimicrobial spectrum
Effective against gram + and gram - bacteria including mycoplasma and chlamydia
Aminoglycoside antibiotics
A. Tends to accumulate in the inner ear and kidneys, may cause adverse effects of ototoxicity and nephrotoxicity.
B. Contraindicated in animals with renal insufficiency
C. Not approved for use in food animals and should not be mixed with vials or syringes with other antibiotics
Fluouroquinoline group mechanism of action and contradictions
A. Rapid tissue penetration -> well absorbed into tissues with high availability
B. Crosses selective barrier
C. Contraindicated in young or rapidly growing animals.
Penicillin substitute and adverse rxns
Vancomycin; Ototoxicity, nephrotoxicity, and pain on IV injection
which antibiotic is very effective for treating anaerobic infections, dental disease and abscesses,
and in which species this antibiotic should not be used due to the potential for severe GI distress
Clindamycin
B. do not use in pocket pets or give orally to horses and ruminants
which antibiotic has been banned in the USA for use in food producing animals // the adverse effects associated with its use // Recall in which species this antibiotic may be more commonly used and the precautions that clients should take when using this drug.
Chloramphenicol; can cause fatal aplastic anemia in humans
***? commonly used and precautions??
