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31 Cards in this Set
- Front
- Back
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Define zero order kinetics
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Also referred to as saturation kinetics and is characterized by a constant amount of change per unit time
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Define rate of constant elimination
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For drugs that are eliminated by first-order kinetics, the rate constant is the fractional change per unit time (fraction/min, fraction/hour, etc) and is equal to:
ke = 0.693/t½ |
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How do you calculate clearance?
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Excretion rate/Concentration
[(mg/hr) / (mg/L) = L/hr] Dose/Area under the curve (AUC) [mg / (mg*hr/L) = L/hr] |
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Describe age related changes in creatinine clearance
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Based on cross-sectional studies, creatinine clearance decreases an average of about 8 ml/min/decade after age 30,
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Name major signaling mechanisms
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1.Intracellular response elements; transcription factors; DNA-coupled receptors
2.Transmembrane enzymes, including tyrosine protein kinases 3.Ligand gated ion channels (ionotropic) 4.G protein coupled receptors (metabotropic) |
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Describe the spare receptor concept
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A maximal effect can be produce by a drug when only a small proportion of receptor is occupied; the response is not linearly proportional.
Different drugs have varying capacities to initiate a response and consequently occupy different proportion of the receptors when producing equal responses. |
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Define drug efficacy
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the maximum effect of a drug is termed efficacy. This term does not refer to the therapeutic efficacy of the drug, but to the stimulus properties of the drug receptor complex
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Define drug potency
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- is a comparative measure that refers to the different doses of two drugs that are needed to produce the same effect.
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Interpretation of the dose response curve
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Partial agonists are less potent than the full agonist because the dose is smaller. It will have less efficacy. Efficacy is the height of the dose response curve. Right shift is less potent. Left shift is more potent. A full antagonist will have the same efficacy as a full agonist. True potency cannot be compared between the two.
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Interpretation of the therapeutic index curve
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will show at 50% who will die and at what point 50% will be therapeutic. This curve is more useful for showing adverse effects that aren’t always death. Therapeutic window is calculated between points of ED and LD 50s. Small bell curve is the population shown against the therapeutic effect. Also how you show narrow therapeutic windows such as lithium.
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Name 4 types of drug antagonism
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Competitive
Noncompetitive Physiologic (functional) Chemical (neutralization) |
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Describe competitive antagonism
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Most are competitive antagonists, those with the highest affinity wins unless you increase the number of agonists
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Describe noncompetitive antagonism
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Noncompetitive- changes structure of receptor so it cannot be recognized
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Describe physiologic antagonism
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Physiologic- type I allergic reaction. Epinephrine is the antagonist to histamine.
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Describe chemical antagonism
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Chemical- Protamine negates heparin by acid base neutralization. Not through a receptor mechanism
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Interpretation of dose response curve with an antagonist
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Dose response curve with use of a competitive antagonism- shifts to the right as more antagonist is added. Efficacy is unchanged as long as more agonist is added to the system to counteract the antagonist
Can’t tell difference between allosteric antagonism and others on graph? |
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Describe the two state model
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Here, antagonists are in eq. with agonists. Partial agonist will shift it both ways to inactive and active form; will generate some response but not anything close to pure agonism. Model explaining how three drugs are interacting on a receptors.
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Name changes in pharmacodynamics related to aging
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CNS more "sensitive"
Beta adrenoceptors "less sensitive" Orthostatic hypotension is more common Potassium, electrolyte imbalance is more common The incidence of occult blood loss with aspirin or NSAIDs is higher. |
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What is a biologic?
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A biologic is any virus, therapeutic serum, toxin, antitoxin, vaccine, blood, blood component or derivative, allergenic product, or analogous product applicable to the prevention or treatment or cure of a disease or condition of human beings.
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What is a Supplemental New Drug or Biologic Application
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When approval is sought for an additional indication for a drug already approved for another indication, a Supplemental NDA or BLA is filed by the manufacturer.
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What is the Abbreviated New Drug Application
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Application (ANDA). This FDA application encourages manufacturers to provide generic versions of pioneer (innovator) drugs which have lost patent status and have reverted to the common (public) domain. This usually results in increased competition and lower drug prices.
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What is the Biologics Price and Competition and Innovation Act of 2009
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established an abbreviated approval pathway for “biosimilars” for existing biologic products whose patent protection has expired. FDA Guidance has not been forthcoming on the criteria needed for approval of such products.
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What's an orphan drug?
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An orphan drug is one used for the diagnosis, treatment or prevention of a disease or condition affecting less than 200,000 people in the U.S.
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Name some provisions of the Clinical Use of Investigational Drugs Final Rule August 2009 (to see all, slide 29)
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Patients or patients to be treated must have a serious or immediately life-threatening disease or condition and potential benefit justifies the potential risks
The licensed physician under whose immediate direction an investigational drug is administered or dispensed for an expanded access use is considered an investigator. |
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Describe The Drug Price Competition and Patent Term Restoration Act of 1984 (Hatch-Waxman Act).
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Hatch-Waxman Act encouraged the development of new innovator drugs by extending patent rights and established procedures facilitating the approval of low-cost generic drugs.
First generic version of a brand-name innovator medication receives a 180-day period of market exclusivity. |
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What can vary in a generic equivalent?
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Inactive ingredients (excipients)
Tablet shape Color Taste Packaging |
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What cannot vary in a generic equivalent?
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Active ingredient
Formulation Route of administration Label and Dose Bioequivalency |
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Name bioavailability requirements of generics
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FDA requires that the 90% confidence intervals for the mean rate and extent of absorption of the generic product to be within (–20%/ +25%) of the mean bioavailability of the brand name product.
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What is off label prescribing?
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The prescription of a drug for an off-label indication is legal
At least 40% of all prescribing is for off-lable indications 75% to 80% off-label prescribing for infants and children; also high in cancer and psychiatry |
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What are prescriber responsibilities under the Controlled Substances Act?
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All physicians must register with that agency in order to prescribe the drugs under the control of the Act; Re-registration is mandatory every 3 yrs.
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How many refills are allowed under a schedule II drug?
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none
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