Term
| Define pharmacokinetics and pharmacodynamics |
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Definition
-Pharmacokinetics= what the body does to a drug
-Pharmacodynamics= what the drug does to the body |
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Term
| What are the 4 pharmacokinetic properties that determine the speed of onset of drug action, the intensity of the drug's effect, and the duration of drug action? |
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Definition
-Absorption
-Distribution
-Metabolism
-Elimination |
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Term
| What is the bioavailability of a drug? |
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Definition
The fraction of administered drug that reaches the systemic circulation
Ex: if 100 mg of a drug are administered orally, and 70 mg of this drug are absorbed unchanged, the bioavailability is 0.7, or 70 percent |
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Term
| What is the equation for bioavailability? |
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Definition
| =(AUC oral/AUC injected)x100 |
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Term
| What is the first pass effect? |
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Definition
| the amount of drug that reaches general circulation can be much less than what is administered due to extensive metabolism by the liver (following absorption passage to hepatic portal vein) |
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Term
| What is a pro drug? Why would you use one? |
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Definition
a pharmacologically inactive compound that is converted into an active drug by metabolic transformation
-increase solubility
-prolong release
-biostability (keep the drug from being destroyed) |
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Term
| What is a zero order rate reaction? |
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Definition
| Loss of the drug is independent of the concentration of the reactants and constant with respect to time (Drug Elimination is independent of the concentration) |
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Term
| What is a first order rate reaction? |
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Definition
| Loss of the drug is directly proportional to the concentration remaining with respect to time. (Drug Elimination is dependent of the concentration) |
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Term
| What is the volume of distribution and what is the equation? |
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Definition
The volume of distribution (Vd) relates the amount of drug in the body to the concentration of drug (C) in the blood/plasma
Vd= Dose/ Cp0 |
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Term
| What is the maintenance dose? |
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Definition
| the dose administered every dosing interval to maintain the steady state condition |
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Term
| What is the loading dose? |
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Definition
| A single dose administered to reach the steady state condition instantly |
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Term
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Definition
| Proportionality constant describing the relationship between a substance’s rate of elimination(amount per unit time) at a time and its corresponding concentration(amount per unit volume) in an appropriate fluid at that time |
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Term
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Definition
| when, under a given dosage regimen, the mass (amount) of drug administered (for IV) or absorbed (for extravascular route), is equal to the mass (amount) of drug eliminated over a dosing interval |
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Term
| What is the elimination half life? |
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Definition
| Time (minutes, hours) at which the mass of the unchanged drug becomes half of the initial mass of drug as soon as the equilibrium is established after administering a dose |
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Term
| What is the therapeutic window? |
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Definition
| The range of drug doses that elicits a therapeutic response without unacceptable side effects |
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Term
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Definition
| The amount of drug needed to produce an effect(strength) |
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Term
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Definition
| The ability of a drug to produce the intended effect (effectiveness) |
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Term
| What is an adverse drug rxn? Example? |
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Definition
a response to a drug that is noxious and unintended and occurs at doses normally used for man for prophylaxis.
Ex: years of steroid therapy produces a "buffalo hump" |
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Term
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Definition
| An additional effect, desirable or undesirable, of a drug that is not the primary purpose of giving the drug |
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Term
| What are Cytochrome P450 tests useful when prescribing medications? |
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Definition
| there are 40 different enzymes and the presence or absence of these in patients can be used to determine the way specific drugs will interact with the patient |
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Term
| Define synergism in relation to drug interactions. |
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Definition
| The action of two drugs working together in which one helps the other simultaneously for an effect that neither could produce alone. Drugs that work together are said to be synergistic |
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Term
| Give an example of desirable synergism. |
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Definition
| Simvastatin (Zocor) lowers high cholesterol and gemifibrozil (lopid) lowers high triglycerides, so by giving small amounts of both together, high lipid levels can be treated more effectively |
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Term
| Give an example of undesirable synergism? |
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Definition
| sedatives and barbiturates given in combination can depress the CNS to dangerous levels |
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Term
| Define potentiation in relation to drug interactions. |
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Definition
| action of two drugs in which one prolongs or multiplies the effect of the other |
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Term
| Give an example of desirable potentiation. |
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Definition
| to build up a high level of some forms of penicillin in the blood, the drug probenecid (antigout drug) can be given simultaneously. Probenecid potentiates the effect of penicillin by slowing down the excretion rate of the antibiotic |
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Term
| Give an example of undesirable potentiation. |
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Definition
| toxic effect may result when cimetidine (Tagament-OTC) is given simultaneously with imipramine (Trofanil) antidepressant. Tagamet potentiates the level of antidepressant concentrations in the blood |
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Term
| What is antagonism in relation to drug interactions? |
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Definition
| Opposing action of two drugs in which one decreases or cancels out the effects of the other. |
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Term
| Give an example of desirable antagonism |
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Definition
| narcotic antagonist (naloxone-Narcan) saves lives from drug overdose by canceling out the effects of narcotics |
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Term
| Give an example of undesirable antagonism. |
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Definition
| Antacids taken with tetracycline may alter the pH and/or form chelates and prevent adsorption of tetracycline |
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Term
| What is a teratogenic effect? |
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Definition
| -maternal drug administration that causes the development of physical defects in a fetus (FDA pregnancy categories) |
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Term
| Define idiosyncratic in relation to response to a drug |
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Definition
| a unique, unusual, and unexpected response to a drug |
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Term
| Define paradoxical in relation to response to a drug |
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Definition
| opposite effect from that expected (e.g. a tranquilizer may cause a patient to become agitated and excited rather than tranquil) |
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Term
| Define tolerance in terms of response to a drug. |
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Definition
| decreased response to a drug that develops after repeated doses are given. To achieve the desired effect, the drug dosage must be increased or the drug replaced |
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Term
| Define dependence in terms of response to a drug |
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Definition
| acquired need for a drug that may produce psychological or physical symptoms of withdrawal when the drug is discontinued |
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Term
| What is psychological dependence? |
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Definition
| involves only a psychological craving; no physical symptoms of withdrawal other than anxiety |
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Term
| What is physical dependence? |
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Definition
| exists when cells actually have a need for the drug: symptoms of withdrawal include retching, nausea, pain, tremors, sweating |
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