Question | Answer |
An____ is a compound that binds to a receptor and produces the biological response. | AGONIST |
Specialized target macromolecule that binds a drug and medicates its pharmacological action. | Drug receptor |
Enzymes, nucleic acids, or specialized membrane-bound proteins | Receptors |
More closely related to plasma concentration than dose-response curves. | Concentration-response curves |
Full agonist | The effect reaches 100% of the maximum possible. |
Partial agonist | Produces the biological response but cannot product 100% of the biological response even at very high doses. |
__________ is the maximal response a drug can produce. | Efficacy |
____________ is a measure of the dose that is required to produce a response. | Potency |
For example, drug A produces complete eradication of PVCs at a dose of 10 mg. Drug B produces complete eradication of PVCs at a dose of 20 mg. Both drugs have the same _______, but Drug A is _________ than Drug B. | Same efficacy (complete eradication of PVCs), A is more potent than B. It takes less of Drug A to produce the same effect. |
Drug C reduces PVCs by 60% and takes a dose of 50 mg to achieve the effect. Therefore, drug C has less _______ and less ______ in the reduction of PVCs compared to Drugs A and B. | efficacy and potency |
ED50 (effective dose) | Potency is often expressed as the dose of a drug required to achieve 50% of the desired therapeutic effect. |
___________ is a measure of drug safety. A drug with a higher ___________ is safer than one with a lower _____________. | Therapeutic index, therapeutic index, therapeutic index (7) |
____________ is the ultimate toxicity. | Death (7 |
The ___________ ___________ is the range of plasma concentrations of a drug that will elicit the desired response in a population of patients. | therapeutic window (7) |
____________ block or reverse the effect of agonists. They have no effect of their own. | Antagonists |
Binding of an ________ to a ________ does not produce a biological effect. | antagonist, receptor (7) |
The _________ can block the effect of an _________ or it can reverse the effect of an _________. | antagonist, agonist, agonist (7) |
An example of an antagonist is ___________, an _________ antagonist. | naloxone, opiod (7) |
No effect of its own. | Naloxone (7) |
Mechanism of action of B-blockers. | antagonist which blocks or reverses the effect of endogenously produced compounds, such as epinephrine or norepinephrine. (8) |
The __________ are competitive, they compete for the same site on the receptor as the agonist. If the _______ wins, a reponse is produced. If the ________ wins, no reponse is produced. | antagonists, agonist, antagonist (8) |
Increase the _________ of ______, increase odds that ________ will win the receptor spot and produce the effect. | concentration, agonist, agonist molecule (8) |
Reduces the maximal response that an agonist can produce. | Noncompetitive antagonist (8) |
________ _______ have opposite effects from those full agonists. They are not the same as antagonists, which block the effect of both agonists and inverse agonists. | Inverse agonists (9) |
______ increase the relative amount of time the channel is in open state compared to basal rate and _____ ____ decrease. | Agonists, inverse agonists (9) |
Leads to sedation. | GABAa receptor channel complex, agonists increase the amount of chloride that moves into neuron and will hyperpolarize it. (9) |
Leads to increase in excitability and can cause seizures. | An inverse agonist will decrease the amount of chloride that moves into the neuron, which will result in a depolarization compared to the resting state. (9) |
Inverse agonists bind to receptor and tip equilibrium toward the _________ state, agonists toward the ________ state | inactive, active (9) |
Bind to the receptor and have no effect on the basal state. | Antagonists (9) |
Liver is a metabolic machine, can inactivate drugs on their way to GI tract to body. This is called ____________ ____________ ________. | first-pass effect (11) |
Great chemical plant in the body. | Liver (11) |
Almost all require that the drug cross a _______ ________ to reach its site of action. | biological membrane (11) |
Drugs cross membranes by _______ _______ or _____ _______. | passive diffusion, active transport (11) |
Passive diffusion requires a _________ _______ across the membrane. Vast majority of drugs gain access to their site of action by this methods. | concentration gradient (11) |
_____________ _________ can penetrate the cell membrane through aqueous channels. | Water-soluble drugs (11) |
Just move through the membrane. | More commonly lipid-soluble drugs (11) |
A drug tends to pass through membranes if it is _________. | Uncharged (11) |
Uncharged drugs are more ______ ________ than charged drugs. Many drugs are _______ or ______. | lipid soluble, weak acids, weak bases (11) |
For a weak acid, when pH is less than pK, the _______ form (nonionized) ________. When pH greater than pK, the ______________ (ionized) form predominates. | protonated, predominates,unprotonated (12) |
Happy to give up a hydrogen ion and become charged. | Weak acids are hydrogen ion donors. (13) |
When you put HCL into water it immediately turns into ______ and _______. | H+ and CL-, use this example to remember weak acids donate a hydrogen ion and become charged. (12) |
If we _____________ the pH by adding more ____, we will move the equilibrium for the weak acid more to the left, which is the ________ (__________) form. | decrease, H+, nonionized, uncharged (12) |
If we __________ H+, making pH _______, we drive the equilibrium toward the _______. This increases the concentration of the _______ form of the ______ ______. | take away (or decrease), higher, right,ionized, weak acid (12) |
When the pH is _______ than the pK for the ______, the charged form of the acid predominates. | higher, acid (12) |
For a weak base, pH less than pK _________ _____ ______ ________. | ionized form (protonated) predominates (12) |
When pH is greater than pK, the _______ _____ form _______. | unprotonated (nonionized), predominates (2) |
Weak bases are ________ of weak acids. Weak base is a hydrogen ion acceptor. If a loose hydrogen ion seeks to join it, the base may accept it. If it accepts the hydrogen ion, then it becomes _______. | opposite, charged (12) |
In the stomach (pH 2.0) ____ ______ are uncharged and will be absorbed into the blood-stream, whereases _____ _______ are charged and will remain in the GI tract. | weak acids, weak bases (13) |
In the intestine (pH 8.0), which will be better absorbed, a weak acid (pK 6.8) or a weak base (pK 7.1)? | a weak base (13) |
If we alkalinize the urine to a pH of 7.8, will a lower or higher percentage of a weak acid (pK 7.1) be ionized, compared with when the urine pH was 7.2)? | Higher, because more weak acid will be ionized the more the pH exceeds the pK. (13) |
The amount of drug that is absorbed after administration by route X compared with the amount of drug that is absorbed after IV administration. X is any route of drug administration other than IV. | Bioavailability (13) |
Indicates rate which drug is cleared from the body. | Clearance (14) |
Clearance is defined as the volume of plasma from which all drug is removed in a given time. Thus, the units for clearance are given in _____ per ____ ____. | volume, unit time (14) |
Total body clearance | Sum of clearances from various organs involved in drug metabolism and elimination. (15) |
Is the mathematical description of the rate and extent of uptake, distribution, and elimination of drugs in the body. | Pharmacokinetics (16) |
Vd | Volume of distribution is a calculation of the apparent volume in which a drug is dissolved. (16) |
Vd = _____________ | Volume of distribution = Dose(mg)/plasma concentration (mg/ml) (16). |
Drug is lipid soluble and stored in _____. | fat (16) |
Most drugs disappear from plasma by processs that are concentration-dependent, which results in __________. | first-order kinetics. With first-order elimination, a constant percentage of the drug is lost per unit time. An elimination rate constant can be described. (17) |
ke | The elimination rate constant (units are 1/time) (17) |
Half-life | Period of time required for the concentration of a drug to decrease by one half. (17) |
t 1/2 = 0.693/ke | The half-life is constant and related to ke for drugs that have first-order kinetics. (18) |
Clearance of drug is _________ from the elimination rate. | different (18) |
Clearance | Volume of fluid cleared of a drug per unit time. (18) |
Rate of removal of drug in weight per unit time. | Elimination rate (19) |
Drugs with first-order kinetics, clearance and elimination rate are_______, | related (19) |
Zero-order kinetics | Drugs that saturate routes of elimination disappear from plasma in a non-concentration-dependent. (19) |
Involves specific enzymes which is one of the most important factors that contribute to a drug having zero-order kinetics. | Metabolism in the liver. (19) |
Many drugs show zero-order kinetics at ______, or _____ concentrations. | high, toxic (19) |
For drugs with zero-order kinetics, a constant amount of drug is lost per unit time. The _____ _______ is ____ constant for zero-order reactions, but depends on the ___________. | half-life, not, concentration (19) |
The ______ the concentration, the _______ the t 1/2. | higher, longer (19) |
Nonlinear or dose-dependent kinetics | Zero-order kinetics is also known as... (19) |
Refers to drugs that are first-order at lower doses and switch to zero-order at higher doses (often in the therapeutic range). | Dose-dependent, zero-order, and nonlinear (20) |
________ refers to the fact that drugs with zero-order kinetics do not show a linear relationship between drug dose and plasma concentration. | Nonlinear (20) |
When multiple dosing, or a continuous infusion, a drug will accumulate until the amount __________ per unit time is equal to the amount __________ per unit time. The plasma concentration at this point is called the ______ ____ ______ (Css). | administrated, eliminated, steady-state concentration (20) |
Elimination rate is proportional to the _____ ______ of the drug, so the concentration ______ so does the _________ rate. | plasma concentration, rises, elimination (20) |
Steady State | The infusion rate and the elimination rate are equal. (20) |
Css = ___________ | Css = Infusion rate (mg/min)/Clearance (ml/min) = mg/ml (20) |
Direct relationship between Css and the infusion rate (assuming clearance is constant). If we double the infusion rate, the Css _______. | doubles (21) |
Repeated dosing is associated with ______ and ________ plasma concentrations. | peak, trough (21) |
The time need to reach steady state depends ONLY on the _____ _____ of the drug. Ninety percent of steady state is reached in 3.3 half-lives. | half-life (21) |
3.3 half-lives equals _________. | 90% of percentage of steady state achieved (22). |
4 half-lives equals ________. | 94% of percentage of steady state achieved (22). |
5 half-lives equals ________. | 97% of percentage of steady state achieved (22). |
What is used if the half-life of a drug is long such as approx. 6 days for digitoxin to achieve a steady state (about 4 times the half-life)? This would take over 3 weeks. | Loading dose (22) |
Loading dose | Single dose of a drug used to raise the plasma concentration to a therapeutic level more quickly than would occur through repeated smaller doses. (22) |
Major site for drug metabolism. | Liver (24) |
Goal of metabolism is to produce ______ that are ______, or _______ and can be eliminated by the kidney. | metabolites, polar, charged (24) |
Frequently involve the P-450 system. | Phase I (24) |
Reactions are conjugations, mostly with glucuronide. | Phase II (24) |
Reactions convert lipophilic molecules into more polar molescules by introducing or unmasking a polar functional group such as -OH or -BG2. Most of these reactions utilize the microsomal P-450 enzymes. | Phase I (24) |
Plays a role in the metabolism of about 50% of the drugs. | CYP3A4 (24) |
Induces CYP3A4 which can increase metabolism of estrogen, thus reducing the effectiveness of birth control pills. | Rifampin (24) |
Conjugation reactions. | Phase II (24) |
Glomerular filtration, proximal tubular section, and distal tubular reabsorption. | Renal elimination involves 3 physiological processes. (25) |
Free drug flows out of body. Size of molecule is the only limiting factor. | Glomerular tubular secretion (25) |
Drugs are actively secreted into. | Proximal tubular section (25) |
Uncharged drugs, may diffuse out of the kidney and escape elimination. | Distal tubular reabsorption. |
Needs to be charged. | For a drug to be excreted so that it is trapped in the urine and can't cross the membrane to sneak back into the body. (25) |
When pH is _______ than pK, the unprotonated forms (A- and B) predominate. | higher (25) |
When pH is _______ than the pK, the protonated forms (HA and BH+) predominate. | less (25) |