Question | Answer |
Name the 3 phases of a drug taken by mouth? | Pharmaceutic(dissolution), Pharmacokinetic, Pharmacodynamic |
In what phase does the drug become a solution so that it can cross the biologic membrane? | The Pharmaceutic Phase |
What is a Parenterally given dosage? | This med dosage is one that is given and is administered by a route that bypasses the GI Tract (ex-IV, IM:Intramuscular, SubQ:subcutaneous) |
What are the 4 phases that make up the Pharmacokinetic phase? | Absorption, distribution, metabolism, excretion |
In order for a med in pill form to be absorbed what must it go through first? | pill goes through disintegration then dissolution (occurs in GI tract and happens in the Pharmaceutic phase) |
These are added to drugs to allow them to be a certain size, shape and to enhance drug dissolution so they can be readily absorbed.(ex: K, Na) | Excipients |
When smaller particles of drugs are dissolved in GI fluids before absorption what is it called? | Dissolution |
What is the time it takes for the drug to disintegrate and dissolve to become available for the body to absorb called? | Rate Limiting |
Drugs are absorbed more rapidly in a acidic or alkaline fluids? | absorbed in a Acidic fluid of 1 or 2 |
The young and old have more or less gastric acidity? | Less! so drugs are absorbed slower in the stomach! |
Which drugs resist disintegration in the gastric acid of the stomach? | Enteric-coated drugs(breakdown may not occur until they reach the alkaline environment of the small intestine) |
Which drugs should not be crushed because it would alter the place and time of absorption? | Enteric-coated drugs |
What is the process of drug movement to achieve drug action called? | Pharmacokinetic |
Name the 3 types of Absorption that move drug particles from the GI tract to the the body fluids? | Passive(diffusion from high to low con.), Active(Needs a carrier enzyme or Protein and ATP to move from low to high), Pinocytosis(drug engulfed and carried across membrane) |
Which drugs pass rapidly through the GI membrane? | Lipid soluble ones |
The GI tract is made mostly of what? | lipids and proteins |
What do water-soluble drugs need to pass through the cell membrane? | They need enzyme or protein carriers |
Large particles pass readily through the cell membrane when? | If they are non-ionized(no + or - charge) |
What can destroy some drugs like Penicillin G? | Gastric Acid |
How can drug lose be offset? | By giving larger Partial doses |
Which drugs do not pass through the GI tract or the Liver? | Parenteral drugs, eyedrops,eardrops, nasal sprays, respiratory inhalants, transdermal drugs, and sublingual drugs |
What drugs are absorbed through the skin and into the systemic system? | TDD Transdermal drugs |
Which drugs are absorbed under the tongue to avoid first-pass metabolism that occurs in the liver? | Sublingual drugs |
Which drugs are absorbed faster? | lipid soluble and nonionized ones |
what can affect drug absorption? | blood flow, pain , hunger, stress, fasting, food and Ph |
Drugs given Intramuscular-IM are absorbed faster because they have more blood vessels? | True Ex:Deltoids |
When drugs are taken orally they may not pass directly into the systemic system but may go where? | to the intestinal lumen to the liver via the Portal Vein |
In here drugs can be metabolized into a inactive form and be excreted in urine(this decreases the amount of active drugs available) | In the Liver |
What are drug Metabolites? | these are drugs that have been metabolized by the Liver and are equally or more active than the original drug. they cause a increased pharmacologic response. |
What is the first-pass effect? | This is when drugs pass to the liver first and most of the drug dose would be destroyed. |
What are some examples of first-pass metabolism drugs? | Coumadin(warfarin),Morphine, Lidocaine, some Nitroglycerins |
What is Bioavailability? | This is the% of administered drug dose that reached the systemic circulation. Its a subcategory of absorption. |
What is the % of bioavailability of oral drugs? | LESS THAN 100% |
What is the % of bioavailability of IV drugs? | 100% |
What is the % of bioavailability of first-pass hepatic metabolic oral drugs on entering the systemic circulation? | 20-40% |
A decrease in liver function or decrease in hepatic blood flow can do what to bioavailability of of a drug? | It can cause a increase in drug bioavailability if the drug is metabolized by the liver. |
How does drug toxicity occur with some oral drugs? | occurs if they are absorbed rapidly which will cause a increase in the drug concentration. |
Slow absorption of oral drugs causes what? | less drug available and causes a decrease in drug serum concentration. |
This is the process by which drugs become available to body fluids and body tissues | Distribution |
What can affect drug distribution? | blood flow, drugs affinity to the tissue, protein-binding effect. |
Volume of drug distribution Vd is dependent on what? | drug dose and concentration in body |
Drugs with a larger Vd stay in the body longer because of? | their loner half-life |
What protein do most drugs bind with? | Albumin |
highly bound protein drugs are what %? | >89%(11% is active) |
moderately-high bound protein drugs are what %(this part is inactive and cant cause a pharmacologic response)? | 61-89% |
moderately bound protein drugs are what %? | 30-60% |
What % are low protein-bound drugs? | <30% |
What are free drugs? | these are drugs that are not bound to proteins, they are active and can cause a pharmacologic affect. |
should 2 highly protein-bound drugs be given together? | No! because they would cause a increase in the amount of free drugs and thus possible toxicity would occur. |
When protein levels decrease what happens? | it decreases the # of protein-binding sites and can cause an increase in the amount of free drug in the plasma. |
How is drug dose prescribed? | it is done by the % in which the drug binds to protein |
What are Anticonvulsants? | these are drugs that prevent epileptic or convulsive seizures. they bind to Albumin |
which Antidysrhythmics bind to the protein component Globulin? | Lidocaine, Quinidine(prevent disturbances in rhythmic pattern of brain waves) |
Who has hypoalbuminemia because of low serum albumin levels, which results in fewer protein-binding sites? | The elderly because of malnutrition |
When there is a decrease in plasma proteins(albumin)what happens? | you get a decrease in protein-binding sites, which will permit more free drug in the circulation and may become life threatening. |
What is the primary site of drug metabolism? | The liver(also GI tract ) |
How do liver diseases like Hepatitis & Cirrhosis alter drug metabolism? | they inhibit the drug-metabolism enzymes in the liver,metabolism rate decreases and excess drug accumulation can occur and lead to toxicity. |
What is the time it takes for one half of the drug concentration to be eliminated called? | half-life(t1/2)--> affected by metabolism and elimination. |
Liver or Kidney dysfunction does what to the half-life of a drug? | It prolongs the half-life, and less drug is metabolized and eliminated. |
a short half-life of a drug is how long? | 8 hours |
A long half-life of a drug is how long? | 24 hours or longer. takes several days before drug is completely eliminated from body. EX: Digoxin |
Steady-state serum concentration is predictive of what? | Therapeutic drug effect |
The main route of drug elimination occurs where? | in the Kidneys(urine)-Filters unbound drugs, water-soluble drugs, and unchanged drugs |
The Urine pH(4.5-8) influences what? | drug excretion |
Acidic urine promotes excretion of what? | weak base drugs |
Alkaline urine promotes excretion of what? | weak acids drugs(aspirin) |
This is a metabolic byproduct of muscle that is excreted by the kidneys. | Creatinine |
What is CLcr or Creatinine clearance? | This is a test to determine Renal function. If renal function is decreased then drug dosage needs to be decreased. in the elderly the CLcr may be around 60 ml/min. |
What is the normal level for CLcr? | 85-135 ml/min. This value decreases with age. |
What is Pharmacodynamic Phase? | This is the study of drug concentration and its effects on the body. |
When you have a drug response what may occur? | You may get primary and secondary responses(these may be undesirable) |
Drug response is the relationship between what? | the minimal versus the maximal dose needed to produce the desired response. all drugs have different values at which they will be effective. |
When looking at pharmacodynamics what 3 things do we need to know about the drug? | We need to know the drugs onset of action(time to reach minimum effective concentration-MEC), peak action(drug reaches its highest blood or plasma concentration, duration of action(length time the drug has a pharmacologic effect) |
Where are drug binding sites primarily found? | proteins, glycoproteins, proteolipids, enzymes |
Name the 4 types of receptor families? | 1. kinase-linked 2. ligand-gated ion channels 3.G protein-coupled receptor 4. nuclear receptor |
Which receptor site has receptor in cell nucleus and has prolonged activation? | Nuclear receptors |
This is the site on the receptor in which drugs bind. | This is Ligand-binding domain |
Ligand-gated ion channels have drugs where? | These receptors have drugs that span the cell membrane that cause the channels to open and allow ion, usually K and Ca to flow in and out. |
This type of receptor is on the cell surface and the drug activates the enzyme inside the cell and a response is activated. | These are kinase-linked receptors |
What do G protein-coupled receptor systems have? | drug-->that activates---> receptor---> activates---> G protein----> activates----> effector |
What do Agonist do? | these are drugs that produce a response |
What do drug antagonists do? | these drugs block a response |
antagonists and agonists drugs lack what? | they lack specific and selective effects |
The receptors that are located in eyes,lungs,heart, bladder and blood vessels are called what? | Cholinergic receptors (and the drug affect all anatomic sites (ex- eyes, lungs etc.) of location, has 1 receptor site type) |
Drugs that affect various sites(but have the same type of receptor-cholinergic) are what? | Nonspecific drugs |
non-selective drugs affect what? | these drugs affect various receptors(ex-alpha-1 sites, Beta-1 sites, or Beta-2 sites) |
If a drug produces a response without acting on a receptor how does it do this? | it inhibits the production of hormones or the activity of enzyme activity. |
what are the 4 categories of drug action? | 1. stimulation or depression 2. replacement 3. inhibition or killing of organisms 4. irritation(laxatives irritate the lining of the colon to increase defecation and peristalsis) |
whats the half-life of a). penicillin and b). Digoxin(a antidysrhymthic) | 1=2hrs b=36 hrs. |
If a drug with a long half-life is given 2 or more times a day what will happen? | drug accumulation occurs and drug toxicity will occur. |
what is ED? | the Effective Dose in 50% of people /animals, in ratio form |
LD is what? | this is the lethal dose in 50% of people/animals. the closer it is to 1 the more lethal |
TI(therapeutic Index)= | LD/ED |
drugs with a high TI are? | in a wide margin of safety and have less chances of producing toxicity |
Peak drug levels indicate what? | the rate of absorption of the drug. |
Through drug levels indicate what? | the rate of elimination of the drug |
Tachyphylaxis refers to what? | this is a rapid decrease in response to a drug. |
Which drug classes can cause Tachyphlyaxis? | narcotics, barbiturates, laxatives, and psychotrophic agents |
What is Placebo effect? | This is a psychologic benifit from a compound that may not have the chemical structure of a drug effect. |