Pharm 1 Flashcards
Steps to bring a newly discovered drug into public use:
- Pre-clinical research2. IND/NDA–>PDUFA3. Phase 1 clin trials4. Phase 2 clin trials 5. NDA6. FDA review7. Drug hits the market8. Post market safety monitoring9. Phase 4 clinical trials
Investigational new drug application (IND)
1st contact w/ the FDA, makes it possible to test unapproved drugs in humans in accordance w/ strictly defined clinical protocols. To pass, must exhibit pharmacological activity that justifies commercial development cleared for phase 1 clin trials
PDUFA (Prescription Drug User Fee Act)
drug companies pay to support FDA resources, FDA agrees to process application in a timely manner
New Drug Application (NDA)
drug co files for this after completing phase 3 clin trials to initiate thorough review. A request to the FDA for marketing in the US. results = approved, approvable, or not approved.
Food, Drug, Cosmetic Act
-started in 1906-ensures correct labeling-ammended in 1938 to to require toxicity studies as well as NDA before promotion &distribution of new drugs- Ammended in 1962 to require proof of efficacy &documentation of safety.
Drug Schedules 1-5(used to classify by potential for addiction & abuse)
1: high potential for abuse. no accepted med use, lack of accepted safety as drug2:high potential for abuse. current accepted med use. abuse may lead to psycho or physical dependence3:less potential for abuse than 1&2. current accepted med use. mod or low potential for pays dependence, high potential for psycho dependence4. less potential for abuse than 3. current accepted med use. limited potential for dependence5. less potential for abuse than 4. current accepted med use. limited dependence possible
Controlled Drug Act
requires prescribers & dispensers to register w the DEA, pay a fee, receive a personal registration #, & keep records of all controlled drugs rx’d or dispensed.
Enteral routes of drug absorption
oral - swallowed, headed for GI sublingual - placed under tongue, dissolved/absorbed into blood stream through superior vena cava
Parenteral routes of drug absorption
IV - most common IM - aqueous soln’s absorbed quicklysubcutaneous
routs for drug absorption
- oral- sublingual- IV- IM- subcut.- inhaled- transdermal- intrathecal- rectal- epidural
delayed release preps of drugs
have a coating or ingredients that control how quickly the drug is released into the body. advantageous b/c you don’t have to take the drug as often. should not break or chew the tablet
depot preps
allow for a slow and sustained effect of the drug. drug is suspended in a non aqueous sol’n such as polyethylene glycol. usually given IM or subcut.
intrathecal pumps
administer med directly into CSF to avoid any delay. pain meds can be administered this way in order to reduce side effects of oral meds such as nausea
transdermal patches
slow & sustained release of drug. achieves a systemic effect. rate of absorption is highly variable depending on the location of the skin (ex: nicotine patches)
pH sustained preps
drugs that are intentionally altered to maintain a pH over a long period of time in order to alter the absorption (ex: long acting insulin injections)
patient controlled administration (PCA)
IV pump that allows pt to release med on their own as needed. usually used for pain mgmt in terminally ill pts
bioavailability
amount of drug administered that goes on to reach the systemic circulation.can be affected by the route the drug is administered as well as chem/physical properties of the drug.
loading dose
the administration of a drug in a single high dose to achieve desired plasma concentration rapidly, followed by maintenance dosing/infusion. often used when a delay in reaching steady state is unacceptable.
most drugs are absorbed more readily in their ______ state
unionized
most drugs are either a ____acid or a ____base
weak
an acid drug will be best absorbed in the
stomach
a basic drug will be best absorbed in the
small intestine
why should drugs which are absorbed in the stomach (acidic drugs) not be taken with food?
if the stomach becomes more basic, such as after eating a meal, an acidic drug will be less readily absorbed (due to increased ionization) than on an empty stomach, when it has a lower pH and a higher acid environment.
Plasma proteins
- Albumin (strongly binds acidic drugs)- Alpha 1 glycoprotein (binds lipophilic drugs)- Tracer proteins
what drugs permeate plasma membranes most readily?
small, nonionized, lipid soluble drugs
volume of distribution
the vol that would be required to contain the administered dose if that dose was evenly distributed at the concentration measured in the plasma. NOT a measurement of actual physiologic fluid in the body
the use of vol of distribution
to compare the drug distribution with the fluid compartments of the body as it would not be possible to test all areas of the body, so taking the measurable plasma concentration and extrapolating from there gives you a theoretical comparison.
fluid compartments of body
5% plasma20% interstitial40% intracellular
drug binding to plasma or tissue proteins results in ____ availability of free drug
lower
hypovolemia’s affect on the therapeutic effect of a drug
less overall body water vol means a greater drug concentration; increased therapeutic effects
Congestive heart failure : influence on therapeutic effect of a drug
decrease in blood flow; decreased clearance; decreased vol of distribution; no change in 1/2 life
morbid obesity: influence on therapeutic effect of drug
more lipid binding for lipophilic drugs –> less available free drug at any one time AND drug is staying in the body longer (diminished clearance rate)
hypoproteinemia: influence on therapeutic effect of a drug
less available plasma proteins –> less bound drug and more free drug –> increased therapeutic effect (must be careful so the do age does not enter toxic levels!)
characteristics of a drug w/ small vol of distribution
drug has largely stayed in the plasma and will readily be sent to the liver & kidneys for excretion. shorter 1/2 life in body.
characteristics of a drug w/ large vol of distribution
drug is eliminated when it is delivered to the liver or kidney. if drug is widely distributed, it has spread throughout all body water compartments, meaning less of it is in the blood and readily avail for delivery to the liver/kidneys. this results in the drug staying in the boy longer (increased 1/2 life, extended duration of action of the drug)
2 phases of liver metabolism
phase 1: drug polarity increased through redox reactions often by cytochrome P450 systemphase 2: conjugation reactions further increase polarity for highly lipophilic drugs. most common conduction is glucuronidation. most drugs are inactivated by conjugation.
enterohepatic cycle
drugs absorbed through the stomach are not able to take effect until they have passed through portal circulation and the liver. after first pass, the bioavailability can be measured and is a result of intestinal absorption, gastric metabolism, and hepatic metabolism
pro drug
an inactive drug that needs to be metabolically activated through norma pathways (a precursor to an active metabolite)
active drug
active form of drug after it has been processed by the body
inactive drug
unusable to body form of drug
toxic
a form of drug that has been converted to a poisonous form