1st Exam Flashcards
What is enteral administration?
Into the GI tract-oral, rectal, NG tube, etc. Most drugs absorbed in small intestine.
What is sublingual admin?
Placed under the tongue. Absorbed in capillaries, bypasses liver and gastric secretions. Enhanced potency.
What is buccal admin?
Placed between cheek and gum. Absorbed in capillaries, bypasses liver and gastric secretions. Enhanced potency.
What is topical admin?
Placed directly onto the skin. Transdermal. Absorbed through skin into blood stream.
What is parenteral admin?
Injection. Most dangerous as meds act quickly. Dosage accuracy and aseptic technique required.
Types of parenteral admin?
Intradermal, subcutaneous, intermuscular, intravenous, intraarterial
What is inhalation admin?
Oxygen, inhalers, etc.
What does pharmacology mean?
Study of drugs in living systems
Difference in ‘medication’ vs ‘drug’?
Medication: substances prescribed for a treatment that produces therapeutic effects.
Drug: chemical substance that produces a biologic response in a living system
Intradermal?
Injected into dermis (just under skin), creates wheal (bump)
Subcutaneous?
Injected into subcutaneous layer at 45 degree angle
Intermuscular?
Injected into muscle at 90 degree angle
1938
Federal Food, Drug, and Cosmetic Act required accurate labels of ingredients and warning labels. FDA created.
1970
Controlled Substances Act set controls on abusive drugs. DEA established.
1990
Omnibus Budget Reconciliation Act (OBRA) mandated all OTC drugs be listed in patient’s charts. Pharmacists must provide drug review and patient counseling for new prescriptions.
What is drug classification?
Name
Mode of action
Whether prescription or OTC (how purchased)
Controlled substance classifications.
1-5, 1 most dangerous (Heroin, LSD). Labeled as CI, CII, etc.
Legal prescription must have included:
Patient info Drug name Dosage in proper units Dosage form Route of admin Date written Prescriber info/signature
What is biopharmaceutics?
Interrelatedness of chemical properties of a drug with its dosage form, route, and extent of systemic absorption.
The study of the chemical and physical properties of drugs and the biological effects they produce.
What is the term used for how a drug is compounded for delivery to a targeted area of the body?
Drug vehicle
Vehicle must be able to release drug at appropriate site
What is the term used for when a drug and vehicle are combined and used to deliver the drug? What are the 3 types?
Dosage form
Solid, liquid, gas
Examples of solid dosage forms
Tablet - active ingredient, fillers, dyes, disintegrator (turn drug into solution), outside coating, enteric—release into small intestine
Capsule - gelatin shell to mask taste, control release
Troches - lozenges
Examples of liquid dosage forms
Solutions - homogenous; drug dissolved in solvent
Emulsions - immiscible liquids
Suspensions - solid medication dispersed in liquid medium
Parenteral dosage form examples
Sub Q
IM
IV
Intradermal
Examples of gas dosage forms
Oxygen therapy
Anesthesia
Aerosol inhalers
Usually liquid medication in gas propellant- easily absorbed in lungs
What is disintegration?
Medication absorbed as liquid or gas
Solids must be liquefied before absorption
Ex: tablet into granules, into smaller particles, into solution, into absorption
What happens to the drug as it moves through the body?
Process of drug being absorbed, distributed, metabolized, eliminated
Effects of drugs
Cellular changes/drug actions
Physiologic changes/drug effects
-Systemic - reaches many areas of body
-Local - limited to administration area
Bioavailability
Proportion of administered drug that actually reaches systemic circulation (into blood stream)
Varies by: person, route, dose
Surface area available influences bioavailability
i.e. length of time for drug to reach destination
Influences of people processing drugs differently.
Age( elderly & very young) Nutritional status Ethnicity Existing physical condition (liver or kidney disease) Immune status Drug interactions Administration route State of mind Gender Genetics Weight Environmental factors Time of day
Influences of people processing drugs differently.
Age( elderly & very young) Nutritional status Ethnicity Existing physical condition (liver or kidney disease) Immune status Drug interactions Administration route (injection faster than tablet) State of mind Gender Genetics Weight Environmental factors Time of day
Systemic absorption locations
(Administration site to blood stream) Locations of absorption: GI tract Lungs Mucous membranes Eyes Skin Muscle Subcutaneous fat/tissues
Chemical properties of drug & vehicle must be compatible
Factors influencing absorption
Surface area - more surface area = better absorption (GI tract vs. pulmonary alveoli)
Blood flow- blood must get to absorption site (ruggae, alveoli highly vascular) (poor circulation can slow absorption)
Altered blood flow reduces absorption
Concentration- most drugs passive transport thru membranes (high concentration to low concentration) [some active transport (drug attaches to carrier protein, protein takes drug across membranes)]
Absorption factors (chemically)
Acid-base/pH Most drugs weak acid or weak alkaline Acid = stomach absorption Alkaline = small intestine absorption Neutral pH best for absorption Neutral charge = better absorption
Drugs easily pass through barriers similar of pH
What is lipophilicity and what does it do?
Ability of drug to dissolve in lipids
Allows for cross through lipid layers
Must still dissolve in water
Easily absorbed through stomach mucosa
Alcohol & drugs with alcohol are lipid soluble
Just water soluble drugs don’t pass through
Give by other routes-ex IV
What is lipophilicity and what does it do?
Ability of drug to dissolve in lipids (fats)
Allows for cross through lipid layers
Must still dissolve in water
Easily absorbed through stomach mucosa
Alcohol & drugs with alcohol are lipid soluble
Just water soluble drugs don’t pass through
Give by other routes-ex IV
Affects food in stomach has on absorption factors
Can slow drug absorption (why “take on empty stomach”)
Can buffer effects of stomach irritating drugs (why “take with food”)
What is the chelation effect?
Compatibility with other drugs
If two drugs combine and form precipitate, absorption is diminished which is Chelation effect
Ex: Tetracycline + milk/dairy/antacids (Ca++) = insoluble complex
(Doesn’t help you, they bind together)
What is passive transport?
Drug moves through cell membrane by diffusion High to low concentration Once equal, no more diffusion Lipid solubility most important factor (Passive occurs most often)
What is active transport?
Requires energy from cell and carrier molecule
Enzyme or protein combines with drug molecule on membrane surface; carries it through, then dissociates
Pinocytosis: cell engulfs drug particle in membrane , pulls into cell, and releases it
At what location in circulatory system will the drug get to its target?
At capillaries and across membranes
Drug passes through stomach mucosa/cell membranes via _____ or ______ transport.
Active, passive
Drug travels to the action site through ___
The bloodstream
Once the drug arrives at the action site, it gets into the target tissues by passing _____
Through cell membranes
What is selective distribution?
Specific properties of drug affect movement (same properties, different distribution rate)
Some drugs have affinity for certain organs/cells (human chorionic gonadotropin targets ovaries-where absorbed)
Lipophilicity affects movement to target tissue
Blood-brain barrier
Placental barrier
Factors affecting distribution
Cardiac output (amount of blood pumped per minute) Regional blood flow (blood supply to specific organ or tissue) Drug reservoirs (specific sites that hold drugs. Ex: plasma, fat tissue, bone)
Plasma proteins - drug binding to this inactivates the drug (free drugs, once used cause bound drugs to become free)
Distribution barriers
Blood-brain - drugs meant to cross must be lipid soluble, minimally binding to plasma
Placenta - not selective, lots of drugs can pass, first trimester most important
Metabolism of drugs
Chemical changes to drugs (change drug from fat soluble to water soluble-metabolite excreted)
Liver primary organ (also: kidneys, lungs, intestinal mucosa, plasma)
Types of chemical changes:
-Oxidation, hydrolysis, reduction (gain an e-)
-Conjugation (transform from lipid soluble to water soluble. Excrete thru biliary tract and/or kidneys)
Abnormal drug metabolism
Prolonged by: liver disease, cardiovascular disease, renal problems (won’t excrete properly), immature metabolizing enzyme systems (children), degenerating enzyme function (not able to process drugs).
Delay in excretion can mean overdose
First pass phenomenon: oral drug goes through liver first before general circulation. Drug can deteriorate before reaching general circulation if liver disease is present-less effective
First Pass Effect
PO drug: mouth—stomach—small intestine—mesenteric vascular system—portal vein—liver—systemic circulation.
Some of drug metabolized through this process, loses effectiveness- partial metabolism
May require higher dose of an oral drug
Methods that avoid first pass effect
Sublingual
Vaginal
Parenteral (water soluble)
Rectal
(Think water and oil-don’t want oil (lipids/fats) in your blood stream-could cause embolism)
Enterohepatic Recycling
Certain drugs once absorbed, move from bloodstream to liver, then through biliary tract.
Excreted in bile OR return to small intestine and back into bloodstream
Result: drug stays in body for a long time (risk of toxicity)
Half-life
Time it takes for presence of drug in the body to decrease by 50%
Influences frequency of administration in order to keep plasma levels even