Exam 1- Intro to Pharm, Pharmacokinetics, Pharmacodynamics, Drug Development, Steroids&Biologics, Rx Writing, Antineoplastics, Pain Meds, Opioid Agonists, Pain Management Flashcards
pharmacology
biomedical science/study of the interaction of chemical substances or drugs with living cells, tissues, and organisms
drug
natural product, chemical substance, or pharmaceutical preparation intended for administration to a human or animal to diagnose or treat a disease
pharmacotherapeutics
medical science concerned with the use of drugs in the treatment of disease
toxicology
the study of poisons and organ toxicity; the harmful effects of drug and other chemicals on living systems
pharmacokinetics
what the body does to the drug
processes that determine the concentration of drugs in body fluid and tissues (drug plasma concentration) over time (drug absorption, distribution, biotransformation=metabolism, excretion)
pharmacodynamics
what the drug does to the body
study of the actions of drugs on target organs
What concepts are involved with pharmacokinetics?
Dose of drug -> Drug concentration in target organ over time
Absorption, Distribution, Biotransformation (Metabolism), and Excretion are involved
What concepts are involved with pharmacodynamics?
Drug concentration in target organ over time -> Mechanism and magnitude of drug effect
Receptor binding, Signal transduction, and Physiological effect are involved
What are 3 main drug sources?
Natural products- plants, microbes, animal tissues, minerals (i.e. lithium)
Chemical substance- synthetic, semisynthetic (i.e. oxycodone)
Pharmaceutical preparation
What are some drug preparations?
Crude, Pure, Tablets, Capsule, Solutions, Suspensions, Skin patches, Aerosols, Ointments, Creams, Lotions, Suppositories
Crude Drug preparation
Obtained from natural sources (such as opium from the dried juice of the poppy seed capsule).
What are advantages/disadvantages of crude drug preparation?
A crude drug preparation retains most or all of the active and inactive compounds contained in the natural source from which it was derived. However, it is difficult to identify and quantify the effects of the prep because of multiple ingredients and the amount varies from batch to batch
Pure Drug preparation
Isolation of pure drug compounds from the natural sources
i.e. morphine, insulin
Tablet preparation
In the manufacture of tablets, a machine with a punch and die mechanism compresses a mixture of powdered drug and inert ingredients into a hard pill
What are inert ingredients in tablets and what is their purpose?
Fillers- provide bulk
Lubricants- prevent sticking to the punch and die during manufacturing
Adhesives- maintain tablet stability
Disintegrants- facilitate solubilization of tablet when it reaches gastrointestinal fluid
Pharmaceutical preparation
Pharmaceutical preparations or dosage forms are drug products suitable for administration of a specific dose of a drug to a patient by a particular route of administration.
enteric coatings
A polymer coating around a tablet that will not dissolve in gastric acid but will break down in the more basic pH levels of the intestines
What is the importance of enteric coatings?
To protect drugs that would otherwise be destroyed by gastric acid and to slow the release and absorption of a drug when a large dose is given at one time
What are sustained-release or extended-release products?
These products release the drug from the preparation over many hours
What are some methods used to extend the release of a drug?
Controlled diffusion- release of the drug from the pharmaceutical product is regulated by a rate-controlling membrane
Controlled dissolution is done by inert polymers that gradually break down in body fluids. These polymers may be part of the tablet matrix, or they may be used as coatings over small pellets of drug enclosed in a capsule
Osmotic pressure- these products contain an osmotic agent that attracts gastrointestinal fluid at a constant rate. The attracted fluid then forces the drug out of the tablet through a small laser-drilled hole
Capsule preparation
Hard gelatin shell- enclose powders
Soft gelatin shell- enclose liquid or solution
What is the most common preparation for oral route of administration? Why?
Tablets and capsules are the most common preparations for oral administration because they are suitable for mass production, are stable and convenient to use, and can be formulated to release the drug immediately after ingestion or to release it over a period of hours.
What is the most common liquid drug preparation?
Solutions and suspensions
Why are solutions and suspensions convenient?
Why are they less convenient than solid dosage forms?
Convenient because they provide a method of administering drugs to individuals unable to easily or safely swallow tablets or capsules
Less convenient than solid dosage forms because the liquid must be measured each time
What are the oral administration preparations of solutions/suspensions?
syrups- sweetened aqueous solutions
elixirs- sweetened aqueous-alcoholic solutions
How are parenteral preparations of solutions/suspension administered?
Sterile solutions/suspensions are administered directly into system via needle and syringe/infusion pump
Skin Patches
Transdermal skin patches are drug preparations in which the drug is slowly released from the patch for absorption through the skin into the circulation
How do skin patches regulate diffusion of drug?
Most skin patches use a rate-controlling membrane to regulate the diffusion of the drug from the patch
Such devices are most suitable for potent drugs, which are therefore effective at relatively low doses, that have sufficient lipid solubility to enable skin penetration.
Aerosols
Drug preparation administered via inhalation through the nose or mouth.
Usually local effect, but can also be absorbed through mucosa to exert systemic effects
Ointments & Creams
Drug preparation administered via topical application. The active drug is incorporated into a vehicle which enables the drug to adhere to tissue for a sufficient length of time to exert effect
Lotions
Drug preparation administered via topical application. Liquid preparations often formulated as oil-in-water emulsions and are used to treat dermatologic conditions
Suppositories
Drug preparation used for rectal, vaginal, or urethral administration. The active drug is incorporated into a solid base that melts or dissolves at body temperature. Can produce local or systemic effects
What are some common routes of drug administration?
Enteral, Parenteral, Transdermal, Inhalation, Topical
What are examples of enteral administration?
Oral- has the biggest barrier to absorption
Sublingual- drug product is placed under the tongue (quick absorption because of vasculature)
Buccal- drug is placed between cheek and gum
Rectal
What are examples of parenteral administration?
Intravenous (IV)- drug is delivered directly into systemic circulation
Intramuscular (IM)
Subcutaneous (Subcut)
Intrathecal- injection of a drug through the thecal covering of the spinal cord and into the subarachnoid space
Epidural- injection of drug into space above the dural membranes of the spinal cord
What are the advantages and disadvantages of oral route?
Advantages- convenient, relatively safe, and economical (easily mass produced)
Disadvantages- cannot be used for drugs that are inactivated by gastric acid, for drugs with large first-pass effect, or for drugs that irritate the gut
What are advantages/disadvantages of IM route?
Advantages- suitable for suspensions and oily vehicles, absorption is rapid from solutions and is slow and sustained from suspensions
Disadvantages- may be painful, can cause bleeding if patient is receiving an anticoagulant
What are advantages/disadvantages of Subcut route?
Advantages- suitable for suspensions and pellets, absorption is similar to that in IM route but is usually slower
Disadvantages- cannot be used for drugs that irritate cutaneous tissues or for drugs that must be given in large volumes
What are advantages/disadvantages of IV route?
Advantages- bypasses absorption to give immediate effect, allows for rapid titration of drug, achieves 100% bioavailability
Disadvantages- poses more risks for toxicity and tends to be more expensive than other routes
What are examples of transdermal, inhalational, and topical routes of administration?
Transdermal- skin patches
Inhalational- aerosols
Topical- lotions, creams, ointments
What is the chemical name of a drug?
Specifies the chemical structure of the drug and uses standard chemical nomenclature
What is the proprietary/trade/brand name of a drug?
The registered trademark belonging to a particular drug manufacturer and used to designate a drug product marketed by that manufacturer
What is the non-proprietary/generic name of a drug?
The type of drug name most suitable for use by health care professionals.
In the United States the preferred nonproprietary names are the United States Adopted Name (USAN) designations. These designations, which are often derived from the chemical names of drugs, provide some indication of the class to which a particular drug belongs
What are the pharmacokinetic processes?
Absorption, distribution, and biotransformation
What is drug absorption?
Movement of drug from site of administration into the blood stream, with the rate dependent on the physical characteristics of the drug and its formulation
How can drugs be absorbed?
By passive diffusion (lipid, aqueous), active transport, facilitated diffusion
What is the affect of pH on drug absorption?
Only non-ionized forms are sufficiently soluble to cross cell membranes. So the ratio of ionized to non-ionized forms of a drug at a particular pH influences absorption rate
What is drug distribution?
Movement of drugs from circulation into tissues and organs
What factors affect drug distribution?
Ionization- non-ionized forms sufficiently soluble
Lipid solubility- higher lipid solubility (nonpolar) = more distribution
Organ blood flow- drugs are rapidly distributed into highly perfused tissues
Plasma proteins- (weak acids bind to albumin, weak bases bind to lipoproteins, glycoproteins, globulins) The extent of binding is dependent on the affinity of a drug for protein-binding sites
Molecular size- large molecules cannot easily distribute across membranes
What is drug biotransformation?
Enzyme catalyzed conversion of drugs into metabolites; inactivate and detoxify to help facilitate the ability to leave body
What processes are responsible for the decline of plasma drug concentration over time?
Biotransformation (metabolism) and excretion
clearance
measure of rate of elimination
What is first pass biotransformation?
Drugs that are absorbed from the gut reach the liver via the hepatic portal vein before entering the systemic circulation. Many drugs are extensively converted to inactive metabolites during their first pass through the gut wall and liver, and have low bioavailability after oral administration
Phase I Biotransformation
Includes oxidative, hydrolytic, and reduction reactions. The drug becomes water soluble or inactive. In many cases, phase I enzymatic reactions create or unmask a chemical group required for a phase II reaction. In some cases, however, drugs bypass phase I biotransformation and go directly to phase II.
Phase II Biotransformation
Drug molecules undergo conjugation reactions with an endogenous substance. Conjugation enzymes join various drug molecules with one of these endogenous substances to form water-soluble metabolites that are more easily excreted. Most conjugated drug metabolites are inactive
microsomal cytochrome P450 (CYP) monooxygenase system
Family of enzymes that catalyze the biotransformation of drugs with a wide range of chemical structures
The CYP reductase mechanism for drug oxidation
Four steps are involved in the CYP reaction. First, the drug substrate binds to the oxidized form of P450 (i.e., Fe 3+ ). Second, the drug P450 complex is reduced by CYP reductase, using electrons donated by the reduced form of nicotinamide adenine dinucleotide phosphate (NADPH). Third, the drug-reduced form of P450 (i.e., Fe 2+ ) interacts with oxygen. Fourth, the oxidized drug (metabolite) and water are produced.
How can drug metabolism be altered by inhibiting/inducing CYP isoenzymes?
Enzyme inducers stimulate the production of CYP enzymes which increases capacity for metabolism-> drug is metabolized quicker. Thus drug concentration and effect are decreased
Enzyme inhibitors decrease the ability of binding. Drug concentration and effect are increased. Toxicity may ensue
