Prescribing basics
Prescribing is regulated by state BON
Proper RX
Providers name and address, Telephone
DEA
Pt name/DOB/Addres
Name of Drug,
... [Show More] strength, SIG(directions) with indication/Route and frequency, Quantity and signature.
Drug Schedules: Most addictive to least
1: Heroin,LSD, MJ
2: hydrocodone, cocaine, Methamphetamine, methadone, oxycodone, meperidine, fentanyl, adderall, ritalin
3: codeine, ketamine, testosterone
4: xanax, valium, soma, ambient, tramadol
5: antidiarrheal, antitussives, lomotil, lyrica
Pharmicodyamics
The effects of drug on the body. Receptors are large molecules usually proteins, that interact and mediate the action of drugs
agonist
produce receptor stimulation and a conformational change every time they bind. Do not need all available receptors to produce a maximum response
Partial agonist
drugs that have properties in b/w those of full agonist and antagonist. They bind to receptors but when they occupy the receptor sites, they stimulate only some of the receptors.
antagonist
drugs with affinity for a receptor but with no intrinsic activity. Affinity allows the antagonist to bind to receptors, but lack of intrinsic activity prevents the bound antagonist from causing receptor activation. The block action of drugs (ex. Narcan)
Bioavailabity
% of administered dosage of the drug that survives the first pass through the liver and reaches the blood stream
half life
Time required for the amount of a drug in the body to decline by 50%, drugs with shorter half lives must be administer frequently. 4.5-5.5 times the half life to get steady state and to be limited from the body
what the body does to the drug
absorption, distribution, metabolism, excretion
Distribution
movement of absorbed drug in bodily fluids throughout the body to target tissue. Properties affecting: lipid/water solubility, PH affects ionization of drug, protein binding, size of molecule (smaller molecules are more able to diffuse)
Tissue: fat, bone, blood/brain barrier (only lipid soluble will pass), placental barrier (many drugs can pass)
Protein binding
unbound drug is free which is active, crosses membrane. Low plasma proteins result in more free drug. Competition: when 2 highly bound drugs are given it increases the level of both drugs
Metabolism
take place in the liver mostly. Chemical change of a drug structure to:
Enhance excretion, inactivate the drug, increase therapeutic action, active a prodrug (inactive until metabolized in the body into the active compound, ex: levodopa), increase or decrease toxicity
CYP450
enzymes constitutes the most important of the phase I metabolizing enzymes (account for about 75% of drug metabolism in the liver)
Phase 2: conjugation reaction occur leading to large increases in hydrophilicity of the substrates rendering them more readily excretable
Substrate
an agent that is metabolized by an enzyme into a metabolite and product and eventually excreted
Inhibitors
compete with other drugs for a particular enzyme affecting the metabolism (decreased) of the substrate and decreases the excretion of the substrate and increasing the circulating drug
inducer
competes with other drugs for a particular enzyme affecting metabolism of the substrate (increases) decreasing the efficacy of the drug
excretion
renal: passive glomerular filtration, active tubular secretion, tubular reabsorption, gi tract, lung, sweat and salivary, mammary
genomics
study of the complete set of genetic information present in a cell, an organism, or species
pharmacogenetics
the study of the influence of hereditary factors on the response of individual organisms to drugs, and the study of variations of DNA and RNA characteristics as related to drug response
Pharmacogenetics tests
Mentioned on drug labels can be classified as "test required," "test recommended," and "information only." Currently, four drugs are required to have pharmacogenetics testing performed before they are prescribed: cetuximab, trastuzumab, maraviroc and dasatinib
wafarin, carbamazepine, valproic acid and abacavir are recommended to tests prior to initial dosing
Carbamazepine and Asisans
Initiating carbamazepine therapy in these patients (allele HLA-B*1502) are at high risk for developing Steven Johnson syndrome or toxic epidermal necrolysis (TEN)
The ability of the anesthetic to penetrate the axon membrane is determined by 3 properties. What are they?
Molecular size, Lipid solubility, degree of ionization at tissue pH [Show Less]