Unit 1 Flashcards
Why do dental hygienists need a working knowledge of pharmacology
- obtain a good health history with regards to drug history
- know which drugs are used in dentistry
- assist in emergencies
- explain medications to patients including herbal supplements
- recognize side effects of medication
- planning appts - diabetes, premeds - hman needs
- part of being a well rounded indibidual
Define chemical name
chemical structure code name given during initial production
Define trade or proprietary name
chosen by the registering company
name is protected for 20 years
Define generic name
the official name (nonproprietary, approved) which is capitalized - after 20 years companies may market generic name
Define chemical equivalent
meet the chemical standards of a drug
Define biological equivalent
create similar concentrations of the drug in the blood
Define therapeutic equivalent
create equal therapeutic levels in clinical trials
List reputable resources a DH could use to access current trug information
RxTx - not specific for dentistry
Health Canada
Lexicomp: Drug Information Handbook
Mosby: Dental Drug Reference
How are drugs regulated in Canada
scheduled drug regulations: The National Association of Pharmacy Regulatory Authroties (NAPRA) uses a drug scheduling model which reflects the risk to the public and establishes the level of professional control required
Who can prescribe in BC
Hygienists may write a prescription but a dentist/physician must sign
What information must be included in a prescription?
- date
- patients first and last name, birthdate and personal health number
- drug name (generic)
- drug strenth with unts
- drug dosage form and specify if sustained release
- quantity and/or duration of therapy
- directions for the patient (can no longer write as needed)
- refills if permitted
- physicians/dentists printed name, registration number and signature
What is the purpose of the Canada Vigilance Program?
- collects and assess reports of suspected adverse reactions to health products marketed in Canada
- post market surveillance ensures Health Canada monitor the safety profile of health produce once they are marketed
- information collected is on Health Canada and often RxTx
- reporting can be online, by phone or by email and fax
Define pharmacodynamics
actions of drugs on the body what kinds of effects mechanism of action beneficial and adverse effects drug application
Define pharmacokinetics
study of how the drug enters the body, circulates, is changed itn
Define pharmacokinetics
study of how the drug enters the body, circulates, is changed in the body, and leaves the body (absorption, distribution and metabolism then excretion)
Define pharmacogenomics
study of how genetics affects the pharmacodynmaics and pharmacokinetics of the drug and thus the selection for individual patients
What is the mechanism of action of drugs to exert an effect?
- fundamental principle is that drugs must interact with a molecular target (receptor) to exert an effect
- many receptors are proteins found on cell membranes or inside the cell
- molecues are activate/inhibit receptors are called ligonds - hormones, neurotransmitters, cytokines or growth factors
How doe the ‘law of mass’ apply to drug therapy
- combinations of the drug and receptor depends on the concentration of each
- the amount of drug-receptor complex determines the magnitude of the response
- a minimum (threshold) number of drug-receptor complexes must form to initiate response
- as drug concentrations increase, # of drug-receptor complexes increase therefore increasing drug effector
- a point occurs when receptors are bound (saturation) and response cannot increase further
What factors can impact drug-target interaction?
- drug binding controls the strength, duration and type of drug-receptor interaction (also known as the affinity - size and shape, types, # and special relationship; bonds - Van der Waals, hydrogen & covalent bonds)
- selection of drug response (greater affinity for once receptor, the more selective a drug action will be therefore decreasing side effects; increase affinity and efficacy = smaller amount of drug needed)
- tissue distribution of receptors: only tissues with receptors will response therefore the more restrictive the distribution of receptors = the more selective a drug
- activation of the molecular target (amplification can occur - when the D-R bond intitiates other reactions which can potentiate the drug effect)
- once distributed to the site of action, drugs either mimic or block therefore either speeding up a reaction or retarding the action - does not come in and do anything different
Define an agonist
- mimics
- binds to receptor, produces the maximum activation of the receptor and maximum effect
Define antagonist
- blocks
- binds to receptor but does not produce activation
Define partial antagonist
-binds and produces weaker activation of the receptor and subsequent downstream effects
Define inverse antagonist
- inhibits rather than activates the receptor
- can function like an antagonist however some diseases cause changes to the receptors
- with suppression rather than blocking being a more favorable response (chemotherapy)
- competitive
- change receptor
Define chemical antagonist
- do not act on the receptor but rather there is a chemical reaction with a target endogenous substance
- eg. antacids for heartburn - neutralize gastric acids
Define physiologic antagonist
- substances that create opposite effects
- eg. histamine and epinephrine
Define competitive reversible
-binds to receptor but produces no effect
Define competitive irreversible
-strongly binds ‘permanently’ reducing the number of receptors available
What is a dose/effect curve
indicates the increasing effect of a drug over the dose
-when the line flattens, it is the maximum response
What is the log dose effect curve?
-as the dose increases, the effect is 0, then a small effect (variable), and finally the effect is quickly increases which is the therapeutic range. Again, when the curve flatlines, it is the maximum response
What is ED50?
effective does where 50% of the patients responded
What is EDmax
all patients response - efficacy
What is TD50
50% of patients show toxic effect
What is LD50
50% of people died
Define potency
function of the amount of drug needed to produce an effect (potency and efficacy are unrelated!)
Define efficacy
maximum intensity of effect or response that can be produced by a drug
-how effective is that drug’s ability to achieve desired effect
(potency and efficacy are unrelated!)
What are advantages of enteral (oral or via the GI tract) administration?
- least expensive
- safest
- slowest onset
- most convenient though requires greater patient cooperation
What are disadvantages of enteral (oral or via the GI tract) administration?
- absorbed in GI therefore nausea and vomiting can occur
- require greater patient cooperation
- amount absorbed is less predictable
- rectal = poorly and irregularly absorbed, creams, gels and enemas
what are parental ways of administering pharm?
- injection
- topical - usually for local effects
- inhalation - metered doses, quick onset, no needles
What type of injections are available for pharm?
- IV
- IM
- subcutaneous
- intradermal
- intrathecal
- intraperitoneal
What are some disadvantages to using transdermal patches
skin acts as a barrier therefore require increased concentrations