Lecture 4 - Sept 30

Question 1

How are drugs named

Answer 1

1. By effect:
   -common to classify drugs by what they do (ex blood thinner)
   -this naming system tells you nothing about mechanism, side-effects or drug interaction
2. By precursor
   -classification of drugs based in what they are derived from
   -may or may not be accurate in predicting a drugs effect
   -ex opioids (derived from opium poppy which all behaviour similarly) vs eicosanoids (derived from arachidonic acid with an aviary of effects)
3. By receptor (best way to describe)
   -refers to type of receptor that drug occupies and its action at that receptor
   -ex BENADRYl blocks histamine receptors

Question 2

slide 4

Answer 2

-study chart in module
-prostaglandins are made from arachidonic acid (AA)
-recruitment of platelets, vasoconstriction, inflammation, uterine contractions, production of mucus in GI tract
-said we don’t need to know whole chart but should know: arachidonic acid gets converted to prostaglandins

Question 3

antipyretic (by effect)

Answer 3

Antipyretic - against fire, reduces fever: ex acetaminophen/tylenol
-during the inflammatory process, leukocytes produce endogenous pyrogens (such as prostaglandin e) in CNS, and that prostaglandin e goes to hypothalamus to cause an increase in body temp to help kill off pathogens. Tylenol blocks that activity so there is no temp increase. Tylenol has so intigmaltory properties but is better for fever

Question 4

anti-inflammatory (by effect)

Answer 4

Anti-inflammatory: against inflammation: ex ASA/aspirin, ibuprofen/advil/motrin
-work at COX 1 and 2 and inhibit the activity of them to stop production of proinflammatory prostaglandins
-low does of aspirin (81mg) is more inhibitor of cox 1 for preventing platelet aggregation, medium dose inhibits cox 2 for anti inflammatory and pain reducing effects, high dose inhibits all prostaglandins and leukotrienes do more of anti inflammatory effects

Question 5

analgesic (by effect)

Answer 5

Analgesic - without pain: ex aspirin and ibuprofen
-prostaglandins are blocked so they don’t signal pain receptors and anti inflammatory processes
-acetaminophen can do this as well, but as it lacks anti inflammatory abilities it’s not as good
-by inhibiting prostaglandin production, NSAIDs can also desensitise nerve endings

Question 6

antibiotic (by effect)

Answer 6

Antibiotic - against life: ex. Penicillin, ciprofloxacin - kills organisms

Question 7

antifungal (by effect)

Answer 7

Antifungal - against fungus: ex. miconazole/monistat - kills fungus/yeast

Question 8

anaesthetic (by effect)

Answer 8

Anaesthetic - without sense: ex. Lidocaine - removes feeling, can be local or general

Question 9

antiemetic (by effect)

Answer 9

Antiemetic - against vomiting: ex dimenhydrinate/gravol, doxylamine/diclectin, diphenhydramine hydrochloride/benadryl

Question 10

oxytocic (by effect)

Answer 10

Oxytocic - swift labour: ex. oxytocin/pitocin, ergonovine maleate - causes uterine contractions

Question 11

cervical ripener (by effect)

Answer 11

Cervical Ripener: ex prostaglandin e2 (dinoprostone, prepidil, cervidil) - causes cervix to soften

Question 12

Classification by Precursor (where they came from):

Answer 12

-eicosanoides (prostaglandins, leukotrienes, thromboxanes) are derived from eicosapentaenoic acid (arachidonic acid)
-sya little about the effects of eicosanoids - highly variable

-opiates are drugs derived from the opium poppy
-ex. Heroin, morphine, codeine

-Opioids are drugs that work on the same receptors as opiates but are not derived from opium (often used for pain relief) - can be called narcotics
-ex hydrocodone oxycodone
-the tem opioid is often used to denote any natural or synthetic drug that acts similarly to opium

Question 13

classification by receptor

Answer 13

-ex. = beta blockers or antihistamines
-a very common and useful way of classifying drugs is to look at the receptors the drug occupies and whether the drug stimulates or blocks the receptor

-drugs can be agonists - sits in receptor and has same effect as the natural ligand

-drugs can be antagonist - drug blocks the receptor
-this classification system works for most drugs because almost all drugs have receptors

-

Question 14

cell surface receptors

Answer 14

cell surface receptors:
-adrenergic receptors are G protein-coupled membrane receptors that bind adrenaline/noradrenaline
-beta agonists work ar beta-adrenergic receptors
-beta-blockers block the beta-adrenergic receptors treating heart arrhythmias, hypertension, etc

Question 15

soluble intracellular proteins/receptors:

Answer 15

-NSAIDs: cyclooxygenase inhibitors block the COX enzymes inside platelets

Question 16

Drug Nomenclature:

Answer 16

-there are numerous names for all drugs depending on who is naming the drug:

Chemical name:
-chemical names are all defined by IUPAC (international union of pure and applied chemistry)
-very rigid system

Generic name:
-an exclusive chemical name and the name in which it is listen in major pharmacopoeias, ex acetaminophen

Brand name:
-a name given to a drug by its manufacturer, usually designate as trademark, usually capital
-different brands have different fillers
-ex TYLENOL

Question 17

Components of a Drug Label:

Answer 17

1.Brand name
2.Generic name
3.Strength of medication
4.Form of medication (tablet, capsule, liquid) and quantity
5.Expiration date (how long medication will remain stable and safe to administer)
6.Lot number (manufacturers’ acth series that the mediation came from)
7.Manufacturer (pharmaceutical company the produced the medication)

Question 18

routes of administration

Answer 18

-path of which a drug (or other substance) is taken into the body - how it gets in

-enteric = drugs enter body via GI tract

-parenteral = mode of entry that does not involve the GI tract

Question 19

enteral routes

Answer 19

-enteric = through interests
By mouth = PO (per os)
Rectally = PR (per rectum)

Oral Administration (PO):
-majority of drugs given orally: easiest route, most convenient and economical
-often safest route due to slowness of effect (slow absorption and distribution)
-exceptions: alcohol and aspirin are absorbed very quickly through stomach
-exposed to low pH of the stomach and digestive systems = ex. Oxytocin, domperidone
-bioavailability of enterally administered drugs can be greatly decreased by first pass alteration (liver)
-mostly absorbed in small intestine

Rectal Administration (PR)
-well absorbed though rectal musce
-50% of drug will be exposed to liver and the 1st pass metabolism because the venous drainage of distal part of large bowel does not go to live
-common when not appropriate to take drug orally
-ex nausea and vomiting, babies and small children who cannot swallow oral medication, unconscious
-most common formulation for PR is the suppository
-ex GRAVOL (antibiotic and antihistamine) suppository is dimenhydrinate suspended in a solid, inert base of polyethylene glycol, silicon dioxide and titanium dioxide
-medicated enemas (not so common now but can give pain meds this way after caesarean or severe vomiting)

Question 20

read 81-83 drug fomrulations for enteri use
see common errors and drug fromulaiosn doc under filees, requried readings teams

Question 21

Parenteral Administration:

Answer 21

-routes of drug administration that bypass the GI tract
-include intraocular, intravaginal, transdermal, sublingual, injections, inhalation, intranasal

-pros: good for drugs that are unstable in GI tract (insulin, oxytocin) or poorly absorbed by GI tract (unconscious client in emergency, vomiting person, bypasses first-pass metabolism)

-injectable parenteral routes: IV, IM, ID, SC
-avoid GI barrier, avoid 1st pass metabolism

Question 22

-sublingual (SL) and buccal
parenteral routes

Answer 22

-sublingual (SL) and buccal

-even though the medication goes in the mouth is is not entirely admitted (is not swallowed to go through intestines, but is absorbed directly through oral mucosa) -examples = nitroglycerine taken sublingually and absorbed directly through mucosa, misoprostol

Question 23

inhalational adminsitration
parenteral routes

Answer 23

-inhalation administration
-rapid abortion due to large vascular surface area of lune
Ex = ENTONOX a mix of nitrous oxide and oxygen, also bronchodilators which as selective beta 2 adrenergic agonists powder with compressed fluorocarbon used as a propellant and sorbitan trioleate (an ould) used as dispersing agent
-hard to control dose of inhaled gases but metered doses of aerosols can give very accurate delivery of a drug
-prolonged use of this route may produce irritation of pulmonary epithelium (ex pure O2 given for 7-8 hours will cause tracheobronchial irritation)
-some inhaled drugs are given intranasally and are absorbed through the nasal music (ex phenylephrine HCI DRISTAN)

Question 24

intramuscluar injectins IM
parenteral routes

Answer 24

-usually administer low volumes of drugs in neutral pH
-allows for slower distribution of drugs than IV (5-15 min)
-can inject drug in aqueous solution – carbetocin for pph has rapid absorption
-can inject in oily (non aqueous) solutions (vehicles)
-as vehicle dissolves out of muscle, drug precipitates at site of injection, then starts to diffuse slowly → so can be gradually released over one or many weeks
-ex depo-provera is the same drug as provera, medroxyprogesterone acetate (progestin_ but depo-provera is given IM instead of PO (depo provera given as contraceptive will last about 3 months)
-vitamin k (phytonadione) injection given to newborns

Question 25

subcutaneous sc injections
parenteral routes

Answer 25

-referred to as sub-q
-good for small volume of drug: not irritating
-injection into the fatty subcutaneous tissue
-allows for a slower absorption into the bloodstream (slower than IM and IV) → ex. Insulin (diabetes mellitus therapy) is given SC in order to slow and lengthen effect

Question 26

intravenous injections IV
parenteral outes

Answer 26

-drug absorption is immediate by this route → drug goes directly into venous blood for rapid effect
-easier to get an accurate blood level as the factors in the GI system and liver do not affect absorption
Adverse reactions (like anaphylaxis) more likely since high concentrations of drugs may be attained rapidly in both the tissue and plasma so constant monitoring is necessary
→ ex pitocin or syntocinon (uterine stimulant) is the peptide hormone oxytocin which cannot be taken PO since it will be digested and so given by continuous IV infusion
-IV bolus - large volume of fluid or dose of a drug given intravenously and rapidly at one time

Question 27

Intradermal Injections ID:
parenteral

Answer 27

-into the skin, but not all the way to the subcutaneous tissue
-ex sterile water intradermal injections can be used to block lower back pain
-ex. Tests for mycobacterium tuberculosis, the causative agent of TB are done by intradermal injection

Question 28

Intra-arterial Injections:
parenteral

Answer 28

-uncommonly (or accidentally) drugs are injected into arteries
-allows direct and immediate dosing of a particular tissue which is fed by the artery injected (ex cancer therapy drugs or radio imaging isotopes)

Question 29

Intraosseous Injections:

Answer 29

-an alternative route to umbilical vein catheterization -NRP
-intraosseous infusions go directly to the bone marrow of the tibia

Question 30

slides 26-28 on injection angles

Question 31

Intro to Legislation:

Answer 31

-outline in the midwifery act 1991
-ontario regulation 188/24: designated drugs and substances
-this legislation outlines:
The prescription drugs ontario midwives can practise/order/administer in their own (includes how and were some of those meds can be given)
That Ontario midwives may use/administer ANY drug on the order of a member of the College of Physicians and Surgeons of Ontario and/or on the order of a member of College of Nurses of Ontario who hlds an extended certificate of registration (ex. Nurse practitioner)
That ontario midwives may order/prescribe/administer any drug that may be lawfully purchased without a prescription

Question 32

slide 29

Question 33

Safe Prescribing and Administration Practice:

Answer 33

-it can be difficult for any type of clinician to feel confident in treatment decision, given the huge number of available options
-model for decision making to help structure your thoughts/gather information
-several options available
-WHO 6 step model of rational prescribing

Question 34

WHO 6 step model of rational prescribing:

Answer 34

1.Define problem (symptoms, lab results)
2.Specify therapeutic objective
3.Treatment choice
4.Start treatment
5.Give info, instructions and warnings
6.Monitor (and stop?) treatment