PHARM - Test 1 (CNS, Routes of Entry, Medical Math, Generic vs Trade) Flashcards
ac
before meals (ante cibum)
bid
twice a day (bis in die)
cap
capsule
d
d (24 hours)
Exlir.
liquid or syrup
g
gram - dry measure used in tablets
gr
grains - dry weight of medication
gt
drop (gt means “guttae”)
h
hour
hs
at bedtime (hora somni)
IM
intramuscular
mg
milligram - dry weight measure
mL
milliliter - liquid volume measure
PO
“per os” - by mouth
pc
after meals (post cibum)
pil
pill
prn
as needed (pro re nata)
q
every
q2h
every 2 hours (quaque 2 hora)
qd
every day (quaque die)
qh
every hour
Sig
patient instructions (“write”) - signa
qid
4 times a day (quater in die)
Supp.
medications inserted rectally (“suppository”)
Ṫ
one tablet
tab
tablet
tid
3 times a day (ter in die)
U
Unit
brand name
the trade name of a drug; created by pharmaceutrical companies so that they are able to make money off of the drug
Tylenol is a (brand/generic) name
Acetaminophin is a (brand/generic) name
brand
generic
Prior to a drug arriving on shelves, what processes does it have to go through to ensure it is safe and effective?
1) pharmaceutical company conducts a series of lab studies (takes years)
2) studies are then performed at approved clinical research facilities across the country (drug is administered with strict protocols)
3) Food and Drug Administration (FDA) reviews lab and clinical trial findings, assesses manufacturing processes, and verifies drug’s purity, stability, and strength before approving medication
4) one FDA approved, given a brand name
True or False. The brand is protected by a patent so other drug manufacturers cannot copy the formula and duplicate the drug.
True. Other drug manufacturers can buy the generic formula but cannot sell it under the same brand name (but once the patent has expired)
True or false. Other pharmaceutical companties may apply to the FDA for permission to manufaacture and sell a generic version of the original compound once the original patient expires.
True
When developing a generic drug, what must the manufacturers ensure is kept the same as the original brand name drug?
- same active ingredient(s)
- same form (liquid, pill, capsule, injectable, topical)
- concentration
- dosage
- as pure and stable as original drug
- same distribution patterns and be metabolized and eliminated from the body
True or False. Generic drugs can have different inactive ingredients such as preservatives or fillers along with the same active ingredients.
True
Trademark laws prevent generic drugs from looking just like the brand name drug, so the color and size may be different (or the product size like the number of capsules in the package may be different)
BUT THE ACTIVE INGREDIENTS WOULD BE ABSOLUTELY THE SAME (it’s the law)
Which are cheaper: Generic or brand name drugs. Why?
Generic - because they don’t have to do all that initial work of developing the drug so they’ve got their work cut out for them and don’t need to invest as much money in the first place. This means they can sell it at a lower cost and still make a profit
Generic drugs may cost 30-80% less than original versions
susp
suspension
How do you calculate medication dosage?
WANT/HAVE x quantity
WANT: the amount desired
HAVE: how much supply is on hand (amount per item of med that is available)
quantity: the form of medication (tablet, capsule, milliliter, etc.)
*notes: units must be the same (mL for mL, gr. for gr.) and medicate as per a patient’s WEIGHT not age
Dosage
the amount of medication to be given in one dose
John was prescribed Amoxicillin 500mg capsule po tid x 10d. The pharmacist’s supply includes 500mg per capsule. Provide the single dose, daily dose, and total amount that John needs to take.
Single dose: 1 capsule (500mg)
Daily dose: 3 capsules (1500mg)
Total amount: 30 capsules (15 000mg)
Maya the dog was prescribed Trazadone 750mg po qd x 10d. The pharmacist’s supply includes 500mg per scored tablet. Provide the single dose, daily dose, and total amount that Maya needs to take.
Single dose: 1.5 tablets (750mg)
Daily dose: 1.5 tablets (750mg)
Total amount: 15 tablets (7500mg)
Kyle was prescribed Digoxin elixir 150 mcg po tid x 10d. The pharmacist at the hospital has 50mcg/mL available. Calculate the single dose, daily dose, and total amount that Kyle needs to take.
Single dose: 3mL (150mcg)
Daily dose: 9mL (450mcg)
Total amount: 90mL (4500mcg)
Pharmacology
the scientific study of the effects of drugs and chemicals on living organisms
Drugs
any chemical or substance that is natural or synthetic that affects a biological system
Food and Drugs Act (FDA)
primary legislation governing the safety and nutritional quality of food an drugs sold in Canada
Role is to protect public against health hazards and fraud from the sale of food (and beverages), drugs, medical devices and cosmetics
Scope of Food and Drug Act (FDA) (10):
- food labelling
- advertising and claims
- food standards and compositional requirements
- fortification
- foods for special dietary uses
- food additives
- chemical and microbial hazards
- vet drug residues
- packaging material
- pesticides
Controlled substance
drug/chemical whose manufacture, posession, or use if regulated by a government (such as illicitly used drugs or prescription medications that are designated by law)
Prescription Drugs
medications that need supervision (i.e. prescription label on how to ake the medication) or those that are at risk of being misused or abused
True or False. Over the counter (OTC) meds can be just as dangerous as prescribed ones.
True
The most common OTC medication used is:
tylenol
All drugs at least ____ names. They are __________ and ________ name.
two; generic vs brand/trade name
True or False. Trade names will only start with lowercase letters.
False. Always starts with capital letter
The category of drugs with nonproprietary names is known as
generic drugs
True or false. Generic drugs usually are an abbreviated version of the drug’s chemical name and is registered wth the FDA.
True
True or False. Insurance would always cover the cost of the brand name drug even if the generic drug is available, as long as the patient requests the brand name.
False. Generic drugs are normally always covered, but brand name drug is only covered by insurance if no generic form exists
What is the difference in FDA approval re: inactive ingredients in brand vs generic name?
Brand name: inactive ingredients are tested and approved by the FDA
Generic: may differ - but proven to be acceptable by the FDA (such as the coating on easy swallow drugs)
Drugs that are standard in size, color, and packaging fall under the which category of drugs (brand/generic)?
brand name
Paramedics carry (generic/brand name) drugs.
generic
OTC medications also have generic counterparts. Provide the generic name for the following OTC medications.
a) Aspirin
b) Benadryl
c) Gravol
d) Advil (NSAID)
a) Acetylsalicylic Acid
b) Diphenhydramine
c) Dimenhydrinate
d) Ibuprofen
What are the 5 rights of drug administration?
1) Drug - is this the right drug?
2) Dose - is this the right dose?
3) Route - is this the right route?
4) Time - is this the right time?
5) Patient - is this the right patient?
What are the 7 routes/categories of entry for drugs?
1) oral
2) nasal/intranasal
3) sublingual/buccal
4) transdermal/topical
5) rectal/vaginal
6) inhalation
7) parenteral IM, IV, SQ
The #1 route of entry for medication is:
orally
Oral route of entry
- Taken by mouth through the alimentary (GI) tract (the ACTUAL act of swallowing not just putting it in your mouth - see other forms of entry such as sublingual)
- must travel to stomach before being broken down
- absorbed in intestine and passed into the blood stream
Onset time for oral method of drug administration
20-60 minutes
*note: this can change with factors such as stomach contents (i.e. milk can coat your stomach so decreased absorption; empty stomach means faster absorption because less things to fight for its efficacy)
Enteral medications
meds that are absorbed through the GI tract
Nasal vs intranasal drug administration route
Nasal: through the nose in the form of drops or gels
Intranasal: the use of aerosols
Why are powder forms of drugs not prescribed and not an acceptable form of route of entry?
Because drugs can be extremely acidic/basic and will burn mucosa lining
Onset time of Nasal/Intranasal route administration
~10 min (5-15 min range)
Sublingual/Buccal
Sublingual: under the tongue
Buccal: between cheek and teeth
Onset time and peak effect time for sublingual/buccal medications
Onset: quickly (~15 min)
Peak effect: 30 mins
How does sublingual/buccal medications get into the body?
Diffusion into the bloodstream from tissues under the tongue or side of the mouth (use of spray of dissolving tablet)
True or False. The effectiveness of medication taking sublingually/bucally can be altered if taken after large meals.
False. Sublingual/buccal routes of administration override enteral system
Transdermal route of administration
Medication is applied to the skin and enters circulatory system through diffusion
Instructing a patient to chew a baby aspirin and make it into a paste, and then place it under the tongue/between cheek and teeth is known as what route of entry for the medication?
sublingual/buccal
A patient with a nicotine patch is receiving medication via what route of entry?
Transdermal
Where are transdermal patches usually placed on the body. Why?
usually placed on chest or front of of shoulder because if it’s anywhere else, the chance of forgetting it increases (out of sight, out of mind). People may forget and continuously add on more patches which can increase risk of OD
What do transdermal controlled-release forms of medications do?
They are designed to release the drug for extended periods, sometimes for several days
Topical
A cream or gel applied to top layer of skin; usually short-lasting
Do topical drugs enter the circulation?
No. They just work at site of action
Rectal medications are also known as:
suppositories
Once in the systemic circultory system, drug distribution is influenced by _____________.
Tissue/organ blood flow
Rectal medications are typically in the form of:
tablet/capsule
onset time for rectal/vaginal route of drug entry
10-15 minutes (quick because ++vascular so east to get into bloodstream)
The number one route of medication administration for children is:
rectally
True or False. You can typically take all oral medications rectally/vaginally
True
*walls of vagina have the same cellular make up as esophagus so effect is similar
True or False. Medications for sex organs can be administerd through the genitalia of males and females.
False. Vagina is the only genital that can accept medications for sex organs (penis does not work)
Vaginal medications are usually in what form?
cream or gel, but capsule and tablet can also be administered
Inhalation route of entry
via aerosol - works directly into respiratory system
Onset time/absorption rate for inhalation
immediately (within 5 min)
Parenteral IM, IV, SQ entry route
Injectable medications - directly into muscle (IM), blood stream (IV), or skin (SQ)
No GI first pass effect
What is hepatic metaoblism/hepatic first pass effect?
Phenomenon where the amount of a drug that is actually delivered to your general circulation is less than the total amount you initially took by mouth (due to having to pass through GI tract and then via portal vein into the liver where some drugs are metabolized)
Medications given IM, IV, SQ are known as ____________.
Parenteral medications
Which of the following work best with the quickest onset?
a) IM injections
b) IV injections
c) SQ injections
d) all are equal in onset time
b) IV injections - directly into blood stream; effect is almost immediate
Pharmokinetics
refers to how a medication acts, how it is moved through the blood stream (absorption, distribution, biotransformation, and excretion)
Pharmacodynamics
How a drug works and interacts with other drugs and various receptor sites within the body
adverse effect vs side effect
Adverse effect: an undesirable/unintended pharmacologic effect resulting from a medication or intervention that has been administered correctly. Mild, moderate, or severe
Side effect: a secondary unwanted effect that occurs with taking a medication/drug therapy
True or False. All medications have an adverse effect
True
Re: pharmacokinetics, the goal of drug therapy is:
to obtain a desired clinical effect while minimizing the likelihood of an adverse effect
Rule of First Order Kinetics
constant fraction (%) of medication is absorbed into the blood stream per unit of time
- 50% and 50% waiting (think half life)
- applies to every route of entry EXCEPT IV
Zero order Kinetics
100% of the medication is absorbed in the brief period of administration
What are the 4 methods that medications are absorbedinto the body’s various membranes (cellular level)?
1) passive diffusion
2) carrier-mediated facilitated diffusion
3) active transport
4) endocytosis
Passive diffusion
chemicals moving from high to low concentration across a semi-permeable membrane without expenditure of energy
ex. structure of blood placenta barrier
Carrier-mediated Facilitated Diffusion
PASSIVE TRANSPORT - movement of molecules/drug components across cell membrane via special transport proteins that are embeeded within cellular membrane
ex. structure of blood brain barrier
Active transport
movement of drug molecules across a cell membrane from lower to higher concentration (against the concentration gradient) - energy required
Endocytosis/Phagocytosis
cell forming a sac around a drug molecule with the cell’s membrane, which is then folded inwards bringing the drug into the cell (via drug receptors)
What are the two major proteins in plasma that are responsible for binding of most drug compounds in the systemic circulation?
albumin
alpha-acid glycoprotein
Metabolism/Absorption
breakdown and changing of a drug by various chemical reactions throughout the body
typically happens in liver, lungs, and kidneys
Biotransformation
process of breaking down an active drug into an inactive compound (*inactive compound is still potent, just doesn’t get used)
The #1 method of excretion is through ______ for removal of drugs and durg byproducts. To a lesser extent, the _____ may also aid in elimination.
kidneys; liver
What substance transports byproducts to the gut to be excreted?
bile
True of False. Excretion can be done through urine, feces, sweat, and lactating breast milk
True
What potential problems may occur with inappropriate excretion of drugs/drug byproducts?
may lead to kidney damage (those with urinary retention)
accidental OD (those with constipation that cannot pass the drug byproducts)
What are the 3 mechanisms describing how drugs work in the body (i.e. interactions)
1) drug receptor interactions
2) drug enzyme interactions
3) non-specific drug interactions
Drug receptor interactions
Also give an example
When the drug is introduced to the cell, starts working. When removed, the effects of the durg on the cell also stops.
Reversible binding, no change in cellular structure
Eg. morphine IV for pain
Drug Enzyme Interactions
give an example
Enzyme is the drug target. When drugs interact with enzymes and will either increase or decrease the enzyme mediated chemical reactions (making substrate/metabolite)
an irreversible change
ex. ASA overdose causing increased liver damage even after drug is removed/metabolized
Therapeutic index
a quantitative measurement of the relative safety of a drug (a comparison of the amount of a therapeutic agent that cause the therapeutic effect to the amount that causes toxicity)
ex. when it says don’t take more that _____ in a 24 h period due to toxicity concerns beyond that
Non specific drug interactions
give an example
occurs when drug acts on a target organ or tissue in a way that does not require binding to a receptor/enzyme
no change to cell structure
eg. neutralization of stomach acids by antacids
Describe the following interactions between food and drugs:
a) food’s effect on drug side effects
b) taking meds at the same time as food
c) milk
d) grapefruit juice
a) food can enhance side effect profiles of many drugs
b) meds + food at the same time can cause your body not to absorb the meds
c) milk coats the stomach and can change a drug’s absorption
d) grapefruit juice adverses many cardiac drugs (cardiac glycoside) - may lead to toxicity
True or False. The dose required to produce the desired result does not depend on route since it’s going to end up in your system regardless.
False. Dose required DOES depend on route
Increasing the dose of a medication increases the physiological effect - up until a point where an increase in dose will not result in any further increase in disred physiological effect. This is called __________ and can be demonstrated on a graph known as ____________.
ceiling effect
drug response curve
Modifying factors of drug dosage
- age
- body weight
- time of administration
- route of administration
- excretion routes
- hepatic or renal failure
*note that a toxic dose is also dependent on weight
What is dosage form?
The physical form of a dose of drug (tablets, capsules, creams, ointments, aerosols, and patches)
Affinity vs Efficacy
Affinity: ability for a drug to bind to its receptor
Efficacy: ability for the drug to evoke a response after binding to its receptor
True or false. A drug can have no affinity/efficacy, have either or, or have both affinity and efficacy.
True
A drug that has high affinity but no efficacy can be labeled as:
antagonist - purpose of binding to receptors to block them and not allow further activation of receptors
A drug that has high affinity and high efficacy is known as:
agonist - can be used to activate receptors to evoke a response
True or False. CNS and PNS are always constantly working together to balance each other
True
Briefly describe how a drug would make its way down to the foot (target action site)
Drugs go through blood via CNS and travel through the main “central highway” (aka the spinal cord) ⇒ branches off to PNS and then goes where it needs to go to bind to the local receptors
Which nervous system division is “arousing”? Describe physiological changes that occur when this system is primarily activated.
Sympathetic NS
- Pupil dilation
- increased HR
- inhibits digestion
- stimulates glucose release by liver
- stimulates secretion of E, NE, cortisol
- relaxes bladder
- stimulates ejaculation in male (& preparation of sex)
Which nervous system division is “calming”? Describe physiological changes that occur when this system is primarily activated.
Parasympathetic NS
- contracts pupils
- slows HR
- stimulates digestion
- stimulates gallbladder
- contracts bladder (to tell you to pee)
- allows blood flow to sex organs - you cannot ejaculate/orgasm unless parasympathetic NS kicks in
- decreased glucose release
- calms liver
- ACh release
Name the divisions of the nervous system and their subdivisions.
CNS vs PNS
CNS: receives and processes information, initiates action
PNS: transmits signals between the CNS and the rest of the body
PNS functional divisions: Motor neurons vs sensory neurons
Motor neurons: carry signals from CNS that control activities of muscles/glands
Sensory neurons: carry signals to the CNS from sensory organs
Motor neuron division of PNS is further divided into:
Somatic Nervous System: controls voluntary movements by activating skeletal muscles
Autonomic Nervous System: controls involuntary responses by influencing organs, glands, and smooth muscle
Sympathetic and parasympathetic division branch from what nervous system? Briefly describe sympathetic vs parasympathetic
ANS
Sympathetic Division: prepares body for fight or flight (stressful or energetic activity)
Parasympathethic Division: dominates during times of “rest and relaxation”; directs maintenance activities
Sympathetic division has ___________ receptors while parasympathethic dividion has ____________ receptors.
adrenergic; cholinergic
Adrenergic receptors branch off into:
alpha (a-1 and a-2) and beta (b1 and b2) receptors
Cholinergic receptors branch off into
nicotinic and muscarinic receptors
Somatic Nervous System (SoNS) innervates part of what system?
What are the two main functions of SoNS?
- innervates part of sympathetic NS
Two main functions: skeletal movement and reflexes
- carries information via nerve fibers to the brain and spinal cord
- voluntary control of body movements via skeletal muscles
- reflexes: lash, patellar, touching a hot stove and reflexively pulling away (occurs when you are not mentally preparing for it), falling
True or False. SoNS has nociceptors.
True
Nociceptors
- pain receptors found all over body and act as injury prevention (especially in muscle fibers)
- activated in response to potentially damaging stimuli (heat, cold, extreme forces)
- prevents us from hyperextending joins, overstretching msucles and protects from other injuries
- more found in feet (so more sensitive to pain stimuli)
Toxic Dose
a dose that will cause death; a poisonous amount of a drug
Half life
the time required for the concentration of a drug in the bloodstream to drop to half of its original level (this is when the medication has reached its peak and will now start to have reduced effect)
Onset of Action
referred to as the latent period (the time it takes for a medication to start working)
*Important to know for patient tx for meds with slower onset of action
Indication
use of a drug for treating a particular disease or condition of a patient
Duration of Action
amount of time a single dose of medication produces the desired effect (measured from the time the desired effect is first observed until it is no longer perceptible)
Peak Concentration
- the highest concentration of a drug in the blood, CSF, or target organ after a dose is given
- a pharmacokinetic measure used to determine drug dosing
Contraindication
a specific situation in which a drug should not be used or administered as it may be harmful to the patient
od
right eye (oculus dexter)
os
left eye (oculus sinister)
Four categories of adverse effects include:
Teratogenicity: the ability to cause defects in a developing fetus
Mutagenicity/Carcinogenicity: ability to mutate cell structure or cause cancer
Idiosyncrasy: happens for unknown reason
Drug dependance/addiction
Describe knee jerk reflex/response
COME BACK TO THIS AND FINISH IT
initial stimulus ⇒ stretch receptor in quad sends afferent impulses to spinal cord ⇒
Vital processes (HR, blood pressure, respiratory effect) are normally controlled by __________ and is (involuntary/voluntary)
Autonomic Nervous System; involuntary
Two divisions of ANS
sympathetic nervous system (SNS)
parasympathetic nervous systerm (PNS)
Determine which of the following is innervated by the sympathetic nervous system or parasympathetic nervous system, or both.
a) heart
b) vascular smooth muscle
c) sweat glands
d) bronchial smooth muscle
e) iris
f) salivary glands
g) urinary bladder
a) both
b) SNS
c) SNS
d) both
e) both
f) both
g) both
Describe the follow characteristics of somatic motor systems.
a) myelination of axon
b) number of neurons from CNS to effector organ
c) effector organ(s)
d) neurotransmittor at effector
e) effect: (stimulatory/inhibitory/both)
a) highly myelinated
b) single neuron from CNS to effectors
c) skeletal muscle
d) ACh
e) stimulatory (+)
Describe the follow characteristics of autonomic parasympathetic motor systems.
a) myelination of axon
b) number of neurons from CNS to effector organ
c) effector organ(s)
d) neurotransmittor at effector
e) effect: (stimulatory/inhibitory/both)
a) lightly myelinated preganglionic axons ⇒ unmyelinated postganglionic axon
b) singl eneuron chain from CNS to effector organs
c) smooth muscle, glands, cardiac muscle
d) ACh at pre-ganglionic axon and then ACh at post-ganglionic axon
e) stimulatory or inhibitory, depending on NT and receptors on effector organs
Describe the follow characteristics of autonomic sympathetic motor systems.
a) myelination of axon
b) number of neurons from CNS to effector organ
c) effector organ(s)
d) neurotransmittor at effector
e) effect: (stimulatory/inhibitory/both)
a) lightly myelinated preganglionic axons ⇒ unmyelinated postganglionic axon
b) two-neuron chain from CNS to effector organs
c) smooth muscle, glands, cardiac muscle
d) ACh at pre-ganglionic axon and then NE at post-ganglionic axon (this also occurs when pre-ganglionic axon directly stimulates the adrenal gland to release E and NE into blood vessel)
e) stimulatory or inhibitory, depending on NT and receptors on effector organs
Adrenergic agonists
medications that influence SNS using adrenergic receptors
Adrenergic antagonists
medications that block or inhibit the SNS adrenergic receptors
ex. epinephrine for anaphylaxis
_________ mimic SNS neurotransmitters as they are hormones that function as neurotransmitters. What 3 hormones within the SNS fall under this category?
Catecholamines
Examples: Epinephrine, Norepinephrine, dopamine
Adrenergic drugs
medications that simulate certain nerves and receptors in the body by:
a) mimicking the action of the chemical messengers E or NE
OR
b) by stimulating their release
*these drugs are used in many life-threatening conditions (cardiac arrest, shock, asthma attack, or allergic reaction)
Adrenergic agonists are also known as
sympathomimetics
Adrenergic antagonists are also known as
sympatholytics
Medications may manipulate these receptors in the sympathetic nervous system to manage heart rate, blood pressure, and respiratory effeort. What are these receptors?
alpha and beta adrenergic receptors
Chronotropic
changes in heart rate
A patient with SVT (high HR) would benefit from a (positive/negative) chronotropic medication
negative (decreases HR)
A medication that has a positive chronotropic effect would result in what?
increased HR
Inotropic
Changes in contractility (i.e blood volume/BP)
+ve inotropic vs -ve inotropic
+ve ionotropic: increases BP
-ve ionotropic: decreases BP
Dromotropic
changes in conduction (i.e. rhythm)
can be +ve or -ve ⇒ to help return to normal rhythm
The body’s natural production of sympathomimetic hormones include:
dopamine
norepinephrine
epinephrine
What effects do adrenergic drugs have?
- increase BP
- constrict blood vessels
- open airways leading to the lungs
- increase HR
- stop bleeding
Stimulation of alpha-adrenergic receptors on smooth muscles reuslts in what changes?
- vasoconstriction of blood vessels
- relaxation of GI smooth muscles (decreased motility)
- constriction of bladder sphincter
- contraction of uterus
- male ejaculation
- contraction of pupillary muscles of the eye (dilated pupils)
Stimulation of beta-1 adrenergic receptors on the myocardiu, AV node, and SA node result in what?
cardiac stimulation
- increased force of contraction (positive inotropic effect)
- increased heart rate (positive chronotropic effect)
- increased conduction through AV node (positive dromotropic effect)
Alpha 1 adrenergic receptors is located where?
What is its effect?
peripheral blood vessels
Stimulation results in vasoconstriction (/smooth muscle contraction) and elevation of systemic BP
How are alpha adrenergic receptors stimulated?
by norepinephrine mostly (and then epinephrine too)
How are beta adrenergic receptors activated?
predominantly epinephrine (and lesser extent, norepinephinre)
Stimulation of beta adrenergic receptors result in
smooth muscle relaxation
Alpha 2 adrenergic receptors are located where and what is their function?
- Location: nerve endings (presynaptic terminal)
- Function: provide negative feedback to nerves in SNS
- signals process when goal/target is reached
- leaads to vasodilation, decrease BP
Beta 1 receptors are located where and have what function?
- Location: found in the heart
- Function: when stimulated, increases HR and contractility, increases cardiac output
Beta 2 adrenergic receptors are located where and have what function?
- Location: bronchial smooth muscle (and uterus)
- Function: when stimulated, relaxes bronchial smooth muscles (opens airways); increases diameter of bronchial tree
Beta 1 blocker example
metoprolol
decreases both BP and HR therefore is a -ve chronotropic and ionotropic medication
Beta 2 blocker example
salbutamol
There are 3 mechanisms of drugs acting on receptors. They are:
1) Direct Acting Sympathomimetic
2) Indirect Acting Sympathomimetic
3) Mixed Acting Sympathomimetic
Direct Acting Sympathomimetic
Binds directly to receptor and causes a physiologic response
Indirect Acting Sympathomimetic
- causes a release of catecholamines (so other sympathomimetics) from other storage sites (vesicles) in nerve endings which then bind to receptors to cause a physiological response
Mixed Acting Sympathomimetic
- Directly stimulates the receptor by binding to it and,
- indirectly stimulates receptor by causing the release of stored NTs from vesicles in the nerve ending into the receptor site so that alpha and beta responses can be targeted together
The nervous system that performs the housekeeping chores of the body (eat, sleep, rest) and brings the body back to normal routine after events is known as:
parasmypathetic nervous system
Cholinergic agonists
medications that act on/influence PNS (mimic/enhance effect of ACh)
Cholinergic antagonists
medications that inhibit parasympathetic NS receptors
What are the two cholinergic receptors that are found within the SNS/PNS?
muscarinic and nicotinic
*note that muscarinic and nicotinic receptors are found within the sympathetic and parasympathetic nervous systems as they work both but are PRIMARILY parasympathetic driven which means they are mostly stimulated by acetylcholine
Atropine blocks muscarine receptors, inhibiting them. Thus, atropine is a:
a muscarinic receptor antagonist
Low dose ACh stimulates what receptors and causes what effects?
- stimulates muscarine receptors
- causes “WET” symptoms
- bradycardia
- bronchoconstriction
- increase in GI motility (wet stool, diarrhea)
- bladder constriction
- fall in BP
- salivation (which helps with vomiting)
- lacrimation (tearing - different than emotion induced)
High dose ACh stimulates what receptors and causes what effects?
- stimulates nicotinic receptors - high doses of ACh can trigger SNS
- causes “DRY” symptoms
- CNS stimulation
- ganglionic stimulation
- release of adrenaline
- rise in BP
Drugs that block or inhibit the actions of ACh in parasympathetic nervous system are known as:
anticholinergics
parasympatholytics
antimuscarinic drugs
Parasympathomimetic drugs
Drugs that mimic the action of ACh
Examples of anti-cholinergic drugs (4)
1) anti-psychotics
2) diphenhydramine (Benadryl) /gastrointestinal (dimenhydrinate)
3) parkinson’s medications
4) muscle relaxants
Anti-cholinergic drug effects
-
Cardiovascular:
- small doses would decrease HR; large doses increase HR
-
CNS: small doses would decrease muscle rigidity and tremors
- large doses: drowsiness, disorientation, hallucinations
-
Eyes: dilated pupils (mydriasis)
- Decreased accommodation caused by paralysis of ciliary muscles (cycloplegia)
-
GI: Relax smooth muscle tone of GI tract
- Decrease intestinal and gastric secretions
- decrease motility and peristalsis
- Respiratory: decrease bronchial secretions (dries up wet cough)
Where are nicotinic receptors found?
CNS, autonomic ganglia, striated muscle
Where are muscarinic receptors found?
cardiac smooth muscle, exocrine glands, brain
Anticholinergic toxidrome mneumonic
- Dry as a bone (dry mucous membranes)
- Hot as a hare (febrile (fever) - anhydrosis)
- Mad as a hatter (hallucinations/altered mental status)
- Blind as a bat (significant pupil constriction/dilation - mydriasis)
- Red as a beet (flushed skin)
Can’t see, can’t pee, can’t spit, can’t shit
Cholinergic toxidrome
Cholinergic toxicity occurs when too much acetylcholine is present in the receptor synapse leading to excessive parasympathetic effects.
Cholinergic Toxidrome symptoms (mneumonic)
SLUDGE DUMBELS
S - salivation/spit
L - lacrimation/ ++ tears in eyes and nasal drips
U - urination
D - defecation/diarrhea
G - GI upset
E - emesis/vomit
M - from DUMBELS (myosis - pin point pupils)
B - from DUMBELS (bradycardia - also brings BP down)
Cholinergic drug
Any drug that inhibits, enhances, or mimics the action of NT ACh
Oral or rectal application of medication (i.e. application of enteral medications) is the preferred route for what kinds of situatinos?
stable/chronic conditions or acute non-life threatening conditions
Advantages of Enteral Medications
- Safest and most common
- no need for sterile environment, supplies or training
- slow absorption
Disadvantages of Enteral Medication
- variable rates of absorption
- irritation of mucous linings of stomach and intestine
- patient status/compliance
- most have to pass through liver first (First Pass Metabolism)
Advntages of parenteral administration route (IM, IV, SQ)
rapidly available for immediate circulation to cause desired result
disadvantages of parenteral administration (IM, IV, SQ)
- specialized training and equipment required for administration
- delay in administering (takes time to set up)
- greater chance of detrimental outcome if administration is done incorrectly
Inhalation route of entry: Advantages and Disadvantages
Advantages:
- activates rapidly
- easy to administer
- convenient and easily accessible
- targets receptors in the lungs
Disadvantages:
- environmental limitation
- contamination
In the absence of an IV loading dose, how many half lives must past in order to achieve a steady state of medication in the bloodstream?
5
Where are dopamine receptors and what is their effect when stimulated?
Location: various tissues and organs
Function: causes dilation of renal mesenteric, coronary and cerebral arteries
Taking adrenergic medication would cause what symptoms?
- increased HR, BP
- decreased gastric motility
- increased alertness
- restlessness, irritability, anxiety, pallor
Adverse reactions to adrenergic blockers include:
- drowsiness, fatigue
- bradycardia
- hypotension
- orthostatic hypotension
- diarrhea
What are clinical uses for cholinergic drugs (to increase ACh in synapse)? There are 4.
- Glaucoma - reduce intraocular pressure
- myasthenia gravis - disease caused by lack of ACh at the synapse
- relief of urinary retention
- increase GI motility
