Autonomic Pharmacology part 1 Flashcards
Sympathetic fibers have what postganglionic receptors
Adrenergic (alpha and beta) with Norepinephrine as the neurotransmitter
- Parasympathetic –> Muscarinic receptors
In what 5 ways might drugs modify the ANS activity?
Any of the events associated with neurotransmitters:
- Synthesis
- Storage
- Release
- Receptor interaction
- Disposition (termination of neurotransmitter activity at synapse = enzyme degradation or reuptake)
T or F, Both divisions of the ANS can be affected by the 4 groups of drugs designed for the ANS
True
4 groups of drugs that alter the ANS
- Parasympathetic (PANS) stimulatory
- Parasympathetic (PANS) inhibitory (blocking)
- Sympathetic (SANS) stimulatory
- Sympathetic (SANS) inhibitory (blocking)
How are the drugs affecting the ANS named?
cholinergic - drug that acts at the location where ACETYLCHOLINE is released
Adrenergic - drug that acts at the location where NOREPINEPHRINE is released
parasympatho- = drug that acts where PANS acts sympatho- = drug that acts where SANS acts
When do you name a drug -“mimetic”
When a drug that acts at the location where a division of the ANS acts and produces the same effect as the neurotransmitter
- ** Also known as an agonist drug
A drug that acts at the location where a division of the ANS acts and blocks the action of the neurotransmitter is named?
has the suffix -lytic or - blocker
- Also known as antagonists = no drug effect. they just block receptor site like a plug
Parasympathetic (PANS) drugs
Stimulatory
- cholinergics
- parasympathomimetics
Inhibitory
- anticholinergics
- parasympatholytics
- cholinergic blockers
Sympathetic (SANS) drugs
Stimulatory
- adrenergics
- sympathomimetics
Inhibitory
- adrenergic blockers
- sympathetic blockers
- sympatholytics
2 types of cholinergic agonists
- Direct acting
- act at the acetylcholine receptor
- Indirect acting
- causes the release of acetylcholine
- Cholinesterase inhibitors = cause accumulation of ACH = stimulating PANS
5 characteristics about Direct Acting Cholinergic Drugs
- Act like acetylcholine on receptors
- Agonists
- LONGER duration of action
- MORE SELECTIVE in the effects produced
- SIMULATE the PANS
To an effective mediator, ACh must fit a receptor how?
Physically and Chemically
How do ACh receptors play a role in differences in the response of the receptor to drugs
- There are differences among receptors that have ACh as their neurotransmitter
- Subtypes of ACh receptors are located in different synapses
- Other factors:
- Amount of ACh released
- Size of synaptic cleft
- Tissue penetration of a drug
Pharmacologic Effects of Cholinergic Drugs
- Cardiovascular (bradycardia, decreased BP and cardiac output)
- Eye (produce Miosis, Decreases intraocular pressure
- GI (Excites smooth muscle of gut; Increase in activity, motility and secretion)
T or F, Cholinergic drugs decrease the activity of the GI
False, increase and excite smooth muscle
Primary indications for Direct Acting Cholinergic drugs
- *Glaucoma
- *Myasthenia graves (autoimmune disease)
- GI disorders (increase GI motility)
- Reverse urinary retention after surgery
5 examples of Direct Acting Cholinergic Agonists
- acetylcholine (Miochol) - eye surgery
- bethanechol (Urecholine) - urinary retention
- carbachol (Miostat) - glaucoma
- *cevimeline (Evoxac) - Sjogren’s syndrome
- *pilocarpine (Salagen) - glaucoma, Sjogren’s syndrome
Role of pilocarpine in treatment of glaucoma
By causing pupil constriction, allows for drainage of fluid from the eye through the canal of Schlem
- Glaucoma is increased intraocular pressure due to fluid accumulation
Other than opthalmically, how is pilocarpine used in dentistry?
To stimulate salivary secretions in patients with xerostomia
- for patients with Sjogren’s syndrome or salivary gland damage from head and neck irradiation
What is another drug similar to pilocarpine (in the same class) and is used for salivary stimulation in patients with Sjogren’s syndrome?
cevimeline (Evoxac)
What class of drugs are also known as “cholinesterase inhibitors”?
Indirect-Acting Cholinergic Drugs
What do cholinesterase inhibitor drugs do?
Stop the breakdown of acetylcholine, which allows for the concentration of acetylcholine to build up = acetylcholine remains active and stimulates the PANS
-**Produce PANS stimulation
T or F, cholinesterase inhibitors produce PANS inhibition
False, PANS stimulation
Primary indications for Indirect-Acting Cholinergic Agonists
- Myasthenia Gravis
- Glaucoma
- Postoperative urinary retention
- Paralytic ileus (malfunction of nerves in intestine without physical blockage)
- Antidotes to agents that produce non depolarizing neuromuscular blockade (poisons)
Indirect-Acting Cholinergic Drugs are divided into groups based on what?
degree of reversibility with which they are bound to the enzyme
- Reversible (also includes centrally-acting drugs)
- Irreversible
Reversible cholinesterase inhibitors are used to treat what?
(REMEMBER: increase ACH)
- Used to treat myasthenia graves and glaucoma
3 drugs in the Reversible cholinesterase inhibitors class
- edrophonium (Enlon)
- physostigmine
- pyridostigmine (Mestinon)
Which Reversible cholinesterase inhibitor reverses toxic life-threatening delirium caused by overdoses of anticholinergic drugs?
physostigmine
Examples of Centrally acting acetylcholinesterase inhibitors
- **donepezil (Aricept)
- rivastigmine (Exelon)
- galantamine (Razadyne)
- *Dementia with Alzheimer’s disease
- Investigational for mild to moderate dementia with parkinson’s disease
Describe the Irreversible Acetylcholinesterase Inhibitors
- malathion, parathion = poisons
- used as agricultural insecticides (organophosphates)
- sarin, Soman, tabun = nerve gases, chemical warfare
***Raise ACH = too much
If someone is poisoned (overdose) with insecticides or organophosphates, use what antidotes:
- *pralidoxime (2-PAM, protopam)
- Regenerates the irreversibly bound ACH receptor sites that are bound by the inhibitors
- *atropine (antimuscarinic)
- Competitively blocks muscarinic effects of excess ACH
Side effects of Cholinergic drugs
SLUD
- Salivation
- Lacrimation
- Urination
- Defecation
3 categories of Cholinergic Antagonists (Anticholinergics = Parasympatholytics)
Anticholinergics = Antimuscarinics
Neuromuscular blocking agents
Ganglionic blocking agents
Describe the actions of Anticholinergic drugs
- Prevent the action of acetylcholine at the postganglionic PANS nerve endings
- **Block the rector site for acetylcholine
- Do not prevent release of ACH
- ACH cannot act on receptors in smooth muscle, glands or the heart
Anticholinergic drugs are also called?
antimuscarinic drugs (block muscarinic receptors but not nicotinic receptors)
Pharmacologic effects of Anticholinergic Drugs
- Eyes = mydriasis
- Skin = decrease sweating
- GI = decrease salivation, decreased gut motility
- Urinary tract = urine retention
- Respiratory = bronchodilation
- CNS = sedation; decreased concentration/memory
- CVS = Large therapeutic doses = vagal blockade, resulting in tachycardia
Therapeutic doses of scopolamine produces what?
Atropine in high doses produces what?
Scopolamine: sedation, motion sickness
Atropine: stimulation: delirium, hallucinations, convulsions, coma
Anticholinergic drugs are used in dentistry for what?
To decrease salivation and create dry field for bonded restorations and impressions (atropine)
T or F, Anticholinergic drugs produce a bronchodilation effect to facilitate breathing but increases gut motility causing diarrhea
False, It does produce bronchodilation
It does NOT increase gut motility. It DECREASES gut motility and can cause constipation as side effect
Explain the pharmacologic effects of anticholinergic drugs on the Eye
- Mydriasis (dilated pupils)
- cycloplegia (paralysis of accommodation so that the lens is focused for distance vision and near vision is blurred.)
- Drops used for ophthalmologic examination
Large or Low therapeutic doses cause a vagal blockade in CVS resulting in tachycardia?
Large
- Used to prevent cardiac slowing during general anesthesia
Clinical uses of Anticholinergic Drugs
- Preoperative medications
- GI disorders that produce excess secretions and increased gut motility
- Eye examination
- Parkinson’s disease
- GU disorders
- Motion Sickness
- Dentistry - to maintain a dry field
Why might preoperative medication of anticholinergic drug be useful?
- Stop salivation and bronchial mucous (normally stimulated by general anesthesia)
- Block slowing of heart rate caused by general anesthesia
Describe the uses of anticholinergic in GI disorders
- Stops excess acid secretion (peptic ulcer disease)
2. Stops diarrhea and cramping - antispasmodic for IBS`
Use of anticholinergic drugs in Eye examinations
- Causes pupil dilation to allow for examination of retina
- Relaxes lens for determining prescription for eyeglasses
Which kind of anticholinergic patch is used behind the ear for motion sickness
Scopolamine
CNS depressant
What anticholinergic substance is used in dentistry to maintain a dry field
Atropine
T or F, Atropine = cholinergic = salivation
Pilocarpine = anticholinergic = dries saliva
False, Atropine = anticholinergic = dries saliva
Pilocarpine = cholinergic = salivation
Popular Anticholinergic Medications
- atropine (dentistry = stop salivation)
- scopolamine (Patch used for motion sickness)
- ipratropium (Atrovent)
What is the drug of choice for emphysema
ipratropium (Atrovent)
Stops bronchial secretions
Contraindications to Anticholinergic drugs
- Glaucoma (intraocular pressure is too high)
- Prostatic hypertrophy (cause urinary retention)
- Intestinal or urinary obstruction or retention
- Cardiovascular disease (overburdened heart; tachycardia)
Mnemonic for atropine toxicity
- Dry as a bone (lack of sweating)
- Red as a beet (flushed skin)
- Blind as a bat (blurred vision; mydriasis and cycloplegia)
- Mad as a hatter (delirium, hallucinations)
Treatment of atropine overdose
physostigmine or pralidoxime: acetylcholinesterase inhibitor
