Autonomic drugs Flashcards
3 functions of the nervous system
- recognize
- process
- react
the nervous system breaks down into…
- peripheral nervous system
- central nervous system
the peripheral nervous system breaks down into…
- motor neurons
- sensory neurons
what does the motor neurons system break down into
- somatic nervous system
- autonomic nervous system
what does the autonomic nervous system break down into
- sympathetic division
- parasympathetic division
what does the sympathetic nervous system break down into
- adrenergic receptors (further breaks down into alpha and beta)
what does the parasympathetic division break down into
- cholinergic receptors
what does electrical transmission consist of
- ions
what does chemical transmission consist of
- neurotransmitter
which neurons receive and which ones generate impulses
- presynaptic generates
- postsynaptic receives
what is a synapse and what is a synaptic cleft
- synapse is a structure at the end of a nerve
- synaptic cleft is space to bridge between neurons
what are neurotransmitters
- chemicals that bridge the synaptic cleft
what do presynaptic neurons do
- release impulse
what do postsynaptic neurons do
- regenerate impulse
how do drugs work
- by blocking or enhancing activity
what are the number 1 neurotransmitters of the autonomic nervous system
- acetylcholine and norepinephrine
what are the 2 alpha receptors and what do they do
- alpha 1: located on smooth muscles in the blood vessels, constricts blood vessels, also dilates pupils
- alpha 2: inhibits release of norepinephrine, lowers blood pressure by affecting the heart
what are the 2 beta receptors and what do they do
- beta 1: located in the heart and kidneys, increased heart rate and force of contraction, release of renin
- beta 2: all organs but heart; primarily lungs, uterus, skeletal muscles. inhibition of smooth muscles -> relaxation, bronchodilation
what are the 2 acetylcholine receptors
- nicotinic receptors
2. muscarinic receptors
what do nicotinic receptors do
- located in ganglia and skeletal muscles
- stimulation of smooth muscles and gland secretions
what are agonists
- bind to receptors
- produce maximal response
what are antagonists
- bind to receptors
- block receptor or produce sub maximal response
- opposite of agonists
what are autonomic drugs
- classified by which receptor they stimulate or block
- sympathomimetics (adrenergic agonists) stimulate the sympathetic nervous system and the fight or flight response
- parasympathomimetrics (cholinergic agonists) stimulate the PNS and rest and relaxation response
what are adrenergic blockers
- inhibit SNS
- opposite action of sympathomimetics
what are anticholinergic (cholinergic) blockers
- inhibit PNS
- opposite action of parasympathomimetics
what are sympathomimetics
- adrenergic agonists
- stimulate SNS
- produce fight or flight response
- primarily used for effects on heart, bronchial tree and nasal passages
- stimulate alpha and/or beta receptors
- selective (stimulate only one type of adrenergic receptor)
what receptors do alpha 1 stimulate (selective sympathomimetics)
- nasal mucous membranes
- decrease secretions
- nasal and ocular decongestants
- phenylephrine (neo-synephrine)
what receptors do beta 1 stimulate (selective sympathomimetics)
- within heart
- increase heart rate and force of contraction
- ex dobutamine
what receptors do beta 2 stimulate (selective sympathomimetics)
- within airways
- relax smooth muscles -> bronchodilation -> treatment of asthma
- ex salbutamol
what do lower doses of epinephrine cause
- an increase in systolic pressure due to alpha stimulation and beta 1 stimulation (direct stimulation of the heart muscle)
- added to lidocaine injections to: cause vasodilation -> decrease bleeding, makes lidocaine last longer
- note that levonordefrin is also used as a vasoconstrictor in dental local anaesthetics bit is 1/2 as potent as epi
what are non selective sympathomimetics
- mimic or modify the actions of endogenous catecholamines (ex dopamine) of the sympathetic nervous system
- alpha 1 and beta 2: nasal mucous membrane and heart; decongestant; pseudoephedrine
- beta 1 and beta 2: heart and airways, increase force, rate and speed of conduction or for asthma; isoproterenol
- more autonomic side effects
what is ma huang/ephedra
- sympathomimetic
- Chinese herb
- similar actions as ephedrine and pseudoephedrine
- stimulates SNS -> decongestant, bronchodilator, energy enhancer, weight loss
- side effects: increased heart rate and blood pressure
alpha 1 receptor agonists cause what
- smooth muscle contraction
- leads to vasoconstriction, dilation of pupils, contraction of the bladder muscle
what do alpha 2 receptor agonists cause
- treatment of hypertension to lower blood pressure
- drugs will also inhibit the release of norepinephrine resulting in lower levels of norepinephrine
what do beta 1 receptor agonists do
- increase the rate and force of heart contractions (cardiac stimulation) in patients with hypotension and shock
- given intravenously
what do beta 2 receptor agonists do
- cause relaxation or dilation of smooth muscles in the lungs (bronchodilation) in patients with asthma
- given orally or inhaled
- best to select beta 2 drug such as salbutamol or terbutaline to keep adverse side effects to a minimum
what are some adverse effects of non selective sympathomimetics
- xerostomia (dry mouth), nausea, vomiting, headache, dizziness, and palpitations
- increase in blood pressure, tachycardia, fibrillations
- non selective beta antagonists may cause hyperglycaemia
what are some drug interactions of nun selective sympathomimetics
- tricyclic antidepressants decrease EPI effects
- non selective beta-blockers - limit EPI to 0.04 mg (2 cartridges 1:100,000)
- cocaine + epi -> large increase in blood pressure
what are adrenergic blockers
- inhibit sympathetic nervous system
- produce rest and relaxation response
- primarily used for hypertension
- also used for urinary retention, headache (migraine prevention) and glaucoma (increased intraocular pressure)
- most widely prescribed
what are alpha adrenergic receptor antagonists (blockers) - both 1 and 2
- alpha 1 blockers: within blood vessels; relax vascular smooth muscle -> decrease blood pressure; treatment of hypertension, urinary retention and prostate enlargement; doxazosin, terazosin and prazosin
- alpha 2 blockers: yohimbine (yocon) blocks alpha 2 receptors and is used in the treatment of impotency in men
what do adrenergic blockers treat
- hypertension
- angina
- heart arythmias
- panic attacks
- prevention of migraines
- glaucoma
what are adverse effects of adrenergic alpha blockers
- postural hypotension and bradycardia with initial doses
- taking the drug with food may reduce the incidence of dizziness
- food may delay absorption but does not affect the extent of absorption
- watch change of positions
what are adverse effects of adrenergic beta blockers
- can cause heart failure or heart block
- caution should be used in diabetes -> increase insulin action -> hypoglycemia
- non selective beta-2-blockers -> bronchoconstriction -> contraindicated in asthmatics
what drug interactions can exist between adrenergic blockers
- alpha 1 blockers + antihypertensive drugs and diuretics
- phenothiazines + beta-blockers
what are parasympathomimetics
- induce rest and relaxation response
- stimulate PNS
- few therapeutic uses because of numerous side effects (heart, respiratory)
- include organic phosphate insecticides/pesticides and toxic nerve gasses: tabun, sarin and soman
- used to slow the heart + increase smooth muscle tone of the GI and urinary tract (post-op or post-partum)
what are some other uses for parasympathomimetics
- for effects on acetylcholine receptors in the skeletal muscles
- myasthenia gratis has destruction of nicotinic receptors in skeletal muscle (what nanny has)
- neostigmine -> stimulate skeletal muscle contraction to reverse weakness
- prototype drug: bethanechol used post-op to increase urination
what is bethanechol
- direct acting parasympathomimetic
- interacts with ACh receptors -> PNS stimulation effects
- stimulate smooth muscle contraction in digestive and urinary tracts (post op)
what are adverse effects of bethanechol
- increased salivation
- sweating
- abdominal cramping
- hypotension
- not for asthma patients or have obstructions
what are natural plant alkaloids
- cholinergic agents including muscarine, nicotine and pilocarpine
- pilocarpine, which is obtained from a plant shrub, is used to treat xerostomia
- nicotine is obtained from plants and in cigarettes and other tobacco products. contained in chewing gum and transdermal patches for smoking cessation
what are adverse effects of pilocarpine
- flushing
- sweating
- urinary urgency
what are anticholinergics
- inhibit PNS
- induce fight or flight
- = muscarinic blockers
- dilation of pupil, increase heart rate, dry secretions, dilation of bronchi
- many side effects, like tachycardia, urinary retention
- replaced with safer and more effective drugs
what are some examples of anticholinergics
- scopolamine: sedation and motion sickness
- benztropine: Parkinson’s disease
- ipratropium bromide: asthma and/or bronchitis
- tolterodine (detrol): urinary incontinence
what is atropine
- natural product
- found in deadly nightshade plant
- block ACh receptors -> fight or flight response. increased heart rate, bronchodilation, decreased GI motility, mydriasis, decreased gland secretions
- treat hyper motility disorders (treats GI and bladder spasms)
- suppress secretions during surgery
- increase heart rate when bradycardia
- dilate eye during exam, bronchodilation in asthma
what are some other uses of atropine
- to prevent motion sickness
- treat excessive muscle movement especially of the face and neck (acute dystonia) caused by antipsychotic medications
- to counteract organophosphate poisoning
what are some adverse effects of atropine
- xerostomia, urinary retention, blurred vision, constipation, and tachycardia
- contraindicated in glaucoma, BPH, tachycardia
what are some drug interactions for atropine
- additive anticholinergic side effects
- drugs that also have anticholinergic effects, like tricycle antidepressants and antihistamines such as diphenhydramine (Benadryl)
most common use of alpha 1 receptor agonist drugs
- nasal decongestant and hypotension
most common use of alpha 2 receptor agonist drugs
- treatment of hypertension
most common use of beta 2 receptor agonist drugs
- treatment of asthma
primary use fo beta blockers
- treatment of hypertension
