DRUGS ACTING ON THE AUTONOMIC NERVOUS SYSTEM Flashcards
What is peripheral nervous system includes?
Includes the somatic and autonomic nervous systems which control voluntary and involuntary functions respectively.
Which part of spine Sympathetic nervous system arise from ?
Arises from the thoracic and lumbar areas of the spinal cord.
The preganglionic fibers for the parasympathetic nervous system arise from the cranial and sacral nerves.
Autonomic nervous system pharmacology refers to?
Study of drugs that affect the functioning of the autonomic nervous system, which controls many of the involuntary bodily functions, including heart rate, blood pressure, digestion, and respiratory rate. These drugs can either mimic or block the actions of neurotransmitters, such as acetylcholine and norepinephrine, that are released by the autonomic nervous system.
Autonomic drugs can be classified as
Sympathetic or Parasympathetic drugs
The autonomic nervous system is further divided into
Sympathetic nervous system and Parasympathetic nervous system.
Sympathetic nervous system is responsible for
“fight or flight” response in the body. When activated, it increases heart rate, blood pressure, and respiratory rate.
The parasympathetic nervous system is responsible for the “rest and digest” response in the body. When activated, it slows down heart rate, decreases blood pressure,
“rest and digest” response in the body. When activated, it slows down heart rate, decreases blood pressure.
What is the Third division of autonomic nervous system?
Enteric nervous system, which regulates the digestive tract’s motility and secretion.
Autonomic nervous system is essential for
regulating many of the body’s vital functions and maintaining homeostasis.
Which are two important neurotransmitters in the autonomic nervous system?
Acetylcholine and Nor-adrenaline (norepinephrine)
What is Acetylcholine?
Acetylcholine is a neurotransmitter which is released after stimulation of the parasympathetic nervous system to act on effector organs (cells) to elicit their response
What is the function of neurotransmitter?
Provide passage of an impulse across a synapse
what is cholinergic receptor?
A type of receptor that binds to the neurotransmitter acetylcholine. These receptors are found throughout the body, including in the brain, the neuromuscular junction, and other organs.
What are two types of cholinergic receptors?
Nicotinic and Muscarinic.
Nicotinic receptors mediate
muscle contraction
Muscarinic receptors are found in
brain and in smooth muscle
What is the function of Muscarinic receptors?
Regulation of heart rate, smooth muscle contraction, and glandular secretion.
Cholinergic drugs are also called
Parasympathomimetics
How many groups of cholinergic drugs?
2 groups. Direct-acting and Indirect-acting
There are two sub group of direct-acting cholinergic drugs:
Esters of choline and Cholinergic alkaloids
What are Esters of choline drugs?
Methacholine, Carbachol, Betanechol
What are Cholinergic alkaloids drugs?
Pilocarpine, Muscarine, Arecoline, Nicotine
BETANECHOL is contraindicated to?
Bronchial asthma, Hyperthyroidism, Peptic ulcer disease, Coronary insufficiency
What is PILOCARPINE Indication?
Glaucoma
What is PHYSOSTIGMINE Indication?
- Glaucoma
- Atropine over dosage
What is NEOSTIGMINE Indication?
- Myasthenia gravis
- Paralytic Ileus
- Reversal of effect of muscle relaxants, e.g. tubocurarine
- Post operative urine retention
What is effect of ATROPINE in eye?
- Relaxation of constrictor pupillae (mydriasis)
- Relaxation or weakening of ciliary muscle (cycloplegia-loss of the ability
to accommodate)
What is effect of ATROPINE in CNS?
- Lower doses produce sedation
- Higher doses produce excitation, agitation and hallucination
What is effect of ATROPINE in CVS?
- Blocks vagal parasympathetic stimulation (tachycardia)
- Vasoconstriction
What is effect of ATROPINE in Respiratory?
Bronchodilatation and reduction of secretion
What is effect of ATROPINE in GIT?
Relaxes smooth muscle of ureter and bladder wall; voiding is slowed
What is effect of ATROPINE in Sweat Glands?
Suppresses sweating
What are clinical indication for Atropine?
Pre anesthetic medication -to reduce the amount of secretion and to prevent excessive vagal tone due to anesthesia.
As antispasmodic in cases of intestinal, biliary, and renal colic
Heart block
Hyperhidrosis
Organophosphate poisonings
What are side effects of Atropine?
- Dryness of the mouth, tachycardia and blurred vision
- Retention of urine
What are contraindication of Atropine?
Glaucoma and Bladder outlet obstruction.
What is Pharmacokinetics of Atropine
Atropine is absorbed completely from all sites of administration except from the skin wall, where absorption is for limited extent; it has good distribution. About 60% of the drug is excreted
unchanged in urine.
HYOSCINE is also called
SCOPOLAMINE
What is difference between hyoscine and atropine?
This drug has the same effect as atropine except for some differences which includes:-
- It has shorter duration of action
- It is more depressant to the CNS.
Sympathetic nervous system (SNS), which is a part of
the autonomic nervous system (ANS) that regulates various physiological functions, including the “fight or flight” response.
Why hyoscine has certain advantages over atropine?
A. Better for preanesthetic medication because of strong antisecretory and antiemetic action and also brings about amnesia
B. Can be used for short- travel motion sickness
What are the neurotransmitters of sympathetic nervous system?
Norepinephrine from sympathetic nerve endings (Sympathetic effector cells)
Give some example of sympathetic effector cells?
- Smooth muscle cells in the walls of blood vessels
- Cardiac muscle cells in the heart
- Gland cells in the adrenal medulla
epinephrine is also called
adrenaline
norepinephrine is also called
noradrenaline
what are catecholamines?
A group of hormones and neurotransmitters that play important roles in the body’s response to stress, regulation of blood pressure and heart rate, and the activation of the “fight or flight” response.
Name few catecholamines?
epinephrine
norepinephrine
dopamine
Sympathetic nervous system is also called
The adrenergic system (part of autonomic nervous system)
Which is nervous system is responsible for the body’s response to stress and emergency situations?
Autonomic nervous system (adrenergic system)
Release of the catecholamines is primarily mediated from
the adrenal gland and sympathetic nerve endings.
The activation of the adrenergic system (autonomic nervous system ) can lead to
Decreased digestive activity. , increased heart rate, blood pressure, and blood sugar levels, dilation of the pupils, bronchodilation (all are “fight or flight” responses)
Drugs that target the adrenergic system are used in the treatment of various conditions like:
Hypertension, asthma, and certain types of heart disease
What is effect of activation of adrenergic system in skeletal muscle?
Dilatation of skeletal muscle vessels
What is effect of activation of adrenergic system in Blood Vessels and Blood pressure?
Constriction of blood vessels in the skin and mucous membranes
What is effect of activation of adrenergic system in smooth muscles?
a. Bronchi: relaxation.
b. Uterus: relaxation of the pregnant uterus
c. GIT: relaxation of wall muscles and contraction of sphincters
d. Bladder: relaxation of detrusor muscle; contraction of sphincter and trigone muscle
What is agonist?
Neurotransmitters in the brain, agonists are chemicals that mimic the action of natural neurotransmitters by binding to specific receptors and activating them, leading to various effects such as increased or decreased neuronal activity.
In pharmacology, agonists can be used to activate or enhance the activity of a specific receptor to treat various medical conditions.
What is antagonist?
An antagonist refers to a substance that can bind to a specific receptor and block or inhibit its activity, thus preventing the natural ligand or agonist from binding and producing a physiological response.
In pharmacology, antagonists can be used to block or inhibit the activity of a specific receptor to treat various medical conditions, such as high blood pressure
How many adrenergic receptors are in human body?
Alpha 1 and Alpha 2 adrenergic receptors
What is the characteristics of Alpha 1 adrenergic receptors?
Found in many tissues throughout the body, including blood vessels, the heart, and smooth muscles, and their activation can cause vasoconstriction (narrowing of blood vessels), increased heart rate, and smooth muscle contraction.
Is Alpha 1 receptor a neurotransmitters?
Alpha 1 receptors are not neurotransmitters, but rather a type of adrenergic receptor that responds to the neurotransmitter norepinephrine (also known as noradrenaline) and the hormone epinephrine (also known as adrenaline).
Epinephrine is a hormone that is released
by the adrenal medulla
What are the Alpha 1 agonist drugs?
Phenylephrine
Methoxamine
What are the Alpha 2 agonist drugs?
Clonidine
Oxymetazoline
What are the Alpha 1 antagonist drugs?
Prazosin
Phentolamine
Phenoxybenzamine
What are the Alpha 2 antagonist drugs?
Yohimbine
Phentolamine
Phenoxybenzamine
Adrenaline stimulates
all the four receptor subtypes (Alpha 1, Alpha 2, Beta 1 and Beta 2)
Noradrenaline stimulates
Both alpha receptors and beta1 but has very poor affinity for beta2
Why adrenaline is ineffective by oral route?
Adrenaline is rapidly destroyed in the gastrointestinal tract.
Should be given intramuscularly or subcutaneous. Intravenous injection is highly dangerous and is likely to precipitate ventricular fibrillation.
What are the indications of ADRENALINE?
- Acute bronchial asthma
- Anaphylaxis
- Local haemostatic to stop bleeding in epistaxis
- With local anesthesia to prolong the action
- Cardiac arrest
What are the adverse reactions of ADRENALINE?
- Anxiety, restlessness, headache tremor
- Anginal pain
- Cardiac arrhythmias and palpitations
- Sharp rise in blood pressure
- Sever vasoconstriction resulting in gangrene of extremities
- Tearing, conjunctival hyperemia
What are the contra-indication of ADRENALINE?
- Coronary diseases
- Hyperthyroidism
- Hypertension
- Digitalis therapy
- Injection around end arteries
What are indications of NOR ADRENALINE?
Nor adrenalines is used as hypertensive agent in hypotensive states
What are adverse effects of NOR ADRENALINE?
- Anxiety, headache, bradycardia are common side effects
- Severe Hypertension in sensitive individuals
- Extravasation of the drug causes necrosis and sloughing.
Name the catecholamines
ISOPRENALINE DOPAMINE, DOBUTAMINE. NOR ADRENALINE
Name the none-catecholamines
EPHEDRINE
EPHEDRINE should use for
- Bronchial asthma: - usually as a prophylactic for prevention of attacks
- Nasal decongestion
- Mydriasis
- Heart block
- Nocturnal enuresis
Prazosin is a
Alpha adrenergic receptor antagonists (use for hypertension)
High affinity for alpha1 receptor and relatively low affinity for the alpha2 receptor
Prazosin drug is used for
- Essential hypertension
- Raynaud’s syndrome
- BPH (Benign prostatic hyperplasia)
PROPRANOLOL is used for
- Cardiac arrhythmias
- Hypertension
- Prophylaxis against angina
- Myocardial infarction
- Thyrotoxicosis
- Anxiety states (suppression of the physical manifestations of situational anxiety)
- Prophylaxis against migraine attacks
- Glaucoma
PROPRANOLOL is a
non- selective β adrenergic blocker;
What is the effect of PROPRANOLOL in CVS?
- Bradycardia
- Reduces force of contraction
- Reduces blood pressure
What is the effect of PROPRANOLOL in Respiratory system?
Bronchoconstriction
What is the effect of PROPRANOLOL in Metabolic system?
Hypoglycemia
What is the effect of PROPRANOLOL in CNS?
Anti-anxiety action
What is the effect of PROPRANOLOL in eye?
Decrease the rate of Aqueous humor production
What is the effect of PROPRANOLOL in Kidneys?
Decrease renin secretion
What are the adverse effects of PROPRANOLOL ?
- GI disturbances like nausea, vomiting
- Heart failure
- Heart block
- Hypotension and severe bradycardia
- Bronchospasm
What is the effect of PROPRANOLOL to diabetes patient?
Masking of hypoglycemia in diabetic patients
Does PROPRANOLOL produced hallucinations?
Vivid dreams night mare and hallucinations
What are the contra-indication of PROPRANOLOL?
- Bronchial asthma
- Diabetes mellitus
- Heart failure
- Peripheral vascular disease
What are the Noncatecholmines?
Ephedrine, Phenylephrine, Amphetamine
What are the Catecholamines?
Adrenaline
Noradrenaline
Dopamine
Isoprenaline
Dobutamine
Catecholamines have a direct action:
on sympathetic effectors cells through interactions with receptor sites on the cell membrane.
What is the effects of Acetylcholine?
Acetylcholine is a neurotransmitter that plays an important role in the nervous system, including both the central nervous system (CNS) and the peripheral nervous system (PNS).
