Pharmacology of the ANS Flashcards
Describe the Parasympathetic Nervous System Stimulation. Describe Reversible and Irreversible Agents.
ACh-esterase breaks down ACh,
Stimulation is due to ACh-esterase inhbitors
Stimulated by Acetylcholine-which has a short half life
ACh-esterase inhibitors
Reversible: (N-a-R-P)
1. Neostigmine (Injection Only) and Pyridostigmine(Oral)
2. Alzheimer’s: Increase ACh levels usuing Rivastigmine
3. Mysthenia Gravis: treat with Neostigmine and Pyridostigmine
Irreversible:
Include: Organosphosphates, Pesticides, Malathion, salivation, Bradycardia, Diarrhoea, Sweating, Bronchocontriction, Mucous production
Describe the PNS blockers and the agents for this action
MOA- Block action of ACh on muscarinic receptors
Agents include (GHA)
1. Glycopyrrolate (only parenteral, used prior to surgery- can cross BBB)
2. Hyoscine
3. Atropine
Uses
GIT- Irritable bowel syndrome, Diarrhoea, use Hyoscine which has less A/E than Atropine
Surgical
-prevents surgery-induced bradycardia
-Prevents salivation(which could aspirate and cause pneumonia)
Respiratory
Asthma and COPD
-Ipratropium Bromide- Use with Salbutamol in ASTHMA or alone in COPD- metered dose inhaler
-Tiotropium bromide-has longer half-life than Ipratropium, used in COPD
**Glycopyrronium Bromide (Glycopyrrolate)-metred dose inhaler or parenteral before surgery
Describe the PNS
Controls the Heart, Respiratory Tract, Urinary Tract
Urinary Tract
Sphincter-relax
Bladder-relax
Penile-Erection
Respiratory tract
Bronchoconstriction ‘
Mocus production
Heart
Decreases Heart Rate
PNS blockers
Describe Anticholinergic Side Effects and contraindications of ACh blockers
Anticholinergic side effects
-dry mouth
tachycardia
constipation
bluured visison
urine retention
reducution in sweating
CONTRAINDICATIONS
Tricyclic Antidepressants
H1 Receptor Antagonists
Functions of Sympathetic Nervous System
Activated when I’m jogging
Increases Cardia Output, causes peripheral vasocconstriciton and increases blood pressure. decreases blood flow to mesentary and skin. increases blood flow to brain, heart and skeletal muscle.
SYMPATHETIC NERVOUS SYSTEM
Describe the activity of beta-1 and beta-2 receptors.
Beta-1 receptors
1.Juxtaglomerular cells: when stimulated, releases renin, activating the RAAS
2.Increased SA node activity
3.Increased conduction at the AV node
4.Myocardium
5.Beta-2 receptors
1. Cause dilation
2. Lower resporatory tract
3. Pregnant Uterus
4. Vascular smooth muscle
5. Liver
SYMPATHETIC NERVOUS SYSTEM
Describe the direct and indirect agonists of the SNS
Alpha-1 Agonists
Direct Agonist
Phenylephrine which is an Alpha-1 agonist
Alpha-1 receptor:
1. Upper respiratory
2. Vascular smooth muscle
3. Vasocontrisctor
4. Treats allergies
5. Treats common colds
6. Topical and Oral
Adverse Effects: Increased blood pressure(oral),and rebound congestion of used for more than 3-5 days (topical)
Indirect Agonist
3 agents namely, Ephedrine, Amphetamine and Cocaine
Ephedrine
1. weak release
2. acts on alpha-1
3. Only Oral–“Oral” side effects
4. causes release of noradrenaline in presynaptic terminals
Amphetamine
1. Potent release
2. Release of Noradrenaline, Dopamine and Serotonin
Cocaine
- Reutake Inhibitor
- Afftects NA, Dopamine and Serotonin
- Acts on brain, nasal mucosa, and heart
Describe the Agents, Indications, and Adverse Effects of *Short Acting Beta-2 Agonists (SABA)
Agents
1.Salbutamol (Oral, IV or MDI)
2.Fenotorol (MDI)
Indications
1. Reverse Bronchoconstriction in Asthma and COPD (cause bronchodilation)
2. Glucose release
3. Prevent premature Uterine Contraction in Pregnancy
4. Relax vascular smooth muscle in the lung
Adverse Effects
(through beta-1 receptors)
1. Skeletal Muscle Tremor
2. Hyperglycaemia
3. CVS-related:Tachycardia and Palpitations
Describe the Adverse Effects, Uses and Agents of Long Acting beta-2 Agonists (LABA)
AGENTS
1. Salmeterol (MDI)
2. Formoterol (MDI)
Same Indications as SABA
Same Adverse Effects as SABA
Describe what happens in Anaphylactic Shock and how we treat it.
Anaphylactic Shock
1. Alpha-1: Decrease in BP (intense vasodilation)
2. Beta-1: Drop in cardiac output
3. Beta-2: Bronchoconstricition
This is treated with Adrenaline
Adrenaline with reverse these effects in each receptor respectively.
- Alpha-1: Vasoconstiction
- Beta-1: Increase cardia output
- Beta-2: Bronchodilation
Describe Sympathetic Nervous System beta blockers
Describe the AGENTS
-
Propranolol
Non-selective: beta-1 and beta-2 receptors -
Atenolol and bisoprolol
Beta-1 receptors (cardio selective) - Carvedilol:
Beta-1, beta-2 and alpha-1 receptors (very safe) - CNS aderse effects
Vivid dreams, Depression, (This is due to blockage of beta receptors in the brain)