SNS drugs Flashcards
Where are beta-1 receptors located?
- JG Cells
- SA node
- AV node
- myocardium
Which drugs act as agonists of beta-1 receptors of the SNS?
- Dobutamine
What are the effects of dobutamine binding to beta-1 receptors in the heart?
Binding leads to increased:
- heart rate
- contractility (increase SV & CO) increase CO
- conduction
When is dobutamine use indicated? When to use it?
- On acute heart failure
- And Renal failure
Where are beta-2 receptors located?
- Respiratory tract
- Uterus
- Vascular smooth muscle
- Liver
Which drugs act as agonists of beta-2 receptors of the SNS?
- Salbutamol
- Adrenaline
What is the common effect of beta-2 receptors?
-Vasodilation- increase blood flow
What is the effect of salbutamol upon binding to beta-2?
Bronchodilation- reverse
bronchoconstriction
in asthma and COPD
Name the uses of salbutamol (its indications)
- Relax VSM in lung (when bound to Beta-2 in the resp tract)
- glucose release (on beta-2 in the liver)
- prevent premature uterine contraction (on beta-2 in the uterus)
What are the adverse effects of salbutamol?
- tachycardia
- palpitations
- tremor
- hyperglycemia
Adrenalin binds all beta and alpha receptors. Used in anaphylactic shock. What are the effects of it binding Beta-2?
- Bronchodilation
Which drugs act as beta blockers?
- Propranolol (beta-1 cardiac selective blocker)
- Atenolol/ bisoprolol ( beta-1 selective; binds B1-B2 and a1 cardiovascular blockers)
- carvedilol ( non-selective. blocks both beta-1; beta-2; B3; B4))
What are the indications of using bisoprolol and carvedilol?
- Heart failure
- Angina pectoris
What are the indications of using atenolol and bisoprolol?
- hypertension
- Post MI
- Angina pectoris
- arrhythmia
What are the Cardiovascular Adverse Events of using Beta blockers?
- bradycardia
- AV block
- heart failure
- PVD (peripheral vascular disease)
- having to limit exercise
What are the metabolic Adverse Events of using Beta blockers?
- New onset or worsens diabetes
- Blocks sympathetic NS
- hypoglycaemia
NOTE:
Hypoglycaemia can be excercebated by
- Low insulin
* timing of meals (skiping or delaying meals)
* exercising without adjusting carbohydrate intake
* low carbohydrates
When are beta blockers contraindicated?
Asthma & COPD
Which drugs act as agonist of alpha-1 receptors of the SNS?
- Adrenaline (binds beta-1, beta-2, and alpha-1)- To use together with a local anaesthetic for longer duration of the anaesthetic
- phenylephrine
- ephedrine (or amphetamine)
List the indication of phenylephrine? Where is it used, and when is it suitable to use?
BINDS ALPHA-1 in
- upper respiratory tract &
Vascular smooth
MOA- Is a vasoconstrictor
USES:
treat allergies
treat common colds
topical and oral use
List ephedrine adverse effects
- rebound congestion
- increased BP
(SIMILAR TO EPHEDRINE)
Which drugs act as antagonists of alpha-1? (blockers)
-Doxazosin
What’s the MOA of Doxazosin?
Binds and Blocks α 1 post synaptic receptors.
Hamper SNS activity of vasoconstriction. Decreases vascular resistance.
What are the uses of doxazosin?
- hypertension
- Benign Prostatic hyperplasia (BPH)
- improve urine flow from bladder
- not mono therapy
- safety in hypertension? yes!, reduce BP through vasodilation
- 3rd line add on
What are the adverse outcomes of using doxazosin?
- first dose hypotension
- orthostatic hypotension
