Alkaloid, Tertiary Amine.
Antagonist (blocker) of ACh at Muscarinic Receptors - found in the heart.
USED IN LOW BP SECONDARY TO BRADYCARDIA
3mg IV will totally block the vagus nerve's action on the heart.
Via the vagus nerve, the parasympathetic nervous system stimulates neurons that release the neurotransmitter acetylcholine (ACh) at synapses with cardiac muscle cells. Acetylcholine then binds to M2 muscarinic receptors, causing the decrease in heart rate that is referred to as reflex bradycardia.
Over 90% of the drug and its metabolites are excreted in the urine within 24 h
Bezold-Jarisch reflex can cause bradycardia.
Increased BP only IF hypotension due to brady.
Crosses BBB so can cause delirium & confusion
Reduces SLUDGE (salivation, lacrimation, urination, diaphoresis, gastrointestinal motility, emesis)
IV 100-600mcg is used for bradycardia typically.
Use in PEA/Asystole remains controversial as no evidence supports the use.
Metabolised in the liver to Tropine & Tropic Acid
Dr. David Lyness@Gas_Craic
Sulphate in a lot of the vials cause histamine release &
can cause allergic reactions.
Adverse reactions apart from SLUDGE - can be VF, Supraventricular Tachycardias, Ventricular Tachycardias, Hallucinations & Excitation (Elderly mostly)
Slows down the parasympathetic nervous system - counters the 'rest and digest'
Naturally found in the Belladonna plant!
(Can also useful in treating second-degree heart block Mobitz Type 1 (Wenckebach block), and also third-degree heart block with a high Purkinje or AV-nodal escape rhythm.)