Vasoactive drugs
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Transcript of Vasoactive drugs
Vaso-active drugs
By Dr. Ahmed Galal
PICU specialist
Definition of vasoactive drugs
These are drugs that has effect on heart & circulatory
system
Adrenergic receptors
Β receptors α receptorsβ2 β1 α2 α1
• Sm.ms. Relaxation in bronchioles, blood vs., uterus
• Increase renin• Gluconeogenesis
& glycolysis
• Heart: intropy, chronotropy & improve ejection fraction
• Increase renin
• Inhibits insulin release
• Stim. Glucagon release
• Inhibit noradrenaline relase
• VC of bl.vs. of skin, GIT, kidney, brain
• Sm.ms. Contraction of uterus, ureter, cilliary body
• Gluconeogenesis & glycolysis
Classification of vasoactive drugs
Vasopressor Inotropic Vasodilator
AdrenalineNoradrenaline
Phenyl epherineVasopressin
Ephidrine
DopamineDobutamine
AmrinoneMilrinone
AdrenalineDigoxinCalcium
Na NitroperrusideNitroglycerine
Hydralazine
AdrenalineMechanism of action:
It stimulates α1 & β1 & 2 adrenergic receptors
Vasoconstriction causing hypertension
Inotropic & chronotropic effect
Bronchodilatationantishock
Action: Indications:
Shock (all types)Heart failure
Asthma & croupAnaphylaxis
Nasal obstruction & local haemostasis
AdrenalineDosing
Shock (IV or IO): 0.05 – 1 mic/kg/min.Anaphylaxis or asthma (IM or SC): 0.1 ml/kg of 1/1000 solution
Arrest (IV or IO): 0.1 ml/kg of 1/10,000 solutionArrest (ET): 0.1 ml/kg of 1/1000 solution
Side effectsTachycardia & tachy-arrythmia
Renal impairment & urine retention (in high doses)Rebound bronchospasm
Skin necrosisMesenteric vaso-constiction & ischemia (in high doses)
RFVF
Nor-adrenalineMechanism of action:
It stimulates α1 & weaker on β1 adrenergic receptors
Vasoconstriction causing hypertension
Very weak Inotropic & chronotropic effect
Action: Indications:
Shock (hypotensive& vasoplegic)
Can be used in hypotensive fallot tetralogy patient
with cyanotic spell
Nor-adrenalineDosing
Shock (IV or IO): 0.05 – 2 mic/kg/min.
Side effects
Renal impairment even in low dosesSkin necrosis esp. if extravasated
Mesenteric vaso-constiction & ischemia (in high doses)Tachycardia & tachy-arrythmia to a lesser extent
DopamineMechanism of action:
It stimulates α1, α2, β1& to a lesser extent β2 adrenergic receptorsIt also stimulates dopaminergic receptor (DA1 & DA2)
Low dose: ++ DA1 & DA2Intermediate dose: ++ β
High dose: ++ α1
Action: Systematic action:
Low doses: for mesenteric ischemia
Intermediate dose: cardiac & septic shock
High doses: hypotensive shock
Renal dose become obsolete
DopamineDosing
Low dose: 2 – 5 mic/kg/minIntermediate dose: 5 – 10 mic/kg/min
High dose:10 – 20 mic/kg/min
Side effects
Tachycardia & tachy-arrythmiaSkin necrosis if extravasated
DobutamineMechanism of action:
It stimulates β1 & very mild β2& α1 adrenergic receptors
Inotropic & chronotropic effect
May cause mild vasodilatation
Action: Indications:
Heart failureCold septic shock with normal blood pressure
With noradrenaline to save mesenteric vasculature
Improve the diastolic
dysfunction
DobutamineDosing
5 – 20 mic/kg/min may increase to 30 mic
Side effects
Tachycardia & tachy-arrythmiaSkin necrosis if extravasation
MilrinoneMechanism of action:
It is phosphodiesterase inhibitor so, increase cAMP that lead to increase Ca delivery to myocardium
Inotropic & chronotropic effect
Vasodilatation (pulmonary & systemic)
Action: Indications:
Cardiac failurePulmonary hypertension
Cold septic shock with normal blood pressure
Improve the diastolic
dysfunction& Rt sided failure
Inhalation in pulmonary
hypertension
MilrinoneDosing
0.5 – 0.75mic/kg/min
Side effects
HypotensionTachycardia & tachy-arrythmia
ThrombocytopeniaShould be adjusted in renal imaprement
VasopressineMechanism of action:
It stimulates VR1 causing increase cAMP that lead to increasing Ca delivery to bl. Vs wall
Vasoconstriction causing hypertension
Water retention causing renal impairment
Decrease intestinal motility & gut ischemia
Action: Indications:
Profound hypotensionDI
GI bleeding
ADH analogue
VasopressineDosing
0.0005 – 0.01mic/kg/hr
Side effects
Anuria & renal failureSevere mesenteric ischemia
Hyponatremia
Vasodilator drugsInhibits ACE so, decrease angiotensin 2 (potent VC)
Captopril, ramipril
ACE inhibitors
Competitive inhibition to angio 2 receptors
Losartan Angiotengen 2 receptor antagonist
Block Ca entrance to vascular wall causing relaxation
Nifidipine, amlodipine
Ca channel blockers
NO donor, increase cGMP causing relaxation
Nitroglycerine, nitroperusside
Nitrates
Comprtitive inhibition of α1 receptors
Phentolamine Adrenoreceptor antagonists
Bind to dopaminergic receptors Fenoldapam Dopaminergic receptor agonists
Bind to PG receptor increasing cGMP
alprostadil Prostaglandin
Direct areriolar dilatation Hydralazine
NitroglycerineMechanism of action:
It is NO donor so, stimulation of cGMP causing vascular wall relaxation
Vasodilator mainly veinsDecrease myocardial oxygen
demands (by improving atrial filling pressure by
venodilatation)
Action: Indications:
Heart failureCold septic shock with normal blood pressureHypertensive urgencies
Cautious use in shock
NitroglycerineDosing
0.5 – 5 mic/kg/min upto 20 mic/kg/min in hypertensive emergencies
Side effects
Tachycardia, hypotensionPrespiration
Headache
NitroperossideMechanism of action:
It is NO donor so, stimulation of cGMP causing vascular wall relaxation
Vasodilator mainly arteriolarHypotension
Action: Indications:
Hypertensive urgencies
NitroperossideDosing
0.5 – 1 mic/kg/min
Side effects
Tachycardia, hypotensionHeadache
Thank you