Pharmacology and drug therapy of shock

1. Dr.Ajay Kumar
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Drug Therapy
of Shock
Dr. Ajay Kumar
M. Pharm., Ph.D
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2. MANAGEMENT OF SHOCK
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• Shock is also called circulatory failure.
• O2 perfusion fails to meet the metabolic demands.
• Results in regional hypoxia & lactic acidosis
• Eventually leads to end organ damage & failure.
Classification
• Hypovolaemic shock
• Cardiogenic shock
• Septic shock
• Anaphylactic shock

3. HYPOVOLAEMIC SHOCK
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• Results from major reduction in blood volume.
• Loss of plasma due to burns.
• Loss of fluid & electrolytes– vomiting &
diarrhea.
Cardiogenic shock
• Results due to severe pump failure.
• E.g MI, cardiomyopathy,
• Arrhythmias
• Valvular dysfunction

4. SEPTIC SHOCK
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• Occurs secondary to Gram negative bacteraemia.
• Risk factors are extremes of age, DM,
immunosuppression, invasive procedure.
• Vasodilatation occurs secondary to endotoxins.
• Also called warm shock.
Anaphylactic shock
• Severe immediate hypersensitivity reaction.
• Excessivevasodilatation, ↑capillary permeability, exudation,
angioneurotic edema, bronchoconstriction.

5. NEUROGENIC SHOCK
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• Caused by traumatic spinal cord injury ,
• Spinal/epidural anesthesia adverse effect.
• Resultsin lossof sympathetic tone→
• Reflex vagal parasympathetic stimulation →
• Vasodilatation, hypotension, bradycardia & syncope.
• CVP is typically reduced in hypovolemic
& anaphylactic shock.
• CVP elevated in cardiogenic shock, unpredictable in
neurogenic / septic shock.

6. MANAGEMENT OF SHOCK
HYPOVOLAEMIC SHOCK
• Treated with immediate infusion of blood substitutes
• In severe dehydration volume replacement with- raid
infusion of isotonic saline/RL.
• Plasma expanders (colloids) not useful.
• Dopamine to maintain adequate ventricular
performance.
• Phenoxybenzamine- counteract vasoconstriction,
shifts blood from pulmonary to systemic circuit &
extravascular to vascularcompartment,↑CO 6

7. • Dopamine infusion (2-3mcg/kg/min)- stimlates D1
R in kidney & β1 R in heart.
• ↑ HR,contractility, & GFR.
• Phenylephrine is alt for pt at risk of arrhythmias.
• O2 should be supplemented
Cardiogenic shock
• Requires small amounts of fluid replacement.
• Dobutamine: 2.5μg/kg/min I.V infusion.
• ↑contractility, ↓afterload
• Dopamine 2-3μg/kg/min I.V infusion.
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8. SEPTIC SHOCK
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• Norepinephrine: reserved for patients with refractory
hypotension 2-4μg/kg/min I.V infusion.
• Treat the infection-
meropenem(I.V)/ticarcillin+clavulanic acid.
• Requires large volumes of fluid replacement due to
capillary leak.
• Drotrecogin alpha: 24μg/kg/hr for 96hrs improves
mortality in severe septic shock with organ failure.
• Vasopressin: causes peripheral vasoconstriction (V1).
• ReducesNOsynthesis,↑the effect ofcatecholamines on
vasculature. Stimulate cortisol production

9. • ↑BPevenif there isresistanceto adrenaline.
• Corticosteroids: hydrocortisone (50mg QID) with
fludrocortisone (50mcg OD) X7 days.
• Supress formation of NO & PG.
• Shortens duration of use of vaspressors, ↓mortality.
• Prevents adrenal insufficiency.
• Positive ionotropes useful in some patients.
• Other measures by maintaining
 Pulmonary capillary wedge pressure: 12-16mmHg, CVP:
8-12cm H2O
 Proper urine output: furosemide may be used.
 Blood glucose levels.
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10. ANAPHYLACTIC
SHOCK
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• Adrenaline 0.5 mg (0.5 ml of 1 in 1000 solution) i.m.; repeat
every 5-10 min in case patient does not improve or
improvement is transient.
• Causes bronchodilatation &↑BP.
• H1 antagonists & glucocorticoids are used as adjuvants
Neurogenic shock
• Rx similar to hypovolemic shock.
• Norepinephrine/phenylephrine to maintain BP.

11. THANK YOU
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