Pharmacological Actions Of Adrenaline

Pharmacological Actions Of Adrenaline

“What are the pharmacological actions of adrenaline?”

Dopamine is adrenergic alpha and beta 1 but not beta 2 agonist. In IV low-dose dopamine dilates the blood vessel and increases GFR and sodium secretion.

At a normal dose, it increases the cardiac output and systolic blood pressure with little effect on diastolic blood pressure. It cannot penetrate the blood-brain barrier so no CNS effects.

Hence, it is safe in shock. Dopamine can be used in all types of shocks like cardiogenic, septic, and in severe CHF. Its normal dose is 0.2 to 1 mg/min IV.

The dopamine increases blood pressure and causes urine output hence it is used in the shock.

“Understanding adrenaline: Mechanisms and effects explained”

Question 2. Classify Sympathomimetic Drugs. Describe Pharmacological Actions, Therapeutic Uses, Adverse effects, And Contraindications Of Adrenaline.
Or
Classify Sympathomatic Agents. Describe Pharmacological Action, Therapeutic Uses, And Contraindications For Adrenaline
Answer:

Pharmacological Actions Of Adrenaline

• Heart: Adrenaline is a cardiac stimulant. It increases heart rate, increases myocardial contractility, increases conduction velocity, and increases cardiac output as well as oxygen consumption. It also increases the excitability and can lead to cardiac arrhythmias.
• Blood vessels: It leads to the constriction of blood vessels of the skin and mucous membranes which have α1 receptors. It also leads to the constriction of mesenteric, renal, pulmonary, and splanchnic blood vessels. It dilates blood vessels of skeletal muscles and coronary blood vessels which have β2 effect.
• Blood pressure: Due to its action on α1 receptors in the heart and blood vessels it leads to an initial rise in blood pressure and this is followed by a gradual fall in blood pressure, due to the action on β2 receptors in skeletal muscles which causes vasodilatation.

“Common pharmacological uses of adrenaline explained”

• Respiratory system: It leads to the rapid relaxation of bronchial smooth muscle due to its action on β2 receptors and has a short duration of action. It also stops the release of inflammatory mediators from mast cells. Due to its vasoconstrictor effect, it reduces secretion and relieves mucosal congestion due to the vasoconstrictor effect produced by α1 receptors.
• Gastrointestinal: Adrenaline causes gut relaxation, decreases motility, and constricts sphincters.
• Eye: Adrenergic drugs cause contraction of radial muscles of the iris thus causing mydriasis. They decrease the aqueous formation and thus decrease intraocular tension.
• CNS: Adrenaline at its therapeutic doses does not cross the blood-brain barrier and so effects on CNS are very less.
• Metabolism: It causes an increase in blood glucose levels by stimulating liver glycogenolysis; reducing the secretion of insulin and by decrease in uptake of glucose by peripheral tissues.

“Importance of adrenaline in emergency medical treatments”

Therapeutic Uses Of Adrenergic Drugs

• Anaphylactic shock and allergic disorders.
• Hypotensive state: Vasopressor agent can be used.
• Neurogenic or cardiogenic shock: Dopamine or dobutamine is preferred.
• Congestive heart failure: Short-term use in the decompensated state, i.e. dopamine and dobutamine.
• Cardiac arrest: IV adrenaline is used.
• Partial or complete heart block: Ephedrine or isoprenaline can be used.
• Along with local anesthetic adrenaline is used.
• Control of local bleeding: Adrenaline, Phenylephiderine, and ephedrine is used.

“Treatment options using adrenaline in emergencies”

• Nasal decongestant in cold rhinitis: Phenylephiderine, xylometazoline, oxymetazoline are used.
• Stokes­Adam syndrome: IV adrenaline is used
• Bronchial asthma: Beta-2 agonist.
• Mydriatics: Phenylephiderine decreases intraocular tension.
• Obesity: Anorectics like fenfluramine can be used for a short period.
• Uterine relaxant: Isoxsuprine, salbutamol, turbutaline.
• Insulin hypoglycemia: Adrenaline may be used.
• Parkinsonism and hypokinetic children: Amphetamines can be used.

“Techniques for managing symptoms of adrenaline overuse”

Adverse Effects Of Adrenaline

• On SC or IM administration it causes transient restlessness palpitation, anxiety, headache, pallor, and tremors.
• On IV administration it causes the following adverse effects, i.e.
  • Cerebral hemorrhage
  • Sudden rise in blood pressure
  • Ventricular tachycardia/fibrillation
  • Angina
  • Myocardial infarction.

“Complications of delaying adrenaline effect management”

Contraindication

Adrenaline is contraindicated in hypertensive, hyperthyroid, and in angina patients.
Adrenaline mixed with the local anesthetic should be used very cautiously for dental anesthesia in patients with heart disease.
It should not be given during anesthesia with halothane and to patients receiving beta-blockers as cerebral hemorrhage due to its unopposed action on vascular alpha-1 receptors.