Used as an adjunct in the management of cardiac arrest and during cardiopulmonary resuscitation (CPR). Intracardiac puncture and intramyocardial administration of adrenaline may be beneficial when external cardiac compression and attempts to restore circulation through electrical defibrillation or pacemaker support are unsuccessful. Adrenaline increases blood pressure, heart rate, air passage, and blood glucose levels. It stimulates cardiac activity and helps reduce allergic responses by lowering histamine-induced inflammation. Because of these effects, it is widely used in treating allergic and anaphylactic reactions. Adrenaline is the preferred treatment for anaphylactic shock and should be given immediately when severe allergic symptoms appear. It is also indicated in life-threatening asthma cases where ventilation is failing and the condition worsens despite nebulizer therapy.

Adrenaline is a direct-acting sympathomimetic agent that works on both alpha and beta adrenoceptors. Its overall effect depends on the dose and may be influenced by homeostatic reflex mechanisms. In resuscitation, it enhances the effectiveness of basic life support and acts as a positive cardiac inotrope. Its major actions include raising systolic blood pressure through arterial and venous vasoconstriction (alpha₁ effect), lowering diastolic pressure, causing tachycardia, and increasing blood glucose levels. Adrenaline acts rapidly and has a short duration of effect. After intravenous administration, its half-life is approximately ৫–১০ minutes. It is quickly distributed to organs such as the heart, spleen, glandular tissues, and adrenergic nerves. The drug is rapidly metabolized in the liver and other tissues through oxidative deamination and O-methylation, followed by reduction or conjugation with glucuronic acid or sulphate. Up to ৯০% of an IV dose is eliminated in the urine as metabolites, and about ৫০% is bound to plasma proteins.

The effects of epinephrine are similar to the stimulation of adrenergic nerves. It acts on both alpha and beta receptor sites of sympathetic effector cells. Its most significant actions occur on the beta receptors of the heart, vascular system, and other smooth muscles. When administered rapidly by intravenous injection, it causes a quick rise in blood pressure, mainly systolic, by (1) directly stimulating the cardiac muscle to increase the force of ventricular contraction, (2) raising the heart rate, and (3) constricting the arterioles in the skin, mucosa, and splanchnic regions of circulation.

When administered slowly via intravenous injection, epinephrine generally results in only a moderate increase in systolic pressure and a decrease in diastolic pressure. Although there may be some rise in pulse pressure, there is usually little to no significant increase in mean blood pressure. Therefore, the compensatory reflex mechanisms activated by a marked rise in blood pressure do not significantly oppose the direct cardiac effects of epinephrine, unlike catecholamines that primarily act on alpha receptors.

Cardiac arrest:

• Intravenous injection: 1 mg injection repeated every 2-3 minutes as necessary.
• Endotracheal: 2-3 mg via an endotracheal tube, repeated as necessary.
• Intracardiac: 0.1 to 1 mg, direct into the atrium of the heart.
• Intraspinal: Usual dose is 0.2 to 0.4 mg added to anesthetic spinal fluid mixture (to prolong anesthetic action by limiting absorption).

Anaphylaxis, asthma or severe bronchospasm:

• Adult dose is 0.25 0.5 mg. It may be repeated at 5 minutes intervals until perfusion and respiratory status normalizes.
• In case of dose dilution: 1 mg of Adrenaline to be diluted in 9 ml Normal Saline.

Children: Initially 10 mcg/kg body weight, not to exceed 250 mcg. May be repeated every 3-5 minutes if necessary.
Subsequent doses should be 100 mcg/kg.

Concurrent use of Adrenaline with high doses of digitalis, mercurial diuretics, or other medications that increase cardiac sensitivity to arrhythmias is not advised. The adverse reactions of Adrenaline can be enhanced by tricyclic antidepressants, certain antihistamines such as Diphenhydramine, Tripelennamine, Chlorpheniramine, and also by L-thyroxine Sodium.

Hypertension, arteriosclerosis, coronary artery disease, and hyperthyroidism. It should not be administered to patients who are receiving monoamine oxidase inhibitors.

Frequently observed side effects include anxiety, restlessness, dizziness, headache, palpitations, rapid heartbeat, tremors, weakness, and a sensation of coldness in the extremities. These effects may occur even at low doses and are more pronounced when used along with local anesthetics.

Pregnancy Category C. It can cross the placenta and is also excreted into breast milk. Adrenaline should be used during pregnancy only when the expected benefit justifies the potential risk to the fetus. Since it is excreted in breast milk, its use is not recommended during breastfeeding due to the possibility of adverse effects in infants.

The solution should not be used if it appears pinkish, darker than slightly yellow, or contains any precipitate. Adrenaline is easily degraded by alkalis and oxidizing substances. These include Oxygen, Chlorine, Iodine, Permanganates, Chromates, Nitrites, and salts of easily reducible metals, particularly Iron. It should not be mixed with Sodium bicarbonate, as this leads to oxidation into adrenochrome and polymer formation. Administer slowly with caution in elderly patients and in those with ischemic heart disease, hypertension, diabetes mellitus, hyperthyroidism, or psychoneurosis. Use extreme caution in patients with long-standing bronchial asthma and emphysema who have developed degenerative heart disease. Anginal pain may occur when coronary insufficiency exists.

Cardiac arrhythmias progressing to ventricular fibrillation, severe hypertension that may result in pulmonary edema and cerebral hemorrhage. Combined alpha and beta-adrenergic blocking agents such as Labetalol may help counteract the effects of adrenaline, or a beta-blocker may be used for treating supraventricular arrhythmias. Phentolamine may be used to control alpha-mediated effects on peripheral circulation. Rapid-acting vasodilators such as nitrates and Sodium Nitroprusside may also be beneficial. Immediate resuscitation support should be ensured.

Anaphylaxis, Mydriatic and Cycloplegic agents, Other adrenoceptor stimulants, Respiratory stimulants: analeptics

Store below 25°C. Protect from light. Keep out of reach of children.