Question
Adrenaline
Answer
Adrenaline (epinephrine) is a direct-acting sympathomimetic acting on alpha-1, beta-1, and beta-2 receptors.
Actions: alpha-1 — vasoconstriction (skin, mucosa, splanchnic bed); beta-1 — increased heart rate and force of contraction; beta-2 — bronchodilation and vasodilation in skeletal muscle. Net effect on blood pressure: raises systolic, may lower diastolic (beta-2 vasodilation at low doses).
Uses: anaphylactic shock (drug of choice — reverses hypotension, bronchospasm, and laryngeal edema simultaneously), cardiac arrest (restores spontaneous circulation), added to local anesthetics to prolong action and reduce systemic absorption, superficial bleeding control (topical).
Adverse effects: anxiety, tremor, palpitations, arrhythmias, hypertension (risk of cerebral hemorrhage), can precipitate angina in ischemic heart disease.

