Master Alpha Agonists with Picmonic for Medicine

Norepinephrine is a catecholamine and α1, α2 agonist with some β1 activity. It is primarily indicated for acute hypotension, especially in septic shock.

Norepinephrine is a first-line vasopressor used in septic shock to rapidly increase blood pressure. It acts primarily as an α1 agonist, causing peripheral vasoconstriction, and has some β1 activity, which supports cardiac output. This combination raises mean arterial pressure without significantly increasing heart rate, helping to maintain organ perfusion in critically ill patients.

Norepinephrine raises blood pressure primarily through α1-mediated vasoconstriction while providing modest β1 support to cardiac output. In septic shock, it does not inherently decrease renal perfusion; instead, by restoring mean arterial pressure, norepinephrine often preserves or improves renal blood flow and kidney function, depending on volume status and overall hemodynamics.

Phenylephrine is a selective α1 agonist that is indicated for use as a decongestant, vasopressor, and mydriatic.

Phenylephrine is a selective α1-adrenergic agonist that increases blood pressure through peripheral vasoconstriction. It is not recommended as a first-line vasopressor in septic shock and is not equivalent to norepinephrine, as it lacks β1 activity and may reduce stroke volume. Its use is reserved for specific situations, such as septic shock with significant tachyarrhythmias where β-adrenergic stimulation is undesirable.

It is used orally or intranasally to treat nasal congestion by vasoconstricting the nasal mucosa.

Ephedrine is an indirect sympathomimetic that releases stored catecholamines. It is used to treat hypotension, urinary incontinence, and nasal congestion.

Ephedrine is commonly used as a decongestant via α1-mediated vasoconstriction.

Ephedrine improves urinary continence by increasing urethral sphincter tone through α1 receptor activation.

Ephedrine is commonly used to treat hypotension, and administration is often seen in surgical or obstetric procedures.

Epinephrine is a catecholamine agonist at α1, α2, β1, and β2 receptors. It is used for anaphylaxis, asthma, and hypotension.

In anaphylaxis, epinephrine vasoconstricts to reverse hypotension and edema. In asthma, it acts as a bronchodilator via β2 stimulation when specific β2 agonists are unavailable.

Epinephrine increases blood pressure through α1-mediated peripheral vasoconstriction and β1-mediated cardiac stimulation, enhancing both systemic vascular resistance and cardiac output.