Adrenergic release inhibitors

Guanethidine is an antihypertensive drug that reduces the release of catecholamines, such as norepinephrine. Guanethidine is transported across the sympathetic nerve membrane by the same mechanism that transports norepinephrine itself (NET, uptake 1), and uptake is essential for the drug's action. Once guanethidine has entered the nerve, it is concentrated in transmitter vesicles, where it replaces norepinephrine. It may also inhibit the release of granules by decreasing norepinephrine.

Bretylium (also bretylium tosylate) is an antiarrhythmic agent. It blocks the release of noradrenaline from nerve terminals. In effect, it decreases output from the peripheral sympathetic nervous system. It also acts by blocking K+ channels and is considered a class III antiarrhythmic. The dose is 5–10 mg/kg and side effects are high blood pressure followed by low blood pressure and ventricular ectopy.

Bethanidine (or betanidine) is a sympatholytic drug.

Guanadrel is an antihypertensive agent. It is used in the form of its sulfate.

Debrisoquine is a derivative of guanidine. It is an antihypertensive drug similar to guanethidine. Debrisoquine is frequently used for phenotyping the CYP2D6 enzyme, a drug-metabolizing enzyme.

Guanoxan is a sympatholytic drug that was marketed as Envacar by Pfizer in the UK to treat high blood pressure. It was not widely used and was eventually withdrawn from the market due to liver toxicity.

Guanoclor (INN), also known as guanochlor, is a sympatholytic drug. It is known to bind to non-adrenergic sites in pig kidney membranes.

Guanazodine is an anti-hypertensive sympatholytic drug.