Trimethaphan (or Trimethaphan camsylate), a ganglionic blocking agent and an antihypertensive drug, was marketed under the brand name Arfonad. Arfonad is indicated to induce systemic arterial hypotension in patients undergoing major surgery and to treat severe systemic hypertension, and in the emergency treatment of pulmonary edema in patients with pulmonary hypertension associated with systemic hypertension. Trimethaphan prevents stimulation of postsynaptic receptors by competing with acetylcholine for these receptor sites. Additional effects may include direct peripheral vasodilation and release of histamine. This drug was discontinued because of the competition from newer drugs that are more selective in their actions and effects.