Pargyline is an irreversible selective monoamine oxidase (MAO)-B inhibitor, which possesses higher selectivity to this isoform in comparison with MAO-A. It was approved under brand name eutonyl for the treatment hypertension, but then this drug was discontinued.

ETRYPTAMINE (MONASE®), similar to the hallucinogenic tryptamines, is an inhibitor of monoamine oxidase, introduced for use as an antidepressant. It was withdrawn from the market due to problems with agranulocytosis and other side effects. However, it's activity is still under scientific investigation.

Nialamide is a non-selective, irreversible monoamine oxidase inhibitor of the hydrazine class. It was previously used as an antidepressant (trade name Niamid) but was withdrawn by Pfizer in 1963 due to the risk of hepatotoxicity.

Demecarium (HUMORSOL®) is an indirect-acting parasympathomimetic agent, also known as a cholinesterase inhibitor and anticholinesterase. Cholinesterase inhibitors prolong the effect of acetylcholine, which is released at the neuroeffector junction of parasympathetic postganglion nerves, by inactivating the cholinesterases that break it down. Application of demecarium (HUMORSOL®) to the eye produces intense miosis and ciliary muscle contraction due to inhibition of cholinesterase, allowing acetylcholine to accumulate at sites of cholinergic transmission. These effects are accompanied by increased capillary permeability of the ciliary body and iris, increased permeability of the blood-aqueous barrier, and vasodilation. Myopia may be induced or, if present, may be augmented by the increased refractive power of the lens that results from the accommodative effect of the drug. Demecarium (HUMORSOL®) indirectly produces some of the muscarinic and nicotinic effects of acetylcholine as quantities of the latter accumulate.

PHENIPRAZINE is a monoamine oxidase inhibitor of the hydrazine chemical class that was used for the treatment of depression, schizophrenia, and also as a long-acting coronary vasodilator in patients suffering from angina pectoris. PHENIPRAZINE was discontinued due to toxicity concerns such as jaundice, amblyopia, and optic neuritis.

FLUMETHIAZIDE, a benzothiadiazine, is a diuretic agent used for the treatment of arterial hypertension.

Ethoxzolamide is a carbonic anhydrase I inhibitor. It is used in the treatment of glaucoma and duodenal ulcers, and as a diuretic. Ethoxzolamide was marketed under trade name Cadrase, but is now discontinued.

Ambenonium is a cholinesterase inhibitor with all the pharmacologic actions of acetylcholine, both the muscarinic and nicotinic types. It was marketed under the brand name Mytelase, but was withdrawn from the market in the United States in 2010. Ambenonium, similar to pyridostigmine and neostigmine, is used for the treatment of muscle weakness and fatigue in people with myasthenia gravis.Ambenonium exerts its actions against myasthenia gravis by competitive, reversible inhibition of acetylcholinesterase. The disease myasthenia gravis occurs when the body inappropriately produces antibodies against acetylcholine receptors, and thus inhibits proper acetylcholine signal transmission (when acetylcholine binds to acetylcholine receptors of striated muscle fibers, it stimulates those fibers to contract). Ambenonium reversibly binds acetylcholinesterase at the anionic site, which results in the blockage of the site of acetycholine binding, thereby inhibiting acetylcholine hydrolysis and enhancing cholinergic function through the accumulation of acetycholine at cholinergic synpases. In turn this facilitates transmission of impulses across the myoneural junction and effectively treats the disease.

Iproniazid is a non-selective, irreversible monoamine oxidase inhibitor (MAO) of the hydrazine class. It was originally developed for the treatment of Tuberculosis, but in 1952, its antidepressant properties were discovered when researchers noted that patients given isoniazid became inappropriately happy. Iproniazid is no longer clinically prescribed and has been withdrawn due to incidences of hepatotoxicity.

Hexafluorenium inhibits the enzyme cholinesterase in the plasms, but apparently not at the neuromuscular juntion. It also has some nondepolarizing activity (tubocurarine-like) at the postjunctional membrane. In man hexafluorenium potentiates the muscle relaxant effects of succinylcholine. As such, smaller doses of succinylcholine are required and fewer side effects like fasciculations, twitching and postoperative muscle pain are experienced.