Selegiline, also known as L-deprenyl, is a substituted phenethylamine, a selective, irreversible inhibitor of Type B monoamine oxidase. Selegiline is available in pill form under many brand names (Eldepryl, Carbex, Atapryl) and is used to reduce symptoms in early-stage Parkinson's disease. Selegiline delays the time point when the L-DOPA (levodopa) treatment becomes necessary from about 11 months to about 18 months after diagnosis, which is beneficial despite not being definitive evidence of neuroprotection. The rationale for adding selegiline to levodopa is to decrease the required dose of levodopa and thus reduce the motor complications of levodopa therapy. Selegiline is also delivered via a transdermal patch (brand name, Emsam) and in this form, Selegiline is used as a treatment for the major depressive disorder. Selegiline (brand name Anipryl) is also used (at extremely high dosages relative to humans) in veterinary medicine to treat the symptoms of Cushing's disease and cognitive dysfunction (Canine Cognitive Dysfunction) in dogs. Side effects of the pill form include, in decreasing order of frequency, nausea, hallucinations, confusion, depression, loss of balance, insomnia, increased involuntary movements, agitation, arrhythmia, slow heart rate, delusions, hypertension, new or increased angina pectoris, and syncope. The main side effects of the patch form for depression included application site reactions, insomnia, diarrhea, and sore throat.

Phenelzine is an irreversible non-selective inhibitor of monoamine oxidase. Although the exact mechanism of action has not been determined, it appears that the irreversible, nonselective inhibition of MAO by phenelzine relieves depressive symptoms by causing an increase in the levels of serotonin, norepinephrine, and dopamine in the neuron. Phenelzine is used for the treatment of major depressive disorder. Has also been used with some success in the management of bulimia nervosa.

Tranylcypromine is a non-hydrazine monoamine oxidase inhibitor with a rapid onset of activity. Tranylcypromine has being marketed under original trade name Parnate, indicated for the treatment of major depressive episode without melancholia. Tranylcypromine irreversibly and nonselectively inhibits monoamine oxidase (MAO). Within neurons, MAO appears to regulate the levels of monoamines released upon synaptic firing. Since depression is associated with low levels of monoamines, the inhibition of MAO serves to ease depressive symptoms, as this results in an increase in the concentrations of these amines within the CNS.

Phentermine is an amphetamine that stimulates neurons to release or maintain high levels of a particular group of neurotransmitters known as catecholamines; these include dopamine and norepinephrine. High levels of these catecholamines tend to suppress hunger signals and appetite. The drug seems to inhibit reuptake of noradrenaline, dopamine, and seratonin through inhibition or reversal of the reuptake transporters. It may also inhibit MAO enzymes leaving more neurotransmitter available at the synapse. Phentermine (through catecholamine elevation) may also indirectly affect leptin levels in the brain. It is theorized that phentermine can raise levels of leptin which signal satiety. It is also theorized that increased levels of the catecholamines are partially responsible for halting another chemical messenger known as neuropeptide Y. This peptide initiates eating, decreases energy expenditure, and increases fat storage. Phentermine is indicated in the management of exogenous obesity as a short term (a few weeks) adjunct in a regimen of weight reduction based on caloric restriction. Phentermine hydrochloride is a sympathomimetic amine with pharmacologic activity similar to the prototype drugs of this class used in obesity, the amphetamines. Actions include central nervous system stimulation and elevation of blood pressure. Tachyphylaxis and tolerance have been demonstrated with all drugs of this class in which these phenomena have been looked for.

Indantadol (previously known as CHF-3381) is an oral and noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist and reversible monoamine oxidase-A (MAO-A) inhibitor that is being developed by Vernalis plc, under license from Chiesi Farmaceutici SpA, for the potential treatment of neuropathic pain. In preclinical studies, indantadol exhibited neuroprotective effects after kainate-induced seizures and displayed anticonvulsant and antihyperalgesic activity. Indantadol also caused a dose-dependent decrease in exploratory motility. In a human heat-capsaicin-induced pain model, indantadol at a dose of 500 mg effectively reduced the area of secondary hyperalgesia. The tolerability profile of the drug at single doses up to 600 mg and twice-daily doses up to 400 mg in clinical trials was significantly more favorable than for other NMDA antagonists. Most side effects have been observed to be mild, and include dizziness and asthenia. Indantadol was in phase II clinical trials for the treatment of chronic cough and neuropathic pain. However, these studies had been discontinued.

Alpha methyltryptamine (AMT) is a tryptamine (indole ethylamine) derivative, which was developed in the 1960's by Upjohn with the intention for use as an antidepressant. It was used in Russia under the trade name Indopan for the treatment of Bipolar disorder and some form of depression, but currently not being produced because of serious side effects. In the 1990's, alpha-methyltryptamine became regulated as a Schedule I controlled substance in the United States. Pharmacologically, AMT has high affinity for the serotonin (5-HT) transporter, a number of 5-HT receptors, and potently inhibits reuptake of monoamines dopamine, 5-HT, and norepinephrine reuptake. AMT is also a monoamine oxidase A inhibitor that conceivably could contribute to its pharmacological effect and this drug also the most potent inhibitor of semicarbazide-sensitive amine oxidase (SSAO).

Pirlindole is a selective and reversible inhibitor of monoamine oxidase (MAO) subtype A (MAO-A). It exerts an inhibitory effect on noradrenaline and 5-hydroxytryptamine reuptakes. It has no effect on the dopaminergic and cholinergic systems. It has only a low potential for amplifying tyramine and noradrenaline pressor effect, which makes one expect that it will not be at the basis of a ‘cheese effect’. Pirlindole was approved in some European and non-European countries for the treatment of depression. The antidepressant efficacy and safety of pirlindole have been demonstrated in a number of placebo- and active comparator-controlled studies and are supported by many years of clinical experience in the treatment of depression. The drug's efficacy and safety have also been demonstrated in the treatment of fibromyalgia syndrome. Pirlindole has a favorable tolerability profile, with no deleterious effect on cardiovascular dynamics. The effect of pirlindole on sensorimotor performance relevant to driving a motor vehicle is similar to that of placebo, as pirlindole appears to have an activating rather than a sedating antidepressant profile. Pirlindole prevented qualitative alteration (transformation) in the catalytic activity of membrane-bound type A monoamine oxidases (MAO-A), pathogenetically important for the development of the audiogenic seizures.

Clorgiline is a monoamine oxidase (MAO) inhibitor. Specifically, it is an irreversible and selective inhibitor of MAO-A. Clorgiline was under investigation for antidepressant and anxiolytic potential but has never been marketed, likely due to efficacy concerns. It continues to see routine use as a molecular probe in biomedical research examining a number of neurological disease and cancer models. In addition to inhibiting the MAO-A receptor, it has also been found to bind to the sigma1 receptor, and with high affinity to the I2 imidazoline receptor.

5-(2-Aminopropyl)indole (5-API, 5-IT, PAL-571) is a psychoactive phenethylamine derivative with empathogenic effects used for recreational purposes. 5-(2-Aminopropyl)indole, originally synthesized as a stimulant in the 1960s now joins the list of psychoactive substances and may to be one of the newest MDMA replacements. 5-(2-Aminopropyl)indole acts as a triple monoamine releasing agent and also as selective MAO-A inhibitor.