Levomepromazine (also known as methotrimeprazine) is a phenothiazine neuroleptic drug. It is sold in many countries under the generic name (levomepromazine) or under brand names such as Nozinan, Detenler and many more. Levomepromazine is an antipsychotic drug is commonly used as an antiemetic to alleviate nausea and vomiting in palliative care settings particularly in terminal illness. Levomepromazine is a phenothiazine with pharmacological activity similar to that of both chlorpromazine and promethazine. It has the histamine-antagonist properties of the antihistamines together with central nervous system effects resembling those of chlorpromazine. Levomepromazine's antipsychotic effect is largely due to its antagonism of dopamine receptors in the brain. In addition, it can block 5HT2 receptors and some others, like histamine, serotonin.

Betahistine is an orally administered, centrally acting histamine H1 receptor agonist with partial H3 antagonistic activity. It is proposed that betahistine may reduce peripherally the asymmetric functioning of the sensory vestibular organs in addition to increasing vestibulocochlear blood flow by antagonising local H3 heteroreceptors. Betahistine acts centrally by enhancing histamine synthesis within tuberomammillary nuclei of the posterior hypothalamus and histamine release within vestibular nuclei through antagonism of H3 autoreceptors. This mechanism, together with less specific effects of betahistine on alertness regulation through cerebral H1 receptors, should promote and facilitate central vestibular compensation. Betahistine is used to treat the symptoms associated with Ménière's disease, a condition of the inner ear which causes, vertigo (dizziness), tinnitus (ringing in the ears), hearing loss.

Methixene is a tertiary antimuscarinic with actions similar to those of atropine; it also has antihistaminic and direct antispasmodic properties. It is used for the symptomatic treatment of parkinsonism, including the alleviation of the extrapyramidal syndrome induced by other drugs such as phenothiazines, but, like other antimuscarinics, it is of no value against tardive dyskinesias. Metixene has been discontinued. Parkinsonism is thought to result from an imbalance between the excitatory (cholinergic) and inhibitory (dopaminergic) systems in the corpus striatum. The mechanism of action of centrally active anticholinergic drugs such as metixene is considered to relate to competitive antagonism of acetylcholine at muscarinic receptors in the corpus striatum, which then restores the balance.

CHLORAL BETAINE, a chemical complex of chloral hydrate and betaine, is a nonbarbiturate sedative and hypnotic. It is indicated for sleep induction, preoperative sedation, and daytime sedation. CHLORAL BETAINE is converted to chloral hydrate in the body and its action on the central nervous system is identical with that of chloral hydrate.

Chlorprothixene (Taractan, Tarasan, Truxal) is a thioxanthine derivative developed by Lundbeck for the treatment of psychotic disorders. The drug exerts its activity by binding to and inhibiting serotonin receptors, dopamine receptors, muscarinic acetylcholine receptor, histamine H1 receptor and alpha1-adrenergic receptor.

Methysergide is an oral, synthetic ergot alkaloid, structurally related to the oxytocic agent methylergonovine and to the potent hallucinogen LSD. Methysergide is used prophylactically to reduce the frequency and intensity of severe vascular headaches. Although methysergide is an ergot alkaloid, it is a weak vasoconstrictor and oxytocic. Methysergide is a more potent antagonist of peripheral serotonin receptors than other ergot alkaloids. Methysergide is not just a 5HT2 antagonist, it is also a 5HT1 agonist. Although methysergide and sumatriptan both stimulate serotonin receptors centrally, methysergide is intended for prophylaxis while sumatriptan is indicated for treatment of an acute attack. Methysergide was approved by the FDA in 1962. Methysergide was formerly used for prophylaxis of cluster headaches/migraine headaches, but is no longer recommended due to retroperitoneal/retropulmonary fibrosis.

Methoxyflurane is an inhalation anesthetic. Methoxyflurane was used for surgical, obstetric, or dental anesthesia, but was withdrawn from US market due to safety concerns, but is still in use in Australia and other countries. Methoxyflurane induces muscle relaxation and reduces pains sensitivity by altering tissue excitability by decreasing the extent of gap junction mediated cell-cell coupling and altering the activity of the channels that underlie the action potential.

Mephenoxalone is an oxazolidinone compound. It is a skeletal muscle relaxant as well as anxiolytic. Mephenoxalone is indicated for the treatment of muscle spasms.

Mebutamate (Capla, Dormate) is a biscarbamate drug that has anxiolytic, sedative, and antihypertensive effects. It is marketed under many trade names, including Capla and Dormate. Its preparation was reported in a 1959 US patent to Carter Products. It is less well known that mebutamate is also hypnotic. In a 1967 study, L. Tetreault, P. Richer, and J. M. Bordeleau in Montreal found that, at a dose of 600 mg, mebutamate has hypnotic properties that “affect the duration and quality of sleep induction, and the duration and quality of sleep, without disturbing the state of the subject upon awakening and during the morning.” A higher dose (900 mg) did not change the overall effect, which was “consistently between that of secobarbital at 200 mg and 100 mg.” The authors did not observe any significant side effects. Mebutamate is one of many GABAergic drugs which act via allosteric agonism of the GABAA receptor at the β-subreceptor similar to barbiturates. In contrast, benzodiazepines act at the α-subreceptor. As such, carbamates and barbiturates, possess analgesic properties which the benzodiazepine class of drugs does not.

Acetophenazine (Tindal) is an antipsychotic drug of moderate-potency. Used in the treatment of disorganized and psychotic thinking. Acetophenazine (Tindal) is also used to help treat false perceptions (e.g. hallucinations or delusions). Acetophenazine acts as an antagonist of dopaminergic D2 receptors in the brain. Acetophenazine exhibited modest androgen receptor binding and antiandrogen activity.