Xanomeline (LY-246,708) is an orthosteric muscarinic acetylcholine receptor (mAChR) agonist, often referred to as M1/M4-preferring. It is also known to act as a M5 receptor antagonist. Xanomeline was studied in clinical trials phase I in schizophrenia. In Phase II clinical trials in Alzheimer’s patients, xanomeline significantly improved several measures of cognitive function, yet produced unwanted side effects that limited patient compliance. The side effects seem to be associated with rapid metabolism of the alkyloxy side chain following oral administration, resulting in a nonselective, yet active compound with limited therapeutic utility. Despite a second Phase II clinical trial with a patch formulation, the liabilities of xanomeline still outweigh its benefits.

Revefenacin (trade name Yupelri is a long-acting muscarinic antagonist developed by Mylan Ireland ltd for the treatment of chronic obstructive pulmonary disease (COPD). It has similar affinity to the subtypes of muscarinic receptors M1 to M5. In the airways, it exhibits pharmacological effects through inhibition of M3 receptor at the smooth muscle leading to bronchodilation. The competitive and reversible nature of antagonism was shown with human and animal origin receptors and isolated organ preparations. In preclinical in vitro as well as in vivo models, prevention of methacholine- and acetylcholine-induced bronchoconstrictive effects was dose-dependent and lasted longer than 24 hours.

Fesoterodine (trade name Toviaz) is a prodrug of 5-hydroxymethyl tolterodine, which is also the active metabolite of tolterodine. Fesoterodine and its active metabolites are nonsubtype selective, competitive antagonists of human muscarinic receptors, but 5-hydroxymethyl tolterodine has greater potency than the parent compound. A prodrug approach was necessary for systemic bioavailability of 5-hydroxymethyl tolterodine after oral administration. Fesoterodine was originated by Schwarz Pharma (later a subsidiary of UCB) and is being developed by Pfizer for the treatment of overactive bladder and urinary urge incontinence. The agent is launched in several countries for the treatment of overactive bladder, including the US, Japan, Canada, Europe and Asia.

Solifenacin is a competitive muscarinic acetylcholine receptor antagonist. The binding of acetylcholine to these receptors, particularly the M3 receptor subtype, plays a critical role in the contraction of smooth muscle. By preventing the binding of acetylcholine to these receptors, solifenacin reduces smooth muscle tone in the bladder, allowing the bladder to retain larger volumes of urine. It is FDA approved for the treatment of overactive bladder with symptoms of urge urinary incontinence, urgency, and urinary frequency. Common adverse reactions include constipation, Xerostomia. Inhibitors of CYP3A4 may increase the concentration of Solifenacin. Vice versa, CYP3A4 Inducers decrease concentration.

Ipratropium (ipratropium bromide, ATROVENT® HFA) is a muscarinic antagonist structurally related to atropine but often considered safer and more effective for inhalation use. It is indicated for the maintenance treatment of bronchospasm associated with chronic obstructive pulmonary disease (COPD), including chronic bronchitis and emphysema. Ipratropium (ipratropium bromide, ATROVENT® HFA) is an anticholinergic (parasympatholytic) agent which, based on animal studies, appears to inhibit vagally-mediated reflexes by antagonizing the action of acetylcholine, the transmitter agent released at the neuromuscular junctions in the lung. Anticholinergics prevent the increases in intracellular concentration of Ca2+ which is caused by interaction of acetylcholine with the muscarinic receptors on bronchial smooth muscle.

Glycopyrrolate is a synthetic anticholinergic agent with a quaternary ammonium structure. Glycopyrrolate is a muscarinic competitive antagonist used as an antispasmodic, in some disorders of the gastrointestinal tract, and to reduce salivation with some anesthetics. Glycopyrrolate binds competitively to the muscarinic acetylcholine receptor. Like other anticholinergic (antimuscarinic) agents, it inhibits the action of acetylcholine on structures innervated by postganglionic cholinergic nerves and on smooth muscles that respond to acetylcholine but lack cholinergic innervation. These peripheral cholinergic receptors are present in the autonomic effector cells of smooth muscle, cardiac muscle, the sinoatrial node, the atrioventricular node, exocrine glands and, to a limited degree, in the autonomic ganglia. Thus, it diminishes the volume and free acidity of gastric secretions and controls excessive pharyngeal, tracheal, and bronchial secretions. Glycopyrrolate antagonizes muscarinic symptoms (e.g., bronchorrhea, bronchospasm, bradycardia, and intestinal hypermotility) induced by cholinergic drugs such as the anticholinesterases. The highly polar quaternary ammonium group of glycopyrrolate limits its passage across lipid membranes, such as the blood-brain barrier, in contrast to atropine sulfate and scopolamine hydrobromide, which are highly non-polar tertiary amines which penetrate lipid barriers easily. Glycopyrrolate is marketed under the brand names Robinul, Robinul Forte, Cuvposa. In October 2015, glycopyrrolate was approved by the FDA for use as a standalone treatment for Chronic obstructive pulmonary disease (COPD), as Seebri Neohaler.

Methscopolamine bromide is an anticholinergic agent used along with other medications to treat peptic ulcers by reducing stomach acid secretion. Methscopolamine is also commonly used as a drying agent, to dry up post-nasal drip, in cold, irritable bowel syndrome and allergy medications. Methscopolamine binds to M1-M5 isoforms of muscarinic receptors.

Trihexyphenidyl (Artane, Apo-Trihex, Parkin, Pacitane), also known as benzhexol and trihex has been in clinical usage for decades.It is an anticholinergic used in the symptomatic treatment of all etiologic groups of parkinsonism and drug induced extrapyramidal reactions (except tardive dyskinesia). Trihexyphenidyl possesses both anticholinergic and antihistaminic effects, although only the former has been established as therapeutically significant in the management of parkinsonism. Trihexyphenidyl is a selective M1 muscarinic acetylcholine receptor antagonist. It is able to discriminate between the M1 (cortical or neuronal) and the peripheral muscarinic subtypes (cardiac and glandular). Trihexyphenidyl partially blocks cholinergic activity in the CNS, which is responsible for the symptoms of Parkinson's disease. It is also thought to increase the availability of dopamine, a brain chemical that is critical in the initiation and smooth control of voluntary muscle movement. Trihexyphenidyl is indicated for the treatment of parkinson's disease and extrapyramidal reactions caused by drugs.

NGX267 is a partial muscarinic receptor agonist with functionally specific M1 and M3 receptor activity, developed by Torrey Pines Therapeutics(TPTX) for the treatment of Xerostomia, Alzheimer’s disease and cognitive deficits in schizophrenia. NGX-267 had been in phase II clinical trials for the treatment of Xerostomia, however, all researchers on this drug candidate were discontinued.

Esaprazole, also known as hexaprazole, was developed in the 1980s as a drug for the treatment of gastric and duodenal ulcers. Esaprazole exerts a dose-dependent cytoprotective effect on the gastric mucosa in man. It was shown to have a dose-dependent antisecretory activity, which was particularly evident on secretion volume and acid output. Esaprazole completed phase II clinical trials with only a few minor side effects being reported, but was shown to be less effective than Cimetidine and Ranitidine at healing ulcers. Esaprazole is a weak sigma opioid receptor and muscarinic acetylcholine receptors M3 and M5 ligand. Esaprazole analogs with many compounds showing neuroprotective properties.