CHOLINE is a basic constituent of lecithin that is found in many plants and animal organs. Choline was officially recognized as an essential nutrient by the Institute of Medicine in 1998.1 Its role in the body is complex. It is needed for neurotransmitter synthesis (acetylcholine), cell-membrane signaling (phospholipids), lipid transport (lipoproteins), and methyl-group metabolism (homocysteine reduction). It is the major dietary source of methyl groups via the synthesis of S-adenosylmethionine (AdoMet). At least 50 AdoMet-dependent reactions have been identified in mammals, and it is likely that the number is much higher. Choline is required to make the phospholipids phosphatidylcholine, lysophosphatidylcholine, choline plasmalogen, and sphingomyelin—essential components for all membranes. It plays important roles in brain and memory development in the fetus and appears to decrease the risk of the development of neural tube defects. The importance of choline in the diet extends into adulthood and old age. In a study of healthy adult subjects deprived of dietary choline, 77% of the men and 80% of the postmenopausal women developed signs of subclinical organ dysfunction (fatty liver or muscle damage). Less than half of premenopausal women developed such signs. Ten percent of the subjects studied developed fatty liver, muscle damage, or both when they consumed the Adequate Intake (AI) of choline. The damage was reversed when they consumed a high-choline diet. Plasma choline concentration has been found to vary in response to diet, decreasing approximately 30 percent in humans fed a choline-deficient diet for 3 weeks. Based on estimated dietary intakes and studies reporting liver damage with lower choline intakes, the Institute of Medicine, Food and Nutrition Board set the AI for choline at 425 milligrams/per day for women aged 19 and older, and 550 milligrams/per day for men aged 19 and older.

Rapacuronium bromide (RAPLON), a nondepolarizing neuromuscular blocking agent, is a negative allosteric modulator of muscarinic acetylcholine receptors. Rapacuronium bromide is indicated as an adjunct to general anesthesia to facilitate tracheal intubation and to provide skeletal muscle relaxation during surgical procedures. There were no specific pharmacokinetic studies conducted to examine the drug-drug interactions of RAPLON. Due to the risk of fatal bronchospasm, it was withdrawn from the United States market less than 2 years after its FDA approval.

Cholesterol is a sterol (a combination steroid and alcohol) and a lipid found in the cell membranes of all body tissues, and transported in the blood plasma of all animals. The high level of cholesterol in the blood is a marker of hypercholesterolemia, also called dyslipidemia. As a part of homeopathic product, it helps to support general liver and gallbladder health, and is used for temporary relief of symptoms related to adrenal glands such as fatigue and low energy. Cholesterol binds to and affects the gating of a number of ion channels such as the nicotinic acetylcholine receptor (nAChR) Inwardly-rectifying K+ channels (Kir); Transient receptor potential vanilloid 1 channels (TRPV1) and Large-conductance Ca2+-sensitive voltage-gated K+ channels (BK). It was shown the new mechanistic insights into the role of cholesterol in the regulation of nAChR, showing that cholesterol regulates the channels by two distinct mechanisms: stabilization of the channels in a resting state that depends on specific lipid-protein interactions and facilitation of the transitions between uncoupled and coupled states that depends on the hydrophobic thickness of the membrane

Pipecuronium is a piperazinyl androstane derivative, which is a non-depolarizing neuromuscular blocking agent, which was approved under brand name arduan for injection. It is a long-acting neuromuscular blocking agent, indicated as an adjunct to general anesthesia, to provide skeletal muscle relaxation during surgery. Arduan can also be used to provide skeletal muscle relaxation for endotracheal intubation. Pipecuronium undergoes very little metabolism and is excreted by the kidney and the liver. Owing to its relatively long duration of action and to the residual postoperative neuromuscular block (RPONB), the use of pipecuronium was discontinued in the United States and in several European countries. Because of its excellent safety profile, the use of pipecuronium has been maintained in several countries including China, Russia, Brazil, and Hungary, among others. Its safe use, however, is dependent on the availability of a reliable reversal drug. Although widely used, there are concerns with the use of neostigmine for reversal. Arduan is a powerful competitive antagonist of acetylcholine, since it can bind pre- and postsynaptic (N1) receptors of the transmitters.

Levamisole (the trade name Ergamisol), an anthelminthic drug with immunological properties. It also has antitumor activity when administered with 5-fluorouracil in patients with Duke's C colorectal carcinoma; however, this use was discontinued. The mechanism of the antitumor effect is unknown but has been postulated to be related to levamisole's immunomodulatory properties. Levamisole can stimulate antibody formation to various antigens, enhance T-cell responses by stimulating T-cell activation and proliferation, potentiate monocyte and macrophage functions including phagocytosis, chemotaxis and increases motility, adherence, and chemotaxis. Levamisole inhibits alkaline phosphatase and possesses cholinergic activity. The mechanism of action of levamisole as an antiparasitic agent, for example, to treat ascariasis, relates to its agonistic activity to L-subtype nicotinic acetylcholine receptors in nematode muscles. In addition, levamisole was studied for preventing relapses of the steroid-sensitive idiopathic nephrotic syndrome (SSINS). It was shown, that alone or in combination with steroids, the drug can prolong the time to relapse and prevented recurrence during one year of treatment. However, these studies also were also discontinued.

Diphenidol, a nonphenothiazinic antiemetic agent used primarily in patients with Meniere disease and labyrinthopathies to treat vomiting and vertigo, is considered to be a relatively safe drug. Since it was first approved in the United States in 1967, this drug has been widely used in Latin America and Asia and has contributed to sporadic suicidal and accidental poisonings in mainland China and Taiwan. The mechanism by which diphenidol exerts its antiemetic and antivertigo effects is not precisely known. It is thought to diminish vestibular stimulation and depress labyrinthine function and as an antimuscarinic agent. An action on the medullary chemoreceptive trigger zone may also be involved in the antiemetic effect. Diphenidol has no significant sedative, tranquilizing, or antihistaminic action. It has a weak peripheral anticholinergic effect. Diphenidol is used to relieve or prevent nausea, vomiting, and dizziness caused by certain medical problems.

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.

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.

Methyl anisotropinium (Anisotropine methylbromide) is a quaternary ammonium compound. Its use as treatment adjunct in peptic ulcer has been replaced by the use of more effective agents. Depending on the dose, anisotropine methylbromide may reduce the motility and secretory activity of the gastrointestinal system, and the tone of the ureter and urinary bladder and may have a slight relaxant action on the bile ducts and gallbladder. In general, smaller doses of anisotropine methylbromide inhibit salivary and bronchial secretions, sweating, and accommodation; cause dilatation of the pupil; and increase the heart rate. Larger doses are required to decrease motility of the gastrointestinal and urinary tracts and to inhibit gastric acid secretion. Methyl anisotropinium inhibits the muscarinic actions of acetylcholine on structures innervated by postganglionic cholinergic nerves as well as on smooth muscles that respond to acetylcholine but lack cholinergic innervation. These postganglionic receptor sites are present in the autonomic effector cells of the smooth muscle, cardiac muscle, sinoatrial and atrioventricular nodes, and exocrine glands. It is used in conjunction with antacids or histamine H2-receptor antagonists in the treatment of peptic ulcer, to reduce further gastric acid secretion and delay gastric emptying.

Biperiden, sold under the brandname Akineton was used as an adjunct in the therapy of all forms of parkinsonism (postencephalitic, arteriosclerotic and idiopathic). Was also useful in the control of extrapyramidal disorders due to central nervous system drugs such as phenothiazines and other groups of psychotropics. Biperiden is a weak peripheral anticholinergic agent. It has, therefore, some antisecretory, antispasmodic and mydriatic effects. In addition, biperiden possesses nicotinolytic activity. 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 biperiden is considered to relate to competitive antagonism of acetylcholine at cholinergic receptors in the corpus striatum, which then restores the balance. Atropine-like side effects such as dry mouth; blurred vision; drowsiness; euphoria or disorientation; urinary retention; postural hypotension; constipation; agitation; disturbed behavior may been seen. Only limited pharmacokinetic studies of biperiden in humans are available.