Cisatracurium is a cis-cis isomer of atracurium and five time as potent as atracurium. The drug is approved by FDA and marketed under the name Nimbex. It is indicated as an adjunct to general anesthesia, to facilitate tracheal intubation, and to provide skeletal muscle relaxation due to its antagonistic properties toward nicotinic acetylcholine receptors.

Vecuronium is a neuromuscular blocking agent. Vecuronium operates by competing for the cholinoceptors at the motor end plate thereby exerting its muscle-relaxing properties which are used adjunctively to general anesthesia. Vecuronium is a bisquaternary nitrogen compound that acts by competitively binding to nicotinic cholinergic receptors. The binding of vecuronium decreases the opportunity for acetylcholine to bind to the nicotinic receptor at the postjunctional membrane of the myoneural junction. As a result, depolarization is prevented, calcium ions are not released and muscle contraction does not occur. Vecuronium is indicated as an adjunct to general anesthesia, to facilitate endotracheal intubation and to provide skeletal muscle relaxation during surgery or mechanical ventilation.

Pancuronium (trademarked as Pavulon) is an aminosteroid muscle relaxant with various medical uses. Pancuronium is a typical non-depolarizing curare-mimetic muscle relaxant. It competitively inhibits the nicotinic acetylcholine receptor at the neuromuscular junction by blocking the binding of acetylcholine. It has slight vagolytic activity, causing an increase in heart rate, but no ganglioplegic (i.e., blocking ganglions) activity. It is a very potent muscle relaxant drug, with an ED95 of only 60 µg/kg body weight. The onset of action is relatively slow compared to other similar drugs, in part due to its low dose - an intubating dose takes 3–6 minutes for full effect. Clinical effects (muscle activity lower than 25% of physiological) last for about 100 minutes. The time needed for full (over 90% muscle activity) recovery after single administration is about 120–180 minutes in healthy adults. Pancuronium is used with general anesthesia in surgery for muscle relaxation and as an aid to intubation or ventilation. It does not have sedative or analgesic effects. Side-effects include moderately raised heart rate and thereby arterial pressure and cardiac output, excessive salivation, apnea and respiratory depression, rashes, flushing, and sweating. The muscular relaxation can be dangerous for the seriously ill and it can accumulate leading to extended weakness. Pancuronium is not preferable to long-term use in ICU-ventilated patients. Pancuronium is also used as one component of a lethal injection in the administration of the death penalty in some parts of the United States.

Succinylcholine also known as suxamethonium is a quaternary skeletal muscle relaxant usually used in the form of its halogen salt. It is is indicated under brand name anectine as an adjunct to general anesthesia, to facilitate tracheal intubation, and to provide skeletal muscle relaxation during surgery or mechanical ventilation. Succinylcholine activates the muscle-type nicotinic acetylcholine receptor followed by desensitization. Succinylcholine does not inhibit the presynaptic alpha3beta2 autoreceptor at clinically relevant concentrations, that provides a possible mechanistic explanation for the typical lack of tetanic fade in succinylcholine-induced neuromuscular blockade. Finally, was explored, that cardiovascular side effects (e.g., tachyarrhythmias) of succinylcholine were not mediated via direct activation of the autonomic ganglionic alpha3beta4 subtype because succinylcholine didn’t not activate the neuronal nicotinic acetylcholine receptor (nAChR) subtypes.

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.

Tubocurarine, a naturally occurring alkaloid, is used to treat smoking withdrawl syndrom. Tubocurarine, the chief alkaloid in tobacco products, binds stereo-selectively to nicotinic-cholinergic receptors at the autonomic ganglia, in the adrenal medulla, at neuromuscular junctions, and in the brain. Two types of central nervous system effects are believed to be the basis of Tubocurarine's positively reinforcing properties. A stimulating effect is exerted mainly in the cortex via the locus ceruleus and a reward effect is exerted in the limbic system. At low doses the stimulant effects predominate while at high doses the reward effects predominate. Intermittent intravenous administration of Tubocurarine activates neurohormonal pathways, releasing acetylcholine, norepinephrine, dopamine, serotonin, vasopressin, beta-endorphin, growth hormone, and ACTH. Tubocurarine competes with acetylcholine for post-synaptic nicotinic NM receptors and blocks them.

Dimethyltubocurarine (metocurine) is a non-depolarizing muscle relaxant. It binds to muscle acetylcholine receptor by bridging the to alpha and non-alpha subunits from the ligand binding site. Dimethyltubocurarine was used as an anesthesia adjunct to induce skeletal muscle relaxation and to reduce the intensity of muscle contractions in convulsive therapy.

Alcuronium (diallylnortoxiferine) is a semi-synthetic substance prepared from C-toxiferine I a bis-quaternary alkaloid obtained from Strychnos toxifera. Alcuronium is a neuromuscular blocking (NMB) agent, alternatively referred to as a skeletal muscle relaxant. Alcuronium is used for endotracheal intubation and to produce muscle relaxation in general anesthesia during surgical procedures. The pharmacological action of alcuronium is readily reversed by neostigmine, and it produced little histamine release. The major disadvantage of alcuronium is that it elicits a vagolytic effect produced by a selective atropine-like blockade of cardiac muscarinic receptors.

Gallamine is a synthetic non-depolarizing neuromuscular blocking agent. It has been used to produce relaxation of skeletal muscle during surgery.

Atracurium is an intermediate-duration, nondepolarizing, skeletal muscle relaxant for intravenous administration. It is used, as an adjunct to general anesthesia, to facilitate endotracheal intubation and to provide skeletal muscle relaxation during surgery or mechanical ventilation. Most adverse reactions were suggestive of histamine release. Common side effects include flushing of the skin and low blood pressure. Drugs which may enhance the neuromuscular blocking action of atracurium include: enflurane; isoflurane; halothane; certain antibiotics, especially the aminoglycosides and polymyxins; lithium; magnesium salts; procainamide; and quinidine.