BW A444U was an experimental

neuromuscular blocking drug Neuromuscular-blocking drugs block neuromuscular transmission at the neuromuscular junction, causing paralysis of the affected skeletal muscles. This is accomplished via their action on the post-synaptic acetylcholine (Nm) receptors. In c ...

skeletal muscle relaxant A muscle relaxant is a drug that affects skeletal muscle function and decreases the muscle tone. It may be used to alleviate symptoms such as muscle spasms, pain, and hyperreflexia. The term "muscle relaxant" is used to refer to two major therapeu ...

in the category of non-depolarizing

neuromuscular-blocking drugs Neuromuscular-blocking drugs block neuromuscular transmission at the neuromuscular junction, causing paralysis of the affected skeletal muscles. This is accomplished via their action on the post-synaptic acetylcholine (Nm) receptors. In cli ...

, intended to be used adjunctively in surgical anesthesia to facilitate endotracheal

intubation Intubation (sometimes entubation) is a medical procedure involving the insertion of a tube into the body. Patients are generally anesthetized beforehand. Examples include tracheal intubation, and the balloon tamponade with a Sengstaken-Blake ...

and to provide skeletal muscle relaxation during surgery or

mechanical ventilation Mechanical ventilation, assisted ventilation or intermittent mandatory ventilation (IMV), is the medical term for using a machine called a ventilator to fully or partially provide artificial ventilation. Mechanical ventilation helps move a ...

. It was synthesized and developed in the early 1980s. BW A444U represented the first-generation of

tetrahydroisoquinoline Tetrahydroisoquinoline (TIQ or THIQ) is an organic compound with the chemical formula C9H11N. Classified as a secondary amine, it is derived from isoquinoline by hydrogenation. It is a colorless viscous liquid that is miscible with most organic s ...

neuromuscular-blocking drug Neuromuscular-blocking drugs block neuromuscular transmission at the neuromuscular junction, causing paralysis of the affected skeletal muscles. This is accomplished via their action on the post-synaptic acetylcholine (Nm) receptors. In cli ...

s that are

nicotinic acetylcholine receptor Nicotinic acetylcholine receptors, or nAChRs, are receptor polypeptides that respond to the neurotransmitter acetylcholine. Nicotinic receptors also respond to drugs such as the agonist nicotine. They are found in the central and peripheral ner ...

antagonists or antinicotinics. It was an intermediate-duration non-depolarizing

or skeletal muscle relaxant. It was synthesized by Mary M. Jackson and James C. Wisowaty, PhD (both chemists within the Chemical Development Laboratories at Burroughs Wellcome Co., Research Triangle Park, NC) in collaboration with John J. Savarese MD (who at the time was an anesthesiologist in the Dept. of Anesthesia,

Harvard Medical School Harvard Medical School (HMS) is the graduate medical school of Harvard University and is located in the Longwood Medical Area of Boston, Massachusetts. Founded in 1782, HMS is one of the oldest medical schools in the United States and is consi ...

at the Massachusetts General Hospital,

Boston Boston (), officially the City of Boston, is the state capital and most populous city of the Commonwealth of Massachusetts, as well as the cultural and financial center of the New England region of the United States. It is the 24th- mo ...

, MA). The drug was tested clinically in the early 1980s, and quickly abandoned from further clinical development after a single clinical study, owing primarily to undesirable effects of histamine release when administered at clinically relevant doses.

References

{{Nicotinic acetylcholine receptor modulators Abandoned drugs Muscle relaxants Nicotinic antagonists Norsalsolinol ethers Pyrogallol ethers Quaternary ammonium compounds