Tubocurarine chloride

White crystalline powder. Easily soluble in water. d-tubocurarine chloride is a derivative of bisbenzyltetrahydroisoquinoline. For a long time, it was considered as a bis-quaternary ammonium base with an optical distance between onium groups (quaternary nitrogen atoms) of 1.5 nm, with the structure depicted in the upper formula.

In 1970, the results of chemical and spectroscopic studies were published, showing that one of the nitrogen atoms of the d-tubocurarine molecule is not quaternary, but tertiary. Thus, d-tubocurarine should not be considered as bis-quaternary, but as a mono-quaternary compound. d-Tubocurarine primarily blocks nicotinic skeletal muscle cholinergic receptors, and to a lesser extent affects the cholinergic receptors of the autonomic nerve nodes. In large doses, this drug also blocks cholinergic receptors of the autonomic nerve nodes, chromaffin tissue of the adrenal glands and carotid glomeruli.

Small doses of d-tubocurarine can cause temporary relaxation of skeletal muscles (relaxation).

In this case, the muscles relax in the following sequence: the muscles of the fingers - eyes - legs - neck - back, then intercostal muscles and diaphragm.

When taking small doses, respiratory arrest may not occur (if nerve transmission to the intercostal muscles and the diaphragm is not blocked), however, when the dose is increased, respiratory arrest occurs; if artificial ventilation is performed, the action of d-tubocurarine gradually passes and natural respiration is restored.

In this case, the restoration of muscle function occurs in the reverse order of their relaxation. With adequate mechanical ventilation, d-tubocurarine does not cause disturbances in the basic functions of the body.

The d-tubocurarine does not have a pronounced direct effect on the cardiovascular system, however, due to the ganglion-blocking effect, it can cause a decrease in blood pressure (usually by 15-20 mm Hg). Normal doses of d-tubocurarine do not significantly affect the central nervous system. It should be borne in mind that d-tubocurarine promotes the release of histamine from the tissues and can sometimes cause spasm of the muscles of the bronchioles. d-tubocurarine is mainly used by anesthetists as a muscle relaxant, which causes muscle relaxation during surgery.

In traumatology, d-tubocurarine is sometimes used to relax muscles during reposition of fragments, reposition of complex dislocations, etc.

For the treatment of spastic paralysis and prolonged convulsive conditions, d-tubocurarine was not widely used mainly due to the short duration of the effect it caused and the complexity of its use (the need to provide artificial ventilation of the lungs.

D-tubocurarine is injected into a vein. The action of the drug develops gradually, usually muscle relaxation begins after 1-1.5 minutes, and the maximum effect occurs after 3-4 minutes.

The average dose for an adult is 15-25 mg, while relaxation lasts 20-25 minutes. However, doses of d-tubocurarine, as well as other muscle relaxants, depend on the anesthesia used. With combined general anesthesia with nitrous oxide, the intravenous administration of d-tubocurarine at a dose of 0.4-0.5 mg / kg causes complete muscle relaxation and apnea lasting 20-25 minutes. Satisfactory relaxation of the abdominal muscles and extremities continues for 20-30 minutes.

If a longer action is required, d-tubocurarine is administered repeatedly, while in connection with the ability to cumulate, each subsequent dose should be 1.5-2 times less than the previous one. Typically, for an operation lasting 2-2.5 hours, 40-45 mg of the drug is spent.

With ether anesthesia, the initial dose of d-tubocurarine is 0.25-0.4 mg / kg.

It should be borne in mind that the effect of d-tubocurarine is somewhat enhanced when applied after dithylin .

D-tubocurarine is administered only after transferring the patient to mechanical ventilation.

The plants from which d-tubocurarine is obtained do not grow in Russia. The drug is produced abroad.

D-tubocurarine antagonists are proserin and galantamine, which are usually given with atropine . Tubocurarine is contraindicated in myasthenia gravis. Used with caution in old age and with severe violations of the liver and kidneys.

Release form: 1% solution in ampoules of 1.5 ml (15 mg in 1.5 ml).

Storage: List A.