June 7, 2021 0 Comments

Spasmolytics (from Greek spasmos – cramp, spasm, and lyticos – releasing, relieving) are drugs that weaken or completely eliminate spasms of the smooth muscles of internal organs and blood vessels. Among them:

Smooth (as opposed to transverse striated) musculature, or muscle tissue, is widely found in the h

uman body. It forms the muscular membranes of hollow internal organs, walls of blood and lymphatic vessels, is present in skin, glands, sense organs (including the structure of eyes). With its help, in particular, the contractile activity of the digestive tract is carried out, and the tone of blood vessels is maintained. Functionally, this muscle type is referred to as involuntary musculature, i.e. its activity is controlled mainly by the vegetative nervous system. This is the main difference between it and the voluntary musculature, which consists of striated muscles that form muscles of the head, neck, trunk, and limbs. Arbitrary muscles are under the control of the central nervous system and are responsible for movement, maintaining balance, maintaining posture. Thanks to it a person can also chew, swallow, and speak.

Antispasmodics relax the smooth muscles of internal organs and reduce vascular tone. Since the activity of these muscles is controlled by the autonomic nervous system, it is easy to assume that many drugs that affect the conduction of impulses in this system will have the properties of antispasmodics. Such antispasmodics are referred to neurotropic drugs. We have already discussed their properties in detail in Chapter 2.2 “Agents affecting the autonomic nervous system”. We can only emphasize once again that many cholinolytics, adrenomimetics and adrenoblockers cause relaxation of smooth muscles, which determines their vasodilator, bronchodilator, analgesic and other properties. This effect is associated with a decrease in the vasoconstrictor influence of the sympathetic department of the autonomic nervous system and is realized through the corresponding receptors of nerve cells.

Myotropic antispasmodics, unlike neurotropic ones, have a direct rather than indirect effect on smooth muscle cells, changing the ionic balance in the cell membrane. As a result, complex biochemical reactions are triggered, leading to a decrease in the contractile activity of the cells. The muscle relaxes, and, therefore, the tone of the blood vessel decreases, the spasm is relieved, for example, the bile ducts, ureters expand.

The main representatives of myotropic antispasmodics are drotaverine (better known as the drug No-shpa), papaverine, benciclane, bendazole and others. They are used in the treatment of cardiovascular diseases, diseases of the gastrointestinal tract and other conditions when it is necessary to get a vasodilator effect or to relieve spasm of the smooth muscles of internal organs (hypertonicity, various colics, headache and so on).