Analeptics are medicines that exert a stimulating effect on the respiratory and vasomotor center and some other parts of the central nervous system. Modafinil is one of the most well known analeptics available in pharmacies.
They act almost at all levels of the central nervous system, but each drug is characterized by a certain tropism in relation to its specific structures, as well as the degree of influence on the centers of the medulla oblongata and the ability to provoke convulsions.
Influencing the “vasomotor center”, analeptics increase the peripheral resistance of blood vessels, reduce the deposition of blood, increase the venous return of blood to the heart, which indirectly leads to an increase in its stroke volume. In the conditions of the blockade of vegetative ganglia, the above effects do not arise.
Drugs affect the centers of the medulla oblongata directly, some act reflexively.
Reflexively acting stimulants of respiration are also H-cholinomimetics. All analeptics enhance excitation processes in the central nervous system, facilitating the interneuron transmission of nerve impulses.
Analeptics are used in shallow respiratory depression and blood circulation caused by means depressing the central nervous system (barbiturates, opiates, etc.), bacterial intoxication, as well as in the collapsed state of children that has arisen in hyperthermia and other conditions. Doctors assign them after the child leaves the anesthesia to eliminate hypoventilation of the lungs (which has arisen due to circulatory disorders), thus preventing postoperative complications (atelectasis).
The practical importance of analeptics for the treatment of children is now decreasing, and the indications for their use are narrowing. They are not recommended for deep coma. Increasing the excitability of the central nervous system, analeptics increase the tone of skeletal muscles and, in connection with this, oxygen consumption – there is a “robbery” of the brain and inhibition of neuronal function. In conditions of hypoxia, the children’s preparedness for generalized convulsions rises sharply, and most of these substances are convulsive poisons. When appointing to a child, it should be borne in mind that the range of the doses necessary to stimulate the structures of the medulla oblongata and the doses causing seizures is negligible.
In connection with the above, the analeptics are no longer used in newborns under severe hypoxia.
In toxic doses, analeptics excite the motor centers and cause seizures (from twitching the muscles of the face and individual muscle groups to clonic-tonic convulsions). However, they are followed by the depletion of energy reserves in the central nervous system and the cessation of its function, primarily the respiratory center, which can lead to paralysis of breathing. In these conditions, the appointment of an analeptic is unacceptable, as they can provoke a new fit of seizures and worsen a child’s condition.
When poisoning with analeptics, in addition to cramps, nausea, vomiting, dizziness, often arrhythmic pulse, hyperthermia, in severe cases – pulmonary edema, anuria, and death. When assisting the child, it is necessary to introduce an anticonvulsant urgently to prevent further absorption of the poison (if it has been injected inside) by washing the stomach, prescribing sorbents and saline laxatives, and carrying out detoxification measures (forcing diuresis, maintaining liver detoxication, etc.).