CHAPTER 13. DRUGS AFFECTING THE RESPIRATORY SYSTEM

In this Chapter:

13.1. Respiration stimulants

13.2. Antitussive drugs

13.3. Expectorants

13.4. Drugs used for the treatment of bronchospasm

13.5. Drugs used in acute respiratory failure

13.1. RESPIRATION STIMULANTS

According to the direction of their action, respiratory stimulants are subdivided into the following groups (Fig. 13.1):

• Drugs affecting the respiratory center directly

- Bemegride

- Caffeine

- Aethimizolum

• Reflex respiratory stimulants

- Cytiton

- Lobeline

• Drugs of the mixed type of action

- Nikethamide (cordiaminum)

- Carbon dioxide

Drugs that stimulate the respiratory center directly are caffeine (that is known to be a psychostimulating agent and an analeptic [See Chapter 11.6]), bemegride (analeptic) and aethimizolum¹. The last agent has a special place among centrally acting respiratory stimulants. It activates both the subcortical structures of the brain and medulla oblongata. Aethimizolum differs from typical analeptics because it suppresses the cerebral cortex, which is why it is used not only as a respiratory stimulant, but also as a sedative to treat anxiety. This drug can be taken orally or parenterally.

Reflex respiratory stimulants include N-cholinomimetics such as cytiton and lobeline (see Chapter 3.4). The mechanism

¹ It is a derivative of imidazole dicarboxylic acid (see structure).

Fig. 13.1. The main directions of action of the drugs affecting the functions of the respiratory organs.

of their action is the activation of N-cholinoceptors of the carotid body from where afferent impulses run to the medulla oblongata and increase the activity of the respiration center. The above mentioned cholinomimetics have a short-term effect (minutes). They are used for intravenous injections only.