antiasthmatic
First of all, adrenergic drugs
[Mechanism of antiasthmatic action]
(1) Stimulate β2 receptor of bronchial smooth muscle → activate adenylate cyclase → cell camp↑→ bronchiectasis.
(2) Stimulate the β receptor of mast cells → intracellular camp↑→ inhibit the release of its active substances.
(3) Adrenaline can stimulate vascular α receptor of bronchial smooth muscle mucosa → mucosal congestion and edema ↓
[Common drugs]
1, non-selective β -adrenergic drugs: epinephrine, ephedrine, isoproterenol Source: Examination University.
2. Selective β _ 2 receptor agonist: Comparison of antiasthmatic effects of salbutamol and clenbuterol adrenergic drugs. Maintenance time of antiasthmatic mechanism (h) The main adverse reactions of administration route are adrenergic α, β 1, β _ 2 receptor strong, rapid 1 ~ 2 subcutaneous and intravenous palpitation and pressor. Myopia, headache and restlessness during acute asthma attack can be promoted by intramuscular injection of ephedrine for 3 ~ 6 times, which can stimulate α and β receptors weakly, slowly and continuously, prevent subcutaneous insomnia, palpitation and mild symptoms, and prevent pressor and rapid tolerance. Isoproterenol can stimulate β 1 and β2 receptors of1sublingual tablets strongly and quickly during asthma attack. Acute asthma tolerance, excessive ventricular fibrillation attack, salbutamol selectively excites β2 receptor for 4 ~ 6 days, clenbuterol selectively excites β2 receptor 100 times as much as salbutamol acute attack, and 4 ~ 62 ~ 6 times of oral atomization inhalation of finger tremor can prevent the attack.
Second, the source of theophylline: the exam is big.
Aminophylline (aminophylline):
[Function and Use]
(1) Anti-asthma effect: inhibit phosphodiesterase → increase camp → relax smooth muscle, and reduce the release of allergic mediators. It has synergistic effect with β receptor agonist, but it is still effective if it is ineffective against the latter. Severe asthma or current situation can be treated by intramuscular injection or intravenous drip, and mild or preventive can be treated by oral administration.
(2) Cardiotonic diuretic effect: used for cardiorenal edema.
[Adverse reaction]
(1) local stimulation: oral administration can cause gastrointestinal reaction; Intramuscular injection can cause redness and pain.
(2) Arrhythmia, blood pressure drop and convulsion: it is easy to happen when the intravenous injection speed is fast or the dose is too large, and children are more likely to cause convulsions.
Bile theophylline and dihydroxypropyl theophylline (Chuanding): Similar to aminophylline, but less irritating to gastrointestinal tract, and Chuanding is not as exciting to the heart as aminophylline.
Third, anticholinergic drugs:
It plays an antiasthmatic role by selectively blocking the M receptor on bronchial smooth muscle.
Isopropyl atropine: It has less influence on heart rate and gland secretion than atropine, and has no central function. When inhaled, it takes effect quickly and lasts for a long time, and its intensity is not as good as that of adrenergic drugs. Used for asthmatic chronic bronchitis and bronchial asthma.
Fourth, anti-allergic drugs:
Sodium cromoglycate:
【 Mechanism 】 Stabilize mast cell membrane and inhibit mast cell degranulation, thus inhibiting the release of allergic active substances.
[Functional features]
(1) has a slow onset and is ineffective for asthma;
(2) It is difficult to be absorbed orally, so powder mist is inhaled for administration. Source: Examination University
[Purpose] It is suitable for preventing exogenous bronchial asthma, allergic rhinitis and food allergy.
Megestrol acetate (ketotifen):
It can be taken orally, inhibit the release of allergic mediators, block h 1 receptor and prevent asthma, and its curative effect is better than cromoglycine. Used for exogenous asthma, especially for children.