What Is a Bronchodilator?

Bronchodilators can relax bronchial smooth muscles, dilate the bronchial tubes, and relieve airflow restriction. They are the main treatments to control the symptoms of COPD. Short-term on-demand application can alleviate symptoms, and long-term regular application can prevent and alleviate symptoms and increase exercise endurance, but cannot improve FEVl (forced expiratory volume) in all patients.

Basic Information

English name

bronchodilator agent

Visiting department

Internal medicine

Bronchodilator classification

There are three main types of bronchodilators currently used to treat COPD: anticholinergic drugs, ₂ receptor agonists, and methylxanthines. The first two can be administered by inhalation, and inhalation is currently recommended because it works quickly and has less systemic adverse reactions. The inhalation device includes a metered aerosol device (MDI) and an atomization inhalation device. In order to improve the effectiveness of inhalation, a mist storage device can also be added between the MDI and the oral cavity. In addition, there are dry powder inhalers (disc inhalers) and inhalation-triggered quantitative inhalation devices (Dubao series), which are easier to grasp and have better inhalation effects. The key to inhalation therapy is that the patient must be proficient in inhalation techniques.

Anticholinergic drugs

The vagus nerve tension of patients with chronic obstructive pulmonary disease is higher, while the basal caliber of the bronchus is determined by the vagus nerve tension. The higher the vagus nerve tension, the narrower the basal caliber. In addition, various stimuli can stimulate the vagus nerve endings and cause bronchospasm reflexively. Anticholinergic drugs can inhibit the vagus nerve, thereby controlling the occurrence of bronchospasm. It is now believed that anticholinergic drugs have a stronger bronchiectasis effect in patients with COPD than ₂ receptor agonists, but the combination of the two has a stronger effect than a single preparation. The currently used anticholinergic inhalant is Aiquale (Ipratropium bromide), which is rarely absorbed from the mucous membranes and has mild systemic adverse reactions. Therefore, it is especially suitable for patients with heart disease and circulatory diseases ; Inhalation takes effect for 5 to 10 minutes, although the effect is slightly slower than ₂ receptor agonist, but it lasts for a long time, reaches a peak in 30 to 90 minutes, and maintains the effect for 6 to 8 hours. Due to the small adverse effects of this drug, which can be inhaled for a long time, no drug resistance and obvious adverse reactions have been found so far. Dosage: Use a volumetric inhaler (MDI) to spray 3 to 4 times a day, 2 sprays at a time, 18 g each, and 2 to 4 sprays if necessary. Long-acting anticholinergic drugs (Tiotropine) have an effect of more than 24 hours. Clinical use of inhalers to absorb drugs has started to be used for the treatment of COPD.

2. ₂ receptor agonist

(1) Short-acting quantitative inhalant vantoline (salbutamol) aerosol and Chuankangsu (terbutaline) aerosol, which takes effect 5 to 6 minutes after inhalation, and reaches a peak in 15 to 30 minutes. 5 hours; each dose is 1-2 sprays (100 g each spray), and no more than 8-12 sprays in 24 hours; it is mainly used to relieve symptoms and be used as appropriate according to the condition, but the long-term application effect may be slightly reduced.

(2) Shiliwen (salmeterol) and Oxydubo (formoterol), long-acting quantitative inhalers , last for more than 12 hours. Formoterol works within 3 to 5 minutes after inhalation, and salmeterol takes 30 minutes to take effect. Therefore, salmeterol is not suitable for treating acute attacks.

(3) Short-acting ₂ receptor agonist tablets Shuchuanling (salbutamol), boricone, and ammonia (clenbuterol).

(4) Long-acting ₂ receptor agonist tablets meprotin (procaterol), quantinine (salbutamol controlled-release tablets), and boriconeni sustained-release tablets.

(5) Common adverse reactions of ₂ receptor agonists , such as hand tremor, palpitation, etc., are obvious at large doses, and generally do not affect continued medication, which can be gradually tolerated with time.

(6) Combined use of anticholinergic drugs and ₂ receptor agonists enhances the efficacy of Copiter aerosols. In the same aerosol, ₂ receptor agonists (salbutamol) and anticholinergic The drug (Ipratropium bromide) is mixed to have a two-pronged effect (Usage: two sprays at a time, four times a day).

3. Methylxanthines (Theophylline)

It can relieve airway smooth muscle spasm, in addition, it can improve heartbeat blood volume, expand the whole body and pulmonary blood vessels, increase water and salt excretion, excite the central nervous system, improve respiratory muscle function and anti-inflammatory effects. However, in general, the other effects of theophylline are not very prominent under the general treatment blood concentration. Oral theophylline sustained-release agents such as Sofomet are currently recommended, 2 times / day. The use of this dose can reduce the number of medications for the convenience of patients, and help maintain the stability of theophylline blood concentration within 24 hours. Adverse reactions include nausea, vomiting, diarrhea, headache, excitement, tremor, and palpitations, which are mostly related to excessive doses and should be reduced if necessary. To prevent overdose, the blood concentration should be measured at the beginning of the medication. Smoking, drinking, application of anticonvulsants and rifampicin can reduce theophylline concentration in the blood. In contrast, the elderly, persistent fever, heart and liver failure, and use of cimetidine, macrolides (erythromycin, etc.), fluoroquinolones (ciprofloxacin, etc.), and oral contraceptives increase blood levels. Drug concentration. Therefore, under the above circumstances, the dose should be adjusted in time under the guidance of a doctor, and the blood drug concentration should be measured if necessary.