A cough is a major symptom of respiratory diseases. A cough is a protective reflex that promotes the discharge of sputum and foreign matter from the respiratory tract and keeps the airway clean and fluent.
A cough is a protective reflex. A mild cough can help remove sputum and foreign body in the trachea, and it will naturally relieve. Generally, no cough medicine is needed. A strong and frequent cough, especially dry cough, can affect rest and sleep. Even if the disease is aggravated and causes other complications, it is necessary to add a cough and expectorant drugs while treating the cause.
The use of antitussives is currently limited, and many antitussives lack the exact antitussive effect or have adverse reactions that are difficult for patients to tolerate.
Fortunately, with the in-depth study of the cough reflex mechanism, scientists have discovered some drugs with new mechanisms of action.
Selective opioid and opioid receptor agonists, capsaicin receptor (VR), tachykinin receptor (TK) antagonists, neurokinin receptor antagonists, prostaglandin synthesis inhibitors, potassium channel openers, Cl ion channel modulators, 5-TH receptor antagonists, GABA-B receptor agonists, etc. are all hot spots in research. These studies are expected to yield antitussives with more potent and less adverse reactions.
Drug category and dosage form
The central antitussives use 41%, the peripheral antitussives are 59%; the single dosage form is 45%, the compound dosage form is 55%, the difference is not very large, but the central antitussives are non-dependent. Sex antitussives.
It may be related to the type of hospital medicines and the medication habits of clinicians. The selection of antitussive drugs requires the physician to strictly control the characteristics of the drug, pay attention to indications, contraindications, incompatibility, and adverse reactions.
In particular, it is necessary to grasp the specific drug composition of the compound preparation to avoid mistakes in medication and repeated use of drugs. At the same time, we must learn to use the cough score and visual analog scoring system to evaluate the severity of a cough in patients.
Commonly used drugs
Central antitussives directly inhibit the cough center of the medulla oblongata and produce an antitussive effect, which is divided into dependent and non-dependent antitussives.
a> Dependent antitussive:
Codeine: directly inhibits the medullary cough center, has a strong and rapid antitussive effect, and also has analgesic and sedative effects. It can be used for severe dry cough and an irritating cough caused by various causes, especially dry cough with chest pain.
B> Independent antitussives:
Dextromethorphan: The effect is similar to that of codeine. The therapeutic dose has no inhibitory effect on the respiratory center, no analgesic effect, and no addiction. It is the most widely used clinically and is suitable for coughing in colds, acute or chronic bronchitis, bronchial asthma, pharyngitis, tuberculosis, and other upper respiratory tract infections.
It has a selective inhibitory effect on the cough center and has a mild atropine-like effect and local anesthetic effect. The high dose has an antispasmodic effect on bronchial smooth muscle and has both central and peripheral antitussive effects. The antitussive effect is about 1/3 of codeine, and there is no addiction. It is used clinically for a long time. It is used for intestines caused by upper respiratory tract infection, such as a dry cough and whooping cough.
It has an antitussive effect by inhibiting any of the receptors, afferent nerves, efferent nerves and effectors in the cough emission arc.
a Nading: Also known as the “codeine” in the periphery. The isoflavonoid alkaloid contained in opioids produces a peripheral antitussive effect by inhibiting lung stretch reflex and relieving bronchial smooth muscle spasm. It has special therapeutic value for various allergic cough, spastic cough, severe and paroxysmal cough, and it can also inhibit inflammation caused by respiratory secretions.
b benproperine: a non-narcotic antitussive, which acts 2 to 4 times more than codeine, inhibits peripheral afferent nerves, and inhibits cough center. It is used to treat a cough caused by acute and chronic bronchitis and various stimuli.
It is the first choice for a severe cough. Note: After taking the medicine, there may be a transient mouth and pharyngeal numbness. In addition, there are still adverse reactions such as fatigue, dizziness, and upper abdominal discomfort. If a rash occurs during the medication, the drug should be discontinued.
A cough with many phlegms should be combined with expectorants such as ammonium chloride, bromine, acetylcysteine, etc., in order to facilitate the discharge of sputum and antitussive effect. There are also some compound preparations containing antitussive, expectorant, antihistamine, and other drugs, which have many clinical applications.
a compound methoxyphenamine: capsule contains methoxyphenamine hydrochloride, narcotine, aminophylline, chlorpheniramine maleate. It can alleviate a cough caused by inflammation of the throat and bronchus, relieve a cough during asthma attacks, and facilitate drainage.
Note: Patients with heart disease, high blood pressure or advanced age, glaucoma, hyperthyroidism, dysuria, and those undergoing treatment should be cautious.
b can be more syrup: has obvious antitussive and antitussive effect. Codeine has a certain addiction to long-term or high-dose applications. Guarin is a stimulating peony that can dilute sputum and is easy to cough up.
Principle of use
A cough can be caused by a variety of reasons, the key to medication is the cause of treatment. Some coughs are caused by bronchial asthma, and antiasthmatic treatment is effective; some are caused by esophageal reflux and are effective with gastric motility drugs and antacids.
Symptomatic treatment is needed when the cause of the disease cannot be immediately effective. For patients with irritating dry cough, it is preferred to use benproperine or pentavirin. Patients with a severe cough should choose benproperine and dextromethorphan. It is advisable to use benproperine for a cough during the day and dextromethorphan for a cough at night.
A cough with more sputum should be based on sputum. It is not advisable to use antitussives alone. It should be combined with sputum to facilitate the discharge and antitussive effect of sputum. A cough with many phlegms should be combined with expectorants such as ammonium chloride, bromine, acetylcysteine, etc., in order to facilitate the discharge of sputum and antitussive effect.
Pay attention to adverse reactions
Dextromethorphan can cause drowsiness, do not use when driving a car or working at heights, and women with a history of mental illness within 3 months of pregnancy are prohibited; glaucoma, cardiac insufficiency with pulmonary congestion should be used with caution. Central antitussives are only suitable for severe dry cough and should be avoided in old age, pregnant women and children.