Paracetamol, loratadine and cetirizine hydrochloride all belong to the antihistamine class of anti-allergy drugs. Their differences are:

1, according to the pharmacological classification: paracetamol belongs to the first generation of antihistamines, is the first generation of h1 receptor antagonists; and loratadine and cetirizine hydrochloride are the second generation of antihistamines, is the second generation of h1 receptor antagonists.

2, from the efficacy: the first generation of antihistamines paracetamol due to a strong central nervous system inhibition, and the second generation of antihistamines loratadine and cetirizine hydrochloride have no sedative effect or sedative effect is slight. And the first generation of antihistamines absorption is relatively slow, slow onset of action, the maintenance of efficacy time is short; the second generation of antihistamines absorption is fast, the maintenance of efficacy time is long.

3, loratadine and cetirizine are the most widely used second-generation anti-allergy drugs, but the role is also slightly different. Loratadine is used to relieve symptoms associated with allergic rhinitis, such as sneezing, runny nose, itchy nose, nasal congestion, etc.; also used to relieve chronic urticaria, itchy skin disease and other allergic dermatologic signs or symptoms. However, loratadine should not be used in children under 2 years of age because of definite drug interactions and cardiotoxic side effects.

Cetirizine is primarily used for seasonal or perennial allergic rhinitis, hives and itchy skin caused by allergens, and allergic conjunctivitis. Studies in recent years have also found that cetirizine is also effective against allergic asthma.

Antihistamines can be divided into first-generation antihistamines, second-generation antihistamines and third-generation antihistamines. And paracetamol, loratadine, cetirizine hydrochloride all belong to the antihistamines, their differences are:

1, paracetamol: also known as chlorpheniramine, as a first-generation antihistamine, can fight against allergic reaction (histamine) caused by the dilation of the capillaries, reduce the permeability of capillaries, alleviate the contraction of bronchial smooth muscle due to wheeze, paracetamol antihistamine effect is more persistent, but its central nervous activity, poor receptor specificity. The antihistamine effect of paracetamol is longer lasting, but its central nervous system activity, poor receptor specificity, can lead to obvious sedation and anticholinergic effect, making patients drowsy or difficult to concentrate on the ability to work.

2, loratadine: also known as bacitracin, karetin. It is the second generation antihistamine commonly used in China at present. The incidence of central nervous system inhibition side effects is very low, greatly reducing the first generation of antihistamines produced by drowsiness or difficulty concentrating at work and other adverse reactions. Anticholinergic effects are also mild, with occasional dizziness, headache, fatigue and dry mouth, and mild digestive side effects. It is used to relieve symptoms related to allergic rhinitis and symptoms of chronic urticaria and other allergic skin conditions.

3, cetirizine hydrochloride: is another second-generation antihistamine currently in use in China. Cetirizine is mainly used for seasonal or perennial allergic rhinitis, urticaria and skin itching caused by allergens, allergic conjunctivitis. In recent years, studies have found that cetirizine also has a role in the prevention and control of allergic asthma and is included in the treatment of allergic asthma.

The first-generation antihistamines are now used less frequently because of their side effects. And loratadine and cetirizine, as the most widely used anti-allergy drugs, are both long-acting formulations that are easy to take. However, loratadine should not be used in children under 2 years of age because of definite drug interactions and cardiotoxic side effects.

Expanded:

Anti-allergic drugs, according to the different mechanisms of action, can be divided into the following categories: antihistamines, allergic reaction mediator blockers, hormonal drugs, immunomodulatory drugs and so on.

And antihistamines: antihistamines can be divided into first-generation, second-generation and third-generation antihistamines. Among them, benadryl, paracetamol and ipratropium are first-generation antihistamines. Second-generation antihistamines include loratadine, cetirizine, and ibastine. The third-generation antihistamines are represented by desloratadine, fexofenadine, levocetirizine and so on.

1, paracetamol: also known as chlorpheniramine, as the first generation of antihistamines, can fight against allergic reactions (histamine) caused by capillary dilatation, reduce the permeability of capillaries, relieve bronchial smooth muscle contraction caused by wheezing, paracetamol antihistamine effect is more durable, but its central nervous activity, receptor specificity is poor, can lead to obvious sedation and anticholinergic effect, make the patient drowsy or working ability to concentrate. The ability to concentrate is difficult.

2, loratadine: also known as bacitracin, karetin. It is the second generation antihistamine commonly used in China. The incidence of central nervous system inhibition side effects is very low, greatly reducing the first generation of antihistamines produced by drowsiness or difficulty concentrating at work and other adverse reactions. Anticholinergic effects are also mild, with occasional dizziness, headache, fatigue and dry mouth, and mild digestive side effects. It is used to relieve symptoms associated with allergic rhinitis and symptoms of chronic urticaria and other allergic skin conditions.

3, cetirizine hydrochloride: is another second-generation antihistamine currently in use in China. Cetirizine is mainly used for seasonal and perennial allergic rhinitis, rhinoconjunctivitis, urticaria, allergies caused by medicines, food and insect bites. A side effect of cetirizine that was found to be more common than placebo in clinical studies was dry mouth. At effective doses, it does not readily cross the blood-brain barrier and does not affect the central nervous system as a side effect.

Baidu Encyclopedia - Anti-Allergy Drugs

Baidu Encyclopedia - Antihistamines

Baidu Encyclopedia - Cetirizine Hydrochloride