Antihistamines

Antihistamines block N1-histamine receptors (including bronchi), thereby reducing bronchospasm, permeability of the capillaries and swelling of the bronchi, suppress the excessive response of the bronchi to histamine. They do not solve the problem of bronchial asthma, but, in some cases, especially in the presence of polyvalent allergies, can be used in the complex therapy of atonic bronchial asthma.

[1], [2], [3], [4], [5]

Indications Antihistamines

Antihistamines are usually used in the combination of bronchial asthma with other allergies (urticaria, vasomotor rhinitis, etc.). In severe bronchial asthma and during an attack, the use of antihistamines is ineffective and inappropriate (they cause thickening of phlegm).

[6], [7], [8]

Dosing and administration

2 generations of antihistamines are used.

[9], [10], [11], [12]

Antihistamines of the first generation

Antihistamines of the first generation are classic antihistamines.

• Dimedrol - appoint 0.03-0.05 g orally 2-3 times a day for 10-15 days or as a 1% solution intramuscularly 1 ml 1-2 times a day. Often causes drowsiness.
• Fenkarol - is released in tablets at 0.025 g, take 1 tablet 3-4 times a day after meals for 10-20 days. In contrast to dimedrol, the preparation not only blocks the H1-histamine receptors, but also reduces the histamine content in the tissues (since it activates the diamino oxidase, an enzyme that destroys histamine). Has no pronounced sedative effect, does not cause drowsiness.
• Pipolphene (diprazine) - is released in tablets of 0.025 g, appoint orally 1 tablet 2-3 times a day after meals or intramuscularly 1-2 ml of 2.5% solution. The drug has a rather pronounced sedative effect.
• Diazolinum - is issued in tablets by 0.05 and 0.1 g, is given orally 1 tablet 3 times a day, as a rule, does not cause sedative and hypnotic effects.
• Dimebon - is manufactured in tablets of 0.01 g, applied orally 1 tablet 3 times a day (regardless of food intake). May have a sedative effect. Along with protivogistaminnym action causes a partial antiserotoninovy effect.
• Suprastinum - is issued in tablets on 0.025 g and in ampoules of 1 ml of 2% solution. Assigned inside to 0.025 g 3 times a day during meals, you can enter intramuscularly 1-2 ml of 2% solution. The drug has antihistaminic and peripheral anticholinergic activity.
• Tavegil - is issued in tablets of 1 mg, ampoules of 2 ml of 0.1% solution. Close to dimedrol, but more active and lasts longer (8-12 hours after a single dose). It is prescribed for 1 mg in the morning and in the evening, the daily dose can be increased to 3-4 tablets. Causes a mild sedative effect.

Disadvantages of antihistamines I generation:

• have a sedative and hypnotic effect due to good penetration through the blood-brain barrier and blockade of the central histamine receptors;
• violate the concentration of attention and cause ataxia (contraindicated to patients, working drivers, operators, dispatchers, etc.);
• show holinoliticheskoe action that is expressed in dryness in a mouth, a tachycardia, a delay of urine, locks, infringement of accommodation;
• increase the viscosity of sputum in patients with bronchial asthma, which exacerbates bronchial obstruction;
• have an antihypertensive effect;
• cause the development of habituation with prolonged use, in connection with which it is advisable to change the drugs every two weeks.

[13], [14], [15], [16], [17]

Antihistamines of the second generation

Antihistamines of the second generation have the following advantages in comparison with the preparations of the first generation:

• do not have sedative and hypnotic effects, since they are lipophobic and poorly penetrate the blood-brain barrier;
• selectively block H1-histamine receptors, do not have cholinolytic and adrenolytic activity;
• quickly show a therapeutic effect (after 30-60 minutes) due to good absorption from the gastrointestinal tract;
• form strong bonds with H1-histamine receptors and are slowly excreted from the body, so they have a long-lasting effect and can be applied 1-2 times a day (except for acrivastine);
• do not become addictive even with prolonged use;
• reduce the release of mediators from mast cells and bazofilov along with the blockade of H1-histamine receptors and to a certain extent may have an anti-inflammatory effect.

1. Terfenadine (terfen, triludane, teldan) - is applied to 0.06 g 2 times or 0.12 g once a day.
2. Astemizole (gismanal) - is prescribed for 10 mg once a day.
3. Terfenadine and astemizole can cause heart rhythm disturbances, so they are not used for concomitant diseases of the cardiovascular system.
4. Loratidine (klaritin) - is prescribed by 0.01 g (1 tablet) once a day.
5. Acryvastin (semprex) - is used in capsules, 1 capsule 2-3 times a day.
6. Cetirizine (zirtek) - applied 10 mg once a day (during dinner).

[18], [19], [20], [21], [22]