Mode of action
The active ingredient of clemastine belongs to the group of antihistamines. The active substance represents an antagonist (opponent or also inhibitor) at the histamine receptor H1. Histamine is a messenger substance in the human body, which shows its effect for example as a tissue hormone or as a transmitter in the nervous system.
Histamine plays an important and decisive role in allergic reactions. Histamine causes tissue swelling in the course of inflammatory reactions. Histamine is stored in the body in various cells.
It is found in cells of the bronchi or the gastrointestinal tract and also in the mucous membrane. High concentrations of histamine are also found in various blood cells such as mast cells or so-called basophilic granulocytes, which are a subgroup of white blood cells. Allergic reactions of the immediate type result in a massive release of histamine from the mast cells.
The release of histamine has a variety of effects in the body, such as vasodilatation with an increased risk of edema in the skin and mucous membranes. The vasodilatation can also lead to a drop in blood pressure. Itching, redness and swelling are typical reactions of the skin to histamine. These symptoms can therefore be reduced by inhibiting the H1-histamine receptors, since the effect of histamine cannot be mediated.
Metabolism
The active ingredient in Tavegil® can be almost completely absorbed by the body. The blocking effect of histamine inhibitors (antihistaminergic effect) reaches its peak after about 5-7 hours. Tavegil®, like many other drugs, is metabolized in the liver. Once metabolized, it is then excreted via the kidneys and urine.
Contraindications
You should not take Tavegil® if you are hypersensitive to the active ingredient clemastine. You should also avoid other antiallergics with a chemically similar active ingredient.Patients with elevated intraocular pressure due to a flow disorder (so-called narrow-angle glaucoma) or symptomatic enlargement of the prostate should also not take Tavegil®. There are insufficient data for use in patients with liver and kidney function impairment. It is therefore advisable not to take Tavegil® tablets/syrup. Patients with existing heart disease, electrolyte imbalances in the blood or congenital so-called long QT syndrome should be particularly careful and possibly arrange for ECG checks, as taking Tavegil® may lead to an increased risk of cardiac arrhythmia.
