Dimetindene Other names: Dimetindene maleate

Dimethidine is an antihistaminic of the alkylamine group. Its action is the result of the capture of histamine H¹ subunits. It has mild anticholinergic and sedative action. When taken by mouth, its action occurs within 30' and lasts for 8-12 hours.

Dimethinden exerts suppressive action on the CNS.

Dimethindene significantly reduces capillary permeability, which is related to immediate hypersensitivity reactions.

As a Η₁ receptor antagonist, dimethindene does not affect the histamine-induced increase in gastric secretion.

Combined with H₂ antihistamines, it suppresses almost all circulatory effects of histamine.

In a histamine challenge dermatitis test, the antihistamine effect of the dimethidine injectable solution occurs after 15-20 minutes. Also in an umbilical and redness test it has been shown that the single-dose 4 mg dose of dimethidine has an intravenous duration of at least 12 hours.

The systemic bioavailability of dimethidine in oral solution is approximately 70%. Maximum serum levels are achieved within 2 hours of oral solution or 1 mg coated tablets. The apparent elimination half-life was approximately 6 hours. At concentrations from 0.09 μg/ml to 2 μg/ml, approximately 90% of dimethidine is associated with plasma proteins.

Following intravenous administration of single doses of 4 mg dimethidine maleate, the area under the plasma concentration curve (AUC) was approximately 140 h.ng.ml ^-1. The apparent half-life of dimethidine in the serum was approximately 6 hours.

At concentrations ranging from 0.09 to 2 mg/ml, about 90% of dimethidine is bound to plasma proteins (in humans).

Metabolic reactions include hydroxylation and methoxylation of the compound. Dimethidine and its metabolites are excreted from bile and urine.

No teratogenic effects have been observed in rats and rabbits. Dimethinden did not affect either the fertility nor the peri- and postnatal development of progeny at doses 250 times higher than the human dose. No mutagenic activity has been observed in various in vitro and in vivo experiments.