Diphenhydramine¿¡ ´ëÇÑ Mechanism_Of_Action Á¤º¸ Diphenhydramine competes with free histamine for binding at HA-receptor sites. This antagonizes the effects of histamine on HA-receptors, leading to a reduction of the negative symptoms brought on by histamine HA-receptor binding.
Pharmacology
Diphenhydramine¿¡ ´ëÇÑ Pharmacology Á¤º¸ Diphenhydramine is an antihistamine of the ethanolamine class. Ethanolamine antihistamines have significant antimuscarinic activity and produce marked sedation in most patients. In addition to the usual allergic symptoms, the drug also treats irritant cough and nausea, vomiting, and vertigo associated with motion sickness. It also is used commonly to treat drug-induced extrapyramidal symptoms as well as to treat mild cases of Parkinson's disease. Rather than preventing the release of histamine, as do cromolyn and nedocromil, diphenhydramine competes with free histamine for binding at HA-receptor sites. Diphenhydramine competitively antagonizes the effects of histamine on HA-receptors in the GI tract, uterus, large blood vessels, and bronchial muscle. Ethanolamine derivatives have greater anticholinergic activity than do other antihistamines, which probably accounts for the antidyskinetic action of diphenhydramine. This anticholinergic action appears to be due to a central antimuscarinic effect, which also may be responsible for its antiemetic effects, although the exact mechanism is unknown.
Diphenhydramine¿¡ ´ëÇÑ Biotransformation Á¤º¸ Hepatic and renal
Toxicity
Diphenhydramine¿¡ ´ëÇÑ Toxicity Á¤º¸ LD50=500 mg/kg (orally in rats). Considerable overdosage can lead to myocardial infarction (heart attack), serious ventricular dysrhythmias, coma and death.
Drug Interactions
Diphenhydramine¿¡ ´ëÇÑ Drug_Interactions Á¤º¸ Atomoxetine The CYP2D6 inhibitor could increases the effect and toxicity of atomoxetineDonepezil Possible antagonism of actionGalantamine Possible antagonism of actionMesoridazine Increased risk of cardiotoxicity and arrhythmiasRivastigmine Possible antagonism of actionThioridazine Increased risk of cardiotoxicity and arrhythmias
Camphor¿¡ ´ëÇÑ Description Á¤º¸ A bicyclic monoterpene ketone found widely in plants, especially cinnamomum camphora. It is used topically as a skin antipruritic and as an anti-infective agent. [PubChem] Diphenhydramine¿¡ ´ëÇÑ Description Á¤º¸ A histamine H1 antagonist used as an antiemetic, antitussive, for dermatoses and pruritus, for hypersensitivity reactions, as a hypnotic, an antiparkinson, and as an ingredient in common cold preparations. It has some undesired antimuscarinic and sedative effects.