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Diphenhydramine
- indication:For the treatment of symptoms associated with Vertigo/Meniere's disease, nausea and vomiting, motion sickness and insect bite.
- pharmacologypharmacology:
- mechanism: 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.
- toxicity: LD<sub>50</sub>=500 mg/kg (orally in rats). Considerable overdosage can lead to myocardial infarction (heart attack), serious ventricular dysrhythmias, coma and death.
- absorprion: Quickly absorbed with maximum activity occurring in approximately one hour.
- halflife: 1-4 hours
- roouteelimination: Little, if any, is excreted unchanged in the urine; most appears as the degradation products of metabolic transformation in the liver, which are almost completely excreted within 24 hours.
- volumedistribution:
- clearance: