Dolasetron (trade name Anzemet) is a serotonin 5-HT3 receptor antagonist used to treat nausea and vomiting following chemotherapy. Its main effect is to reduce the activity of the vagus nerve, which is a nerve that activates the vomiting center in the medulla oblongata. It does not have much antiemetic effect when symptoms are due to motion sickness. This drug does not have any effect on dopamine receptors or muscarinic receptors. Dolasetron breaks down slowly, staying in the body for a long time. One dose is usually administered once or twice daily and lasts 4 to 9 hours. This drug is removed from the body by the liver and kidneys. It was patented in 1986 and approved for medical use in 2002. It is on the World Health Organizations List of Essential Medicines. Medical uses
Chemotherapy-induced nausea and vomiting
5-HT3 receptor antagonists are the primary drugs used to treat and prevent chemotherapy-induced nausea and vomiting. Many times they are given intravenously about 30 minutes before beginning therapy. Post-operative and post-radiation nausea and vomiting
Is a possible therapy for nausea and vomiting due to acute or chronic medical illness or acute gastroenteritis
Unlike most other 5HT3 antagonists, data is lacking for use of dolasetron with aprepitant in chemotherapy-induced nausea and vomiting (CINV). It is also sometimes used as an antiemetic (anti-vomiting medication) in veterinary medicine for dogs and cats. Adverse effects
Dolasetron is a well-tolerated drug with few side effects. Headache, dizziness, and constipation are the most commonly reported side effects associated with its use.
In immunology, the Arthus reaction () is a type of local type III hypersensitivity reaction. Type III hypersensitivity reactions are immune complex-mediated, and involve the deposition of antigen/antibody complexes mainly in the vascular walls, serosa (pleura, pericardium, synovium), and glomeruli. This reaction is usually encountered in experimental settings following the injection of antigens. History
The Arthus reaction was discovered by Nicolas Maurice Arthus in 1903. Arthus repeatedly injected horse serum subcutaneously into rabbits. After four injections, he found that there was edema and that the serum was absorbed slowly. Further injections eventually led to gangrene. Process
The Arthus reaction involves the in situ formation of antigen/antibody complexes after the intradermal injection of an antigen. If the animal/patient was previously sensitized (has circulating antibody), an Arthus reaction occurs. Typical of most mechanisms of the type III hypersensitivity, Arthus manifests as local vasculitis due to deposition of IgG-based immune complexes in dermal blood vessels. Activation of complement primarily results in cleavage of soluble complement proteins forming C5a and C3a, which activate recruitment of PMNs and local mast cell degranulation (requiring the binding of the immune complex onto FcγRIII), resulting in an inflammatory response. Further aggregation of immune complex-related processes induce a local fibrinoid necrosis with ischemia-aggravating thrombosis in the tissue vessel walls. The end result is a localized area of redness and induration that typically lasts a day or so. Arthus reactions have been infrequently reported after vaccinations containing diphtheria and tetanus toxoid.