Vomiting congeners

Benzodiazepines and their congeners may help prevent central cortical-induced vomiting. A prominent side effect is drowsiness. They are frequently used in combination with other antiemetics for treating chemotherapy-related nausea and vomiting. Discussion of these agents is found in Chapter 30. 

Drugs such as pilocarpine and the choline esters cause predictable signs of muscarinic excess when given in overdosage. These effects include nausea, vomiting, diarrhea, salivation, sweating, cutaneous vasodilation, and bronchial constriction. The effects are all blocked competitively by atropine and its congeners. 

A transdermal delivery system has been developed for prevention of motion sickness and vomiting, using an adhesive patch for postauricular application the drug is released at a uniform rate for 72 hours. The adverse effects of this formulation are qualitatively typical of those reported for the oral and parenteral formulations of hyoscine and its congeners, although comparative studies suggest that the incidence is reduced with transdermal administration. Nevertheless, adverse effects involving the central nervous system, vision, bladder, and skin have been described, as have withdrawal symptoms after the patch is removed. 

Ondansetron and its congeners are extremely useful in the control of vomiting associated with cancer chemotherapy and postoperative vomiting. Alosetron, another 5-HTj antagonist, was used in irritable bowel syndrome in women but has been withdrawn. 

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