A 56-year-old woman has nausea due to chemotherapy for breast cancer. Droperidol is effective in reducing nausea because it blocks wof: (A) 5-HT 2 receptors in the CTZ, (B) Glucocoicoid receptors in the vomiting center, (C) Dopamine receptors in the CTZ, (D) ACh receptors in the periphery
Answer is C. NEUROLEPTICS The older neuroleptics(phenothiazines, haloperidol) are potent antiemetics; act by blocking D2 receptors in the CTZ; antagonize apomorphine induced vomiting and have additional antimuscarinic as well as H1 antihistaminic propey. They have broad spectrum antiemetic action effective in: (a) Drug induced and postoperative nausea and vomiting (PONV). (b) Disease induced vomiting: gastroenteritis, uraemia, liver disease, migraine, etc. (c) Malignancy associated and cancer chemotherapy (mildly emetogenic) induced vomiting. (d) Radiation sickness vomiting (less effective). (e) Morning sickness: should not be used except in hyperemesis gravidarum. Ref:- kd tripathi; pg num:-664