Drugs for Bowl Disorders and other GI Conditions碗和其他胃肠疾患的药物和条件.pptxVIP

Drugs for Bowel Disorders and other GI Conditions Chapters 40 41 1 Nausea Definitions of nausea on the Web: the state that precedes vomiting disgust so strong it makes you feel sick/perl/webwn comes from the Greek word for ship, naus, which currently can be defined as a queasy or upset stomach./educate/neptune/lesson/language/origin.htm 2 Emesis (Vomit) Emesis : the reflex act of ejecting the contents of the stomach through the mouthwordnetweb.princeton.ed From the Indo-European root wem- (to vomit), the source of the words such as emetic and wamble (to feel nauseated). /script/main/art.asp?articlekey=6005 The body’s protective mechanism to eject harmful/toxic materials or substances Adams, P., Holland, L., Urban, C., 2011 3 Pathophysiology Vomit Center located in Medulla of Brain. Receives sensory input from G.I., inner ear Chemoreceptor Trigger Zone (CTZ) in cerebral cortex. Noxious stimuli (dizziness, spoiled food/infection, drugs/anesthesia, pain or trauma, pregnancy) signals the Vomit Center which in turn stimulates the stomach resulting in nausea /or vomiting. 4 Antiemetics 1st Group: Serotonin (5-HT3) Receptor Antagonist Odansetron (Zofran) 4 mg PO/IV Q 4-8 hrs PRN n/v Action: Blocks Serotonin Receptors in CTZ and Vagal Nerve terminals in G.I. Tract. Indications: Post General Anesthesia Chemotherapy Adverse Effects H/A, drowsiness, fatigue, constipation, diarrhea Serious: dysrhythmias, extrapyramidal symptoms (EPS) Pearson Education, Inc. 2008, 2011. Wilson B., Shannon, M., Shields, K., 2009 5 Anti-Emetics 2nd Group: Phenothiazines (primary use as an antipsychotic) Action: affects CTZ to inhibit n/v. Larger doses inhibit signals to Vomit Center by blocking dopamine receptors. Prochlorperazine (Compazine) (prototype drug) 5-10 mg PO TID or QID: 2.5-10 mg IV (no more than 5 mg/min), serious adverse effect includes extrapyramidal symptoms (EPS): akathisia or restlessness, dystonia, parkinsonism. Metoclopramide (Reglan) (action unknown) 10mg P