Book contents
- Frontmatter
- Contents
- Contributor
- Preface
- Foreword
- SECTION I Basic principles
- SECTION II Core drugs in anaesthetic practice
- SECTION III Cardiovascular drugs
- SECTION IV Other important drugs
- 17 Central nervous system
- 18 Antiemetics and related drugs
- 19 Drugs acting on the gut
- 20 Intravenous fluids
- 21 Diuretics
- 22 Antimicrobials
- 23 Drugs affecting coagulation
- 24 Drugs used in Diabetes
- 25 Corticosteroids and other hormone preparations
- Index
18 - Antiemetics and related drugs
Published online by Cambridge University Press: 01 June 2010
- Frontmatter
- Contents
- Contributor
- Preface
- Foreword
- SECTION I Basic principles
- SECTION II Core drugs in anaesthetic practice
- SECTION III Cardiovascular drugs
- SECTION IV Other important drugs
- 17 Central nervous system
- 18 Antiemetics and related drugs
- 19 Drugs acting on the gut
- 20 Intravenous fluids
- 21 Diuretics
- 22 Antimicrobials
- 23 Drugs affecting coagulation
- 24 Drugs used in Diabetes
- 25 Corticosteroids and other hormone preparations
- Index
Summary
Nausea and vomiting has many causes including drugs, motion sickness, fear, pregnancy, vestibular disease and migraine. In previous decades anaesthesia was almost synonymous with vomiting, but with the advent of new anaesthetic agents and more aggressive treatment the incidence of vomiting has decreased. However, even the latest agents have failed to eradicate this troublesome symptom encountered in the peri-operative period.
Physiology
The vomiting centre (VC) coordinates vomiting. It has no discrete anatomical site but may be considered as a collection of effector neurones situated in the medulla. This collection projects to the vagus and phrenic nerves and also to the spinal motor neurones supplying the abdominal muscles, which when acting together bring about the vomiting reflex.
The VC has important input from the chemoreceptor trigger zone (CTZ), which lies in the area postrema on the floor of the fourth ventricle but is functionally outside the blood–brain barrier. The CTZ is rich in dopamine (D2) receptors and also serotonin (5-HT) receptors. Acetylcholine (ACh) is important in neural transmission from the vestibular apparatus. Other input is summarized in Figure 18.1.
The treatment of nausea and vomiting is aimed at reducing the afferent supply to the VC. While the administration of antiemetics forms a vital part of treatment, attention should also be given to minimizing the administration of opioids by the use of non-steroidal anti-inflammatory drugs and avoiding unnecessary anticholinesterase administration.
- Type
- Chapter
- Information
- Pharmacology for Anaesthesia and Intensive Care , pp. 282 - 291Publisher: Cambridge University PressPrint publication year: 2008