Pharmacology of laxatives and emetics Flashcards
Know about abnormal bowel activity (IBS, IBD)
and treatments
Irritable Bowel Syndrome (IBS): IBS is a chronic functional disorder that affects the large intestine, causing symptoms such as abdominal pain, bloating, constipation, and diarrhea. The exact cause of IBS is not fully understood, but it may involve factors such as changes in gut motility, sensitivity, or the gut microbiome. Treatment for IBS may include dietary changes, stress management, probiotics, and medications such as antispasmodics, laxatives, or antidepressants.
Inflammatory Bowel Disease (IBD): IBD is a chronic inflammatory condition that affects the digestive tract, including Crohn’s disease and ulcerative colitis. Symptoms may include abdominal pain, diarrhea, weight loss, and fatigue. Treatment for IBD aims to reduce inflammation, relieve symptoms, prevent complications, and improve quality of life. Treatment options may include medications such as anti-inflammatory drugs, immunomodulators, biologic agents, Janus kinase (JAK) inhibitors, antibiotics, surgery, and nutritional therapy.
Understand how PNS and CNS mechanisms result
in the vomiting reflex
Stimuli from the gastrointestinal tract or inner ear are detected by sensory receptors and transmitted through the PNS to the vomiting center in the brainstem.
The vomiting center in the brainstem receives these signals and sends out a series of coordinated motor responses through the PNS. This includes activation of the diaphragm and abdominal muscles, which increase intra-abdominal pressure, and relaxation of the lower esophageal sphincter, which allows the stomach contents to be expelled.
The CNS also plays a role in triggering the vomiting reflex. The CTZ in the brainstem can be activated by various stimuli, such as drugs or toxins in the bloodstream, and can send signals to the vomiting center to initiate the vomiting reflex.
The CNS also plays a role in the emetic response. The emetic response is a complex reflex that involves the coordination of several neural and hormonal pathways. It is triggered by the activation of the CTZ and involves the release of various neurotransmitters, such as serotonin, dopamine, and substance P, which act on receptors in the vomiting center to initiate vomiting
Know about the range of drugs that are used to
cause or inhibit emesis
Serotonin (5-HT3) receptor antagonists, such as ondansetron and granisetron, which block the action of serotonin in the gut and central nervous system (CNS).
Dopamine receptor antagonists, such as metoclopramide and prochlorperazine, which block dopamine receptors in the CNS.
Cannabinoids, such as dronabinol and nabilone, which act on the endocannabinoid system in the brain.
Glucocorticoids, such as dexamethasone, which have anti-inflammatory and immunosuppressive effects and can also reduce nausea and vomiting.
Benzodiazepines, such as lorazepam, which can help to reduce anxiety and other symptoms that may contribute to nausea and vomiting.
