GI Pharmacology: Intro Flashcards
What is the effect of the SNS on the GI walls, sphincters, and secretions?
Walls: Relaxes via alpha-2, beta-2
Sphincters: Contracts via alpha-1
Secretions: No effect
What is the effect of the PNS on the GI walls, sphincters, and secretions?
Walls: contracts via M-3
Sphincters: Relaxes via M-3
Secretions: Increases via M-3
What is the predominant tone in the GI tract?
Parasympathetic (cholinergic)
What are the effects of cholinergic agonism?
Diarrhea Urination Miosis/muscle weakness Bronchorrhea Bradycardia Emesis Lacrimation Salivation/sweating
What are the component parts of the Enteric nervous system?
The Myenteric plexus (Aurbachs’s): controls the smooth muscle in the GI wall
Meissner’s Plexus: Found in the sub-mucosa, It controls the secretion and neuroimmune aspects of the GI tract
What is the role of Dopamine in the enteric nervous system?
Dopamine is a modulatory transmitter in the ENS
What is the function of Enkephalins in the ENS?
They inhibit Ach release and peristalsis
they MAY stimulate secretion.
What is the function of Serotonin (5-HT) in the ENS?
Serotonin is an important Neurotransmitter/co-transmitter at excitatory neuron-neuron junctions in the ENS.
What are some sub-types of IBS?
D-IBS: diarrhea predominant
C-IBS: Constipation predominant
What are some pharmacologically important causes of IBS?
Excess 5-HT release –> D-IBS
Insufficient release of 5-HT –> C-IBS
What is the underlying cause of IBS?
Alteration of normal microbiota and the bodies reaction to these organisms
What are the predominant symptoms of IBS?
IBS usually involves periods of constipation and diarrhea along with abdominal pain and discomfort.
What are the pharmocologic treatments for IBS (generally speaking)?
Stool softeners: laxatives, lubiprostone
Anti-diarrheal agents: Alosetron
Anti-spasmodics: Dicylomine, Hyoscyamine,ppt oil
TCAs:Amitrytyline, Desipramine, Doxepin
SSRIs: Fluoxetine, Paroxetine, Citalopram
Are Probiotics effective in management of IBS?
Lactobacillus and Bifidobacterium are the most common probiotics used. They improve barrier function, acidify colon, and improve dysmotility. However, they are not highly effective.
What are the effects of Acupuncture, herbal medicine, and psychology on IBS?
Acupuncture and Psychology appear to have no benefit on IBS.
However, Herbal medicines have shown some promise but the evidence is still too weak.
What is IBD?
IBD is an umbrella term for diseases like ulcerative colitis and Crohn’s disease.
Microbe sensing dysfunction (Crohn’s disease)
Disruption of physical barrier (ulcerative colitis)
Immune dysregulation
What cytokine is very important in IBD?
TNF-alpha
What targeted drugs are useful in treating IBD?
Anti-TNF-alpha Mabs Infliximab Adalimumab Gorlimumab Certolizumab pegol
What are the recommendations for using TNF-alpha
MABs for Crohn’s disease?
Used as alternatives to steroids in patients who have failed treatment. Or for maintenance of remission.
What are the recommendations for using Infliximab to treat ulcerative colitis?
Used for patients that are refractory to or unable to take glucocoticoids. Again used in severe cases where treatment has failed.
