Information about Telotristat
Telotristat is an oral, small molecule inhibitor of tryptophan hydroxylase that is used in the treatment of symptoms of carcinoid syndrome.
Liver safety of Telotristat
Telotristat is associated with modest rate of minor serum enzyme elevations during therapy but has not been linked to cases of clinically apparent liver injury.
Mechanism of action of Telotristat
Telotristat (tel oh' tri stat) is an oral small molecule inhibitor of tryptophan hydroxylase, an enzyme that is responsible for the rate-limiting step in serotonin (5-hydroxtryptamine) synthesis. Serotonin is a neuroactive signaling molecule that is produced in excess by some neuroendocrine tumors and causes the symptoms of carcinoid syndrome (flushing, diarrhea, abdominal pain and heart valvular complications). Carcinoid syndrome is typically treated with somatostatin analogues that inhibit the growth of neuroendocrine tumors. However, treatment with somatostatin analogues (such as octreotide, lanreotide and pasireotide) does not always control symptoms of carcinoid syndrome, particularly the diarrhea and abdominal discomfort. Telotristat does not decrease the neuroendocrine tumor size or growth but lowers the peripheral synthesis of serotonin which leads to decreased plasma levels. In several small, prelicensure clinical trials, telotristat therapy was associated with a decrease in diarrhea in at least half of treated patients with carcinoid syndrome, with residual diarrheal symptoms despite stable doses of somatostatin analogues.
FDA approval information for Telotristat
Telotristat was approved for this indication in the United States in 2017 and is available in tablets of 250 mg under the brand name Xermelo.
Dosage and administration for Telotristat
The recommended adult dosage is 250 mg three times daily.
Side effects of Telotristat
Common adverse events include nausea, constipation, flatulence, anorexia, and abdominal pain. Rare, but potentially severe adverse events include severe constipation and depression.
Antidiarrheal agents include bulk forming agents, hydroscopic agents, bile acid resins, bismuth, inhibitors of intestinal motility, non-absorbed antibiotics and hormones. Bulk forming agents include methylcellulose; hydroscopic agents include pectin and kaolin; bile acid resins are cholestyramine, colestipol and colesevalam; inhibitors of intestinal motility include opioids such as diphenoxylate and loperamide. Antibiotics include rifamycin and rifaximin which are non-absorbed and are used for travelers' diarrhea. Hormones with antidiarrheal activity include octretide and somatostatin. Most antidiarrheal agents are active locally in the small intestine and colon and are largely not absorbed. Some, however, have been implicated in rare causes of liver injury (senna, cascara, cholestyramine). Telotristat is a relatively new agent that inhibits the synthesis of serotonin and is used specifically for the diarrhea of carcinoid syndrome.
Antiemetics are a diverse group of medications that act at different points in the pathways that regulate nausea and vomiting. These include antihistamines, anticholinergic agents, phenothiazines, serotonin type 3 receptor blockers, centrally acting benzamides, cannabinoid receptor agonists, substance P antagonists and miscellaneous.
Cannabinoid Receptor Agonists
- Dronabinol, Nabilone, Tetrahydrocannabinol
- Phenothiazines [See Antipsychotic Agents]
- Chlorpromazine, Prochlorperazine
Substance P/Neurokinin 1 Receptor Antagonists
Acid peptic disease/antiulcer agents that include antacids, the histamine type 2 receptor blockers (H2 blockers), and the proton pump inhibitors (PPIs). These agents are some of the most commonly taken medications and are very well tolerated, most being available both by prescription and over-the-counter. While many of these drugs are approved for use in duodenal and gastric ulcer disease, their major use is for acid reflux and indigestion.
Cathartics, laxatives or agents for constipation include bulk forming agents, osmotic agents, stool wetting agents, nonspecific stimulants, prokinetic agents and agents that increase fluid secretion. Many of these therapies are not systemically absorbed and none are considered particularly hepatotoxic. Naldemedine and naloxegol are opioid antagonists and are used to treat the constipation associated with opioid use.
- Cascara Sagrada
- Castor Oil
- Fiber, Bran
- Magnesium Sulfate
- Naldemedine (Opioid Antagonist)
- Naloxegol (Opioid Antagonist)
- Plecanatide (for Chronic Idiopathic Constipation)
- Prucalopride (for Chronic Idiopathic Constipation)
Inflammatory bowel disease encompasses several disorders, most commonly ulcerative colitis and Crohn colitis. Agents can be classified as 5-aminosalicyclic acid (5-ASA) based agents, immunosuppressive drugs, antitumor necrosis factor agents, corticosteroids, antibiotics and miscellaneous.
5-Aminosalicyclic Acid (5-ASA) Derivatives
Tumor Necrosis Factor Antagonists
Irritable Bowel Syndrome Agents Antimuscarinics/Antispasmodics [See Anticholinergic agents