Tegaserod is a 5-HT4 agonist manufactured by Novartis and sold under the names Zelnorm and Zelmac for the management of irritable bowel syndrome and constipation. Approved by the FDA in 2002, it was subsequently removed from the market in 2007 due to FDA concerns about possible adverse cardiovascular effects. Before then, it was the only drug approved by the United States Food and Drug Administration to help relieve the abdominal discomfort, bloating, and constipation associated with irritable bowel syndrome. Its use was also approved to treat chronic idiopathic constipation. Mechanism of action
The drug functions as a motility stimulant, achieving its desired therapeutic effects through activation of the 5-HT4 receptors of the enteric nervous system in the gastrointestinal tract. It also stimulates gastrointestinal motility and the peristaltic reflex, and allegedly reduces abdominal pain. Additionally, tegaserod is a 5-HT2B receptor antagonist. Withdrawal from market
On 30 March 2007, the United States Food and Drug Administration requested that Novartis withdraw tegaserod from shelves. The FDA alleged a relationship between prescriptions of the drug and increased risks of heart attack or stroke. An analysis of data collected on over 18,000 patients demonstrated adverse cardiovascular events in 13 of 11,614 patients treated with tegaserod (a rate of 0.11%) as compared with 1 of 7,031 patients treated with placebo (a rate of 0.01%). Novartis alleged all of the affected patients had preexisting cardiovascular disease or risk factors for such, and further alleged that no causal relationship between tegaserod use and cardiovascular events has been demonstrated.
The breakpoints for 1p36 deletion syndrome have been variable and are most commonly found from 1p36.13 to 1p36.33. 40 percent of all breakpoints occur 3 to 5 million base pairs from the telomere. The size of the deletion ranges from approximately 1.5 million base pairs to greater than 10 million.Most deletions in chromosome 1p36 are de novo mutations. 20% of patients with 1p36 deletion syndrome inherit the disease from one parent who carries a balanced or symmetrical translocation. Diagnosis
1p36 deletion syndrome is usually suspected based on the signs and symptoms and confirmed by fluorescence in situ hybridization (FISH). Chromosomal microarray or karyotype analysis may also be used to diagnose 1p36 deletion. Treatment
There is no cure for 1p36 deletion syndrome, and treatment is focused on relieving symptoms of the disease. Of particular importance are appropriate medication for endocrine and neurologic manifestations, such as anti-seizure medications. Feeding difficulties can be managed with specialized assistive devices or with a gastrostomy (feeding) tube. Epidemiology
1p36 deletion syndrome is the most common terminal deletion syndrome in humans. It occurs in between 1 in 5000 and 1 in 10000 live births. And only 100 cases have been reported since 1981. == References ==