Wendy7,Remeron (also known as mirtazapine) was approved by the FDA in 1996. It is primarily used as an antidepressant/antianxiety drug, but research suggests it may have additional uses in treating chronic pain, migraine headaches, some symptoms of Parkinson's Disease, and yes, D-predominant IBS.Remeron works in several ways. First it, like lotronex, blocks serotonin from stimulating the 5-HT3 receptor in the gut. The 5-HT3 receptor controls the gastrocolonic reflex; the "urge to go" after a meal. Blockade of the 5-HT3 receptor also improves pain tolerance, so the colon can hold more stool before "the urge" is generated. The differences between remeron and lotronex in regards to IBS-D are (1), remeron works equally well in men, (2), remeron has *not* been associated with ischemic colitis, and (3), remeron appears to exert a more potent blockade of the 5-HT3 receptor than lotronex, which may explain difference #1 above. Remeron also blocks serotonin at the 5-HT2 receptor. Blockade of this receptor improves sleep in those subjects who experience insomnia/anxiety. Blockade of the 5-HT2 receptor in animal models also appears to improve/increase sexual functioning, and one recent study with depressed subjects found the same result. Remeron is also blocks alpha andrenergic and histamine receptors. Blockade of alpha receptors indirectly increases levels of norepinephrine and serotonin, which contributes to the antidepressant/antianxiety effects of remeron. blockade of histamine receptors contributes to the improvement of sleep, plus (unfortunately) increased hunger.The most common side effects of remeron are weight gain, hunger, sleepiness, dry mouth and constipation. Like lotronex, remeron should not be prescribed to treat IBS-C subjects, although, as noted above, remeron use has not been associated with ischemic colitis. A very rare side effect of remeron is reduced white blood cell counts. Another rare side effect is an increase in cholesterol and triglyceride levels in the blood. A personal note: I've been using remeron since March. It has completely abolished my IBS. I wouldn't trade it for anything. I now have 1-3 BM/day, whereas I used to have 8-12. The only side effect I currently experience is occasional mild C, which is more than tolerable compared to my pre-remeron state. No more bloating, no more nausea, no more cramping or abdominal pain. I can eat whatever I want. I don't have to memorize the location of every bathroom in the shopping mall. And, if I do have the urge to "go", I can hold it until I find a restroom; no more sudden urgency. [This message has been edited by Guy (edited 11-03-2000).]