Author: Jennifer Bowles

Jennifer is a clinical pharmacologist. She helps doctors of all medical specialties choose medications. Jennifer consults about drug dosage, interactions, and side effects.


Slightly soluble in water and in alcohol; sparingly soluble in methyl alcohol. A 0.1% solution in water has a pH of 4.4 to 5.4.

Drug Welchol for Hypercholesterolemia

Brand Name Drug: Welchol Active Ingredient Drug: colesevelam hydrochloride Indication: For the reduction of elevated low-density lipoprotein cholesterol in patients with primary hypercholesterolemia, as an adjunct to diet and exercise Company Name: GelTex Pharmaceuticals, Inc. An estimated 52 million people in the US have at least mild hypercholesterolemia and would benefit from lipid-lowering therapy.


Antispasmodics are drugs used for their relaxant action on smooth muscle, either direct or through an antimuscarinic action on the parasympathetic innervation. They play a role in the management of gastrointestinal spasm and irritable bowel syndrome (below) as well as other disorders associated with smooth muscle spasm. Those described in this site are mainly antimuscarinics drugs in other sites that may be used for relaxation of smooth muscle include calcium-channel blockers and nitrates, as well as tings with less well defined mechanisms of action such as papaverine.

Treatment of IBS. 5-HT3 Antagonists and 5-HT4 Agonists

According to Birrer, 96% of serotonin is concentrated in the gastrointestinal tract. As a major neurotransmitter, it exerts an effect on gut smooth muscle in response to central and physical stimuli primarily via the 5-HT3 and 5-HT4 receptors, affecting contractility and relaxation. Serotonin receptor antagonists may ameliorate the abnormal stool frequency and consistency in diarrhea-predominant irritable bowel syndrome (IBS) by blocking stimulation of the peripheral and visceral sensory pathways or by reducing the gut’s response to nociceptive stimuli.