Antispasmodics are defined as a medication or drug used to relieve spasm of involuntary muscle. There are two main types of antispasmodics: antimuscarinics, including atropine, hyoscine, dicyloverine, and propantheline, and smooth muscle relaxants, such as alverine, mebeverine, and peppermint oil. Antimuscarinics work by attaching to the receptors and in this way stopping the chemicals from 'docking' there to make the muscle contract. Reducing the muscle contractions in this way often helps to relieve some of the symptoms caused by IBS. Because muscarinic receptors are also found in other parts of the body, taking an antimuscarinic can have other effects. For example, muscarinic receptors also help to control the production of saliva in the mouth. Taking a medicine that blocks these receptors may cause a dry mouth. Smooth muscle relaxants work directly on the smooth muscle in the wall of the gut. Here they help to relax the muscle and relieve the pain associated with a contraction of the gut. The smooth muscle relaxants tend to have fewer side-effects, so they are usually tried first. It is generally recommended that a person take these medicines only when necessary. For example, people with IBS commonly find that there are times when symptoms flare up for a while. So, it is common to take an antispasmodic when symptoms flare up, and to stop them if symptoms settle down. Possible side effects of antispasmodics are heartburn, unusual bleeding, skin rash, fever, yellow skin or eyes, sore throat, hives, eye pain, decreased sweating, memory loss, headache, dry skin, decreased flow of breast milk, headache, difficulty swallowing, increased sensitivity to light, drowsiness, blurred vision, dry eyes, nausea, abdominal bloating, constipation, dry mouth, and difficulty passing urine. Severe side effects may be more likely to occur in infants and children, especially those with spastic paralysis or brain damage. Unusual excitement, nervousness, restlessness, or irritability and unusual warmth, dryness, and flushing of skin are more likely to occur in children, who are usually more sensitive to the effects of belladonna alkaloids. Also, when belladonna alkaloids are given to children during hot weather, a rapid increase in body temperature may occur. In addition, the barbiturate in this medicine could cause some children to become hyperactive. Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Medical problems such as asthma, enlarged prostate, hyperactivity, ulcerative colitis, heart disease, glaucoma, emphysema, down’s syndrome, kidney disease, or liver disease may also worsen the side effects of antispasmodic medications.