Antispasmodics

What are antispasmodics?

Antispasmodics are a group (class) of medicines that can help to control some symptoms that arise from the gut (intestines) - in particular, gut spasm.

There are two main types, as follows.

• Antimuscarinics such as:

  • Dicycloverine.

  • Hyoscine.

  • Propantheline.

• Smooth muscle relaxants such as:

  • Alverine.

  • Mebeverine.

  • Peppermint oil.

• Antispasmodics are commonly used in Irritable Bowel Syndrome:

  • To help relieve some of the symptoms of irritable bowel syndrome (IBS) such as spasm (colic), bloating and abdominal pain.

  • To reduce the movement (motility) of the gut (intestines).

Note: Not everybody with IBS finds that antispasmodics work well. However, they are worth trying as they work well in a good number of cases.

• Antispasmodics are also used in some other conditions such as diverticular disease.

The movement of food along the gut (intestines) happens because some of the muscles in the gut contract and relax in a regular pattern throughout the length of the gut. These muscle contractions are brought about by various chemicals produced by the body which stick to special "docking sites" (receptors) on the muscles.

However, in conditions such as irritable bowel syndrome (IBS) these muscle contractions can occur too often or be painful, causing symptoms such as pain and bloating.

Antimuscarinics work by attaching to the receptors and, in this way, stop the chemicals from 'docking' there. This stops or reduces the muscle contractions which can help 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 therefore cause a dry mouth as a side effect.

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.

• It is often recommended to use the medicine at a particular time in relation to eating.

• Some people take a dose before meals if pains tend to develop after eating.

It is generally recommended that you take these medicines only when necessary. For example, people with IBS commonly find that there are times when their symptoms flare up for a while and then settle down. So, it is common to take an antispasmodic when symptoms flare up, and to stop them if symptoms reduce again.

Note: pains may ease with medication but may not go away completely.

Most people can take antispasmodics. There are a few exceptions. A full list of people who should not take antispasmodics is included with the information leaflet that comes with the medicine packet.

In particular, antispasmodics may not be suitable for people with:

• Paralytic ileus - a condition where the gut (intestinal) muscles are paralysed.

• A blocked gut (intestinal obstruction).

• Myasthenia gravis - a condition causing muscle weakness.

• Pyloric stenosis - narrowing of the outlet from the stomach.

• Prostate gland enlargement.

Pregnant or breastfeeding mothers should seek advice before using these medicines. Where possible, it is usually recommended to avoid these medicines when pregnant.

Most people who take antispasmodics do not have any serious side effects. If side effects do occur, they are usually minor. In general, the smooth muscle-relaxant medicines have fewer side effects, although the side effects do depend on which one is taken. Some of the more common side-effects are:

• Heartburn.

• Constipation.

• Dry mouth.

• Difficulty passing urine.

Note: the above is not the full list of side-effects for these medicines. Please see the information leaflet that comes with the medicine for a full list of possible side-effects and cautions.

These medicines sometimes react with other medications so it is important that the pharmacist and doctor know of any other medicines being taken, including ones that have been bought rather than prescribed.

Other considerations

People with IBS may become used to having gut (intestinal) symptoms. However, it is important not to assume that all gut symptoms are due to the IBS. Medical advice should be sought if experiencing any change in the usual pattern of symptoms. In particular, the following problems can indicate a serious gut disorder:

• Unintentional weight loss.

• Bleeding from the back passage (rectum).

• Blood in your stools (faeces) - this may colour the stools black.

• A change in the bowel habit, lasting 3 weeks or more, particularly to looser stools, or passing stool more frequently than usual.

• Bloating that does not fully resolve or is getting worse.

How quickly do antispasmodics work?

Antispasmodics usually work within an hour or so to ease symptoms.

How long is treatment needed for?

These medicines are usually only used for active symptoms. However, this can vary depending on the reason for treating you. Your doctor should be able to advise you on this.

Can I buy antispasmodics?

Many antispasmodics can be bought from a pharmacist. Others are only available with a prescription.