Antispasmodics and Antiemetics

Intestinal spasm and vomiting

Intestinal spasm is the uncontrolled muscle contraction of the large and small intestines. It may also be accompanied by bloating, abdominal distention, diarrhoea and constipation. Vomiting or throwing up (also known as emesis) is forcing the contents of the stomach up through the esophagus and out of the mouth.

Both of them are not diseases but are very common symptoms of many underlying medical conditions. Intestinal spasm commonly occurs in irritable bowel syndrome, gastroenteritis, food allergy and emotional stress. Vomiting is one of the common symptoms in gastroenteritis, morning sickness of early pregnancy, food poisoning, travel sickness, severe pain, migraine, vertigo, and is one of the adverse reactions of chemotherapy and anaesthesia. Severe vomiting may lead to dehydration and electrolyte imbalance.

Treatment used

The ultimate treatment for both intestinal spasm and vomiting is to find out the underlying cause and get proper treatment under medical supervision. When the symptoms persist despite the underlying cause has been treated, drugs of antispasmodics and antiemetics (anti-sickness pills) can be considered to alleviate intestinal spasm and relieve vomiting respectively. Besides, antiemetics can be used to prevent vomiting in situations where it can be anticipated, such as travel sickness, morning sickness, chemotherapy or surgery.

Antispasmodics

Antispasmodics relax the smooth muscles, thereby relieve spasmodic pain. They are classified into two main types: smooth muscle relaxants such as alverine and mebeverine, and anticholinergics such as hyoscine.

Most of the antispasmodics are either pharmacy only medicines or prescription medicines. They are available in many dosage forms such as tablets, capsules, syrups, injections and patches.

Common side effects and precautions of antispasmodics

General advice on taking antispasmodics

• Antispasmodics are mainly for symptomatic relief rather than a permanent cure, therefore excessive use of these drugs should be avoided.
  
  
• As antispasmodics may suppress symptoms and hinder the finding of underlying illness, these should not be taken without medical consultation. Delay in treating the underlying illness may result in serious consequence.
  
  
• It is advisable to take antispasmodics 30 minutes to an hour before meals or as instructed by the doctor.

Antiemetics

Antiemetics act by inhibiting the receptor sites associated with emesis. There are a variety of choices but commonly used antiemetics include antihistamines (e.g. promethazine and dimenhydrinate), anticholinergics (e.g. hyoscine), phenothiazines (e.g. prochlorperazine), dopamine antagonists (e.g. metoclopramide and domperidone), and 5HT3- receptor antagonists (e.g. ondansetron and granisetron). The choice of antiemetics depends mainly on the cause of vomiting. For example, hyoscine and antihistamines are the principal drugs used for preventing travel sickness whereas 5HT3-receptor antagonists are of value in the management of vomiting in patients receiving chemotherapy and in postoperative vomiting.

Most of the commonly used antiemetics are pharmacy only medicines or prescription medicines. They are available in forms of tablets, capsules, syrups, injections, suppositories and patches.

Common side effects and precautions of antiemetics

General advice on taking antiemetics

• Antiemetics are mainly for symptomatic relief rather than a permanent cure, therefore excessive use of these drugs should be avoided.
  
  
• As antiemetics may suppress symptoms and hinder the finding of underlying illness, these should not be taken without medical consultation. Delay in treating the underlying illness may result in serious consequence.
  
  
• Do not drive or operate machinery after taking antiemetics, as most of them may make you feel drowsy.
  
  
• Antiemetics should not be taken with alcohol, as most of them have the effect of suppressing the central nervous system and alcohol could strengthen such effect, thereby may cause harmful effects.
  
  
• Avoid solid food within a few hours after vomiting, and take more rest and keep taking small sips of fluid to prevent dehydration.
  
  
• Avoid strong smells and other triggers such as heat and flickering lights, which can help to relieve vomiting.
  
  

Communication with your doctor

• Seek medical advices before taking antispasmodics and antiemetics, especially if you are pregnant or breastfeeding.

• Do not give antispasmodics and antiemetics to children and elderly without medical advice, since they are more prompt to drug adverse reactions.

• Consult the doctor and do not stop medications by yourself if vomiting is an effect of the drugs that you are taking.

• If your vomit is green or with blood, please seek medical advice immediately.

• Seek immediate medical attention if vomiting lasts for more than 24 hours, or is accompanied by severe stomach pain or headache, or you are unable to keep down fluids for more than 12 hours.