Antispasmodics and Antiemetics

Intestinal spasm and Vomiting

Intestinal spasm refers to the involuntary contraction of the smooth muscles in the intestines. This condition may be accompanied by symptoms such as bloating, abdominal pain, diarrhoea and constipation. Vomiting, known as emesis, is the forceful expulsion of the stomach’s contents through the mouth.

Intestinal spasm commonly occurs in conditions, such as gastroenteritis, food allergy, irritable bowel syndrome, and as a response to emotional stress. Vomiting is a common symptom associated with gastroenteritis, morning sickness of early pregnancy, food poisoning, motion sickness, migraine, vertigo, and can also be an adverse reaction to chemotherapy and anaesthesia. Severe vomiting may result in dehydration and electrolyte imbalance.

Antispasmodics

Antispasmodics are medications that help relax smooth muscles, thereby alleviating spasmodic pain. These medications can be classified into two main types:

• Smooth muscle relaxants (e.g. alverine and mebeverine)
• Anticholinergics (e.g. hyoscine)

Most commonly used antispasmodics are generally classified as pharmacy-only or prescription-only medicines and are available in various dosage forms, such as tablets, capsules, syrups, injections and patches.

Common Side Effects and Precautions of Antispasmodics

General Advice on Taking Antiemetics*

• Antispasmodics are primarily for symptomatic relief and should not be considered a permanent cure, therefore, prolonged use should be avoided.
  
  
• Avoid driving or operating machinery if you experience drowsiness or blurred vision after taking the medicine.
  
  

Antiemetics

Antiemetics are medications that act by inhibiting the receptor sites associated with emesis. Several classes of antiemetics are available, including:

• Anticholinergics (e.g. hyoscine)
• Antihistamines (e.g. promethazine and dimenhydrinate)
• Dopamine antagonists (e.g. metoclopramide, domperidone, and phenothiazines: prochlorperazine, chlorpromazine)
• 5HT3-receptor antagonists (e.g. ondansetron, granisetron, palonosetron)
• Neurokinin-1 receptor antagonists (e.g. aprepitant, fosaprepitant, netupitant)

The choice of antiemetics depends on the underlying cause of vomiting. For example, hyoscine or antihistamines are commonly used for motion sickness, while 5HT3-receptor antagonists and neurokinin-1 receptor antagonists are typically used in the management of vomiting in patients undergoing chemotherapy and postoperative vomiting.

Most commonly used antiemetics are generally classified as pharmacy-only or prescription-only medicines and are available in various dosage forms, such as tablets, capsules, syrups, injections, suppositories and patches.

Common Side Effects and Precautions of Antiemetics

General Advice on Taking Antiemetics*

• Antiemetics provide temporary symptomatic relief and do not address the underlying cause of nausea and vomiting, therefore, prolonged use should be avoided.
  
  
• Do not drive or operate machinery after taking antiemetics, as many of these medicines may cause drowsiness.
  
  
• Do not consume alcohol while taking antiemetics.
  
  
• After vomiting, refrain from solid food for a few hours and continue to take small sips of fluid frequently to prevent dehydration.
  
  

Communication with Your Doctor*

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

• If your vomit is green or contains blood, please seek urgent medical consultation.

• 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.