Home > MEDICATION & YOU > Drug Facts > Antidiarrheal


What is antidiarrheoal drug?

Antidiarrheal drugs are medications used to treat Diarrhea which is condition where you have loose, watery stools more than three times a day. Diarrhea can have many causes, which may be infectious or non-infectious. It might be caused by bacteria, viruses or parasites, certain medicines, food intolerances and diseases that affect the stomach, small intestine or colon. People with diarrhea often have fever and/or stomachache (abdominal cramps), bloating, nausea and an urgent need to have a bowel movement.

Types of antidiarrhoeal and general function

  1. Oral rehydration agents

    Oral rehydration agents are first line use as antidiarrheal agents. Maintenance of fluid and electrolyte balance is very important. It works to replace fluid and electrolytes loss from your body as a result from diarrhea.

  2. Loperamide

    Loperamide is antimotility agent. Antimotility medicines work by slowing down the movement of your gut, which reduces the speed at which the contents pass through. Food remains in your gut for longer and this allows more water to be absorbed back into your body. This results in firmer stools that are passed less often.

  3. Diphenoxylate – atropine

    It also antimotility agent which works by slowing down the movement of the bowels.

  4. Bismuth subsalicylate

    It is non specific agent. It works by balancing the way fluid moves through your intestines. It also reduces inflammation and keeps certain bacteria and viruses that cause diarrhea from growing in the stomach and intestines.

  5. Antibacterial agents

    Antibacterial agents can be used to treat diarrhea with confirmed bacterial cause, such as campylobacter. Otherwise antibacterial agents are not necessary in most cases of diarrhea.

  6. Antisecretory medicines

    Antisecretory medicines are a newer group of treatments. They are designed to be used with rehydration treatment. They reduce the amount of water that is released into the gut during an episode of diarrhoea. They can be used for children who are older than 3 months of age and adults.

How to take anti diarrheoal?

Antidiarreal drug should be taken as following:

  1. Loperamide 2mg Capsule

    Acute diarrhoea: ADULT: 4 mg stat, followed by 2 mg after each unformed stool (up to 5 days). Usual 6- 8 mg daily. Max: 16 mg daily.

    Chronic diarrhoea: Initially 4-8 mg daily in divided doses, adjust according to response. Max: 16 mg daily

  2. Diphenoxylate with Atropine Sulphate Tablet

    ADULT initially 4 tablet followed by 2 tablet 4 times daily until diarrhoea is controlled.

  3. Bismuth subsalicylate

    Oral: Subsalicylate (doses based on 262 mg/15 mL liquid or 262 mg tablets): 2 tablets or 30 mL every 30 minutes to 1 hour as needed up to 8 doses/24 hours.

  4. Oral rehydration salt

    ADULT: 200 – 400 ml ( 1 – 2 sachets ) for every loose motion.

    CHILD: 200 ml (1 sachet) for every loose motion. In severe dehydration 100 ml/kg for 3 – 4 hours.

    INFANT: 1 – 1.5 times their usual feed volume (50 ml per stool for small infant)

  5. Travelers who develop diarrhea (any watery stool) may benefit from antibiotic treatment. A typical three days illness can often be shortened to one day with early self treatment with an antibiotic. Anyhow they need to be evaluated by Medical Officer promptly: fever, more than mild vomiting or mild abdominal pain, blood mixed with diarrhea, or diarrhea which is severe or which does not resolve within 48 hours. Nausea and vomiting without diarrhea should not be treated with antibiotics.

Besides antidiarrheoal drugs, it is important to take plenty of fluid with sugar and salt to avoid dehydration. Salt and sugar together in a beverage help your intestine absorb fluids. Milk and dairy products should be avoided for 24 to 48 hours as they can make diarrhea worse. Initial dietary choices when refeeding should begin with soups and broth.

Special precaution

Don’t give loperamide to children 6 years of age or younger unless your doctor says it’s okay. People who are allergic to aspirin or other salicylate medicines should not take bismuth subsalicylate. Don’t give bismuth subsalicylate to children 12 years of age or younger.

You should seek for medical attention if you have a strong pain in your abdomen or rectum, a fever, blood in your stools, severe diarrhea for more than three days or symptoms of dehydration. In case of overdose please go to the nearest clinic or hospital for emergency treatment.

Side effects

Side effects may be a concern for older adults or people who have health problems. Some of the side effects are dizziness, drowsiness, tiredness, or constipation may occur. Stop taking this medication and seek immediate medical attention if any of these unlikely but serious side effects occur which are severe constipation, nausea, vomiting, stomach/ abdominal pain, uncomfortable fullness of the stomach/abdomen. Serious allergic reaction to this drug is rare.


The following healthy steps can help you prevent illnesses that cause diarrhea:

  1. Wash your hands often, especially after going to the bathroom and before eating.
    • Use alcohol-based hand gel frequently.
    • Teach children to not put objects in their mouth.
  2. When traveling to underdeveloped areas, follow the steps below to avoid diarrhea:
    • Drink only bottled water and do not use ice, unless it is made from bottled or purified water.
    • Do NOT eat uncooked vegetables or fruits that do not have peels.
    • Do NOT eat raw shellfish or undercooked meat
Last Reviewed : 06 January 2014
Writer : Aiza Adlina bt. Abdullah
Accreditor : Muslisah bt. Musa