3 Effective OTC Medications For Diarrhea

The 3 most commonly used and effective OTC medications for diarrhea are:

  • Loperamide
  • Bismuth Subsalcylate, and
  • Attapulgite

The following discussion focuses on answering the following questions:

  • How do these medications act?
  • When to use these medications?
  • What are the side effects of OTC medications for diarrhea?
  • When you should not treat your diarrhea at home?

What is acute, chronic, and persistent diarrhea?

Diarrhea occurs when stool contains an excess amount of water, resulting in loose and runny stools.

This disease develops when the small and large intestines are unable to absorb necessary ions, such as salt, which makes it difficult for the body to hold onto water and results in watery stools.

There are two primary classifications of diarrhea:

  • Acute diarrhea and
  • Chronic diarrhea

Acute diarrhea involves the passage of at least three loose stools a day, lasting up to 14 days.

Infection is the most frequent cause of acute diarrhea. The majority of cases are caused by a viral infection, and they resolve on their own.

Persistent diarrhea lasts 2 to 4 weeks. It is caused commonly by infections such as giardiasis, entameba histolytica, E.coli, campylobacter, shigella, and salmonella.

Chronic diarrhea extends beyond 4 weeks. Malabsorption, inflammatory bowel disease, chronic infections such as tuberculosis, cancers of the GI tract, HIV infections, and adverse drug reactions are common causes [ref].

There are various medications for diarrhea depending on the underlying cause. In most cases, treatment goals are to improve intestinal fluid absorption and regulate gastrointestinal motility.

Most of the time, over-the-counter medications like loperamide (Imodium) and bismuth subsalicylate (Pepto-Bismol, Kaopectate) can be used to treat acute diarrhea.

If a patient has a fever or bloody stools—symptoms of a bacterial or parasitic infection—the use of OTC medications for diarrhea should be avoided.


OTC Medications for Diarrhea:

The three over-the-counter medications that are typically used to treat diarrhea are as follows:

1.   Loperamide (Imodium)

Loperamide is an over-the-counter medication used to relieve diarrheal symptoms. It is also available under the brand name Imodium. 

It comes in various forms, including liquid, tablets, and capsules, and is an effective tool for controlling loose stools.

  • Loperamide’s Mechanism of Action

Loperamide’s primary function is to slow down intestinal movement. This reduces the frequency of watery stools by giving the body more time to absorb water and electrolytes.

Thus, it reduces the symptoms of diarrhea and restores intestinal regularity.

  • Imodium over-the-counter dosage and administration:

Imodium OTC dosing schedule should be followed as per the recommendations provided in the packaging information.

Here is a table of Imodium over the counter dose according to the age:

Age Group

Weight Range (kg)

Initial Dose

Doses after each loose stool

Maximum Daily Dose

2 to 5 years13 to <211 mg1 mg3 mg/day
6 to 8 years21 to 272 mg1 mg4 mg/day
9 to 11 years27.1 to 432 mg1 mg6 mg/day
≥12 years (Adolescents)4 mg2 mg8 mg/day
Adults 4 mg2 mg16 mg

Adherence to these guidelines ensures medication efficacy while minimizing potential side effects.

  • Importance of adequate hydration:

It is critical to drink plenty of water while using Loperamide. Drinking plenty of fluids is recommended to replace any fluids lost due to diarrhea and aid in the body’s healing process.

There are plenty of OTC fluid and electrolyte-balanced solutions available.

Alternatively, one can make a balanced electrolyte solution at home as well as per the WHO recommendations [Ref]:

  • Boil 5 glasses (200 ml) of water and wait for it to cool down to room temperature
  • Add Six TSP of table sugar
  • Add 1/2 TSP of table salt

The ORS solution made at home must be used within 24 hours. It is preferred to take half to one glass of ORS after every loose stool in addition to the daily requirement of 2 liters or more.

  • Side effects of Loperamide:

The following are possible loperamide side effects:

  • Dizziness and lightheadedness
  • Xerostomia
  • Nausea
  • Stomach cramps while passing wind
  • Constipation
  • Fatigue
  • Having difficulty emptying the bladder

It is also important to note that loperamide is not a controlled substance, and there is a risk of overdose and severe side effects.


2.   Bismuth subsalicylate (Pepto-Bismol, Kaopectate)

Bismuth subsalicylate is an effective diarrhea treatment and is commonly found in over-the-counter medications such as Kaopectate and Pepto-Bismol.

It is available in a variety of forms, including liquid and chewable tablets, and is designed to relieve symptoms of upset stomach and loose stools.

  • How does Bismuth Subsalicylate Work?

This medication soothes inflammation and reduces irritation by coating the irritated stomach and intestinal lining.

Because of its antimicrobial properties, it can also help fight off specific bacteria that may be causing diarrhea.

  • Dosage and Administration:

A general guideline about Bismuth dosing is given in the table below:

Age Group




Maximum Doses per Day

Children (3-6 years)Regular87 mgEvery 60-90 minutes as necessary8
Children (6-9 years)Regular175 mgEvery 60-90 minutes as necessary8
Children (9-12 years)Regular262 mgEvery 60-90 minutes as necessary8
Adolescents (≥12 years)Regular524 mgEvery 30 minutes to 1 hour as needed8
Adolescents (≥12 years)Maximum1050 mgEvery hour as needed4

Following the dosage instructions on the package or as directed by a medical professional is critical.

Adults and children can usually take bismuth subsalicylate at prescribed intervals; the duration of treatment is determined by the severity of the symptoms.

Following these guidelines is critical to ensuring its effectiveness while remaining within safe limits.

  • Additional Benefits:

Bismuth subsalicylate not only relieves diarrhea but also heartburn, nausea, and indigestion, making it a one-stop shop for gastrointestinal problems.

  • Side effects:

Bismuth subsalicylate may cause the following side effects:

  • Nausea
  • Bitter taste
  • Dark or black stool
  • Anxiety
  • Confusion
  • Headache
  • Tinnitis (ringing bells in ears)
  • Weakness and
  • Muscle spasms

3.  Activated Attapulgite (Entox-P, Kaopectate):

Attapulgite is magnesium aluminum phyllosilicate. It is available as a co-formulation with Bismuth subsalicylate.

  • How does Attapulgite work?

Bacterial, toxins, chemicals, and water get adsorbed to the surface of attapulgite making firm stools and reducing water loss from the GI tract.

  • Dosage and Administration:

It is available as 750 mg per 15ml solution and 600 mg tablets. The dosing schedule per mg of the drug is given in the table below:

Patient Group

Dose per Loose Bowel Movement

Maximum Daily Dose

Children ≥12 years and Adults1.2-1.5 g8.4 g (24 hours)
Children (6-12 years)600-750 mg4.5 g (24 hours)
Children (3-6 years)300 mg2.1 g (24 hours)

The dosing schedule for solutions (750 mg/15 ml) and tablets (600 mg) is given in the table below:

Patient Group

Adults, Children ≥12 years, Geriatric Patients

Children (6-12 years)

Children (3-6 years)

Dose per Loose Bowel Movement (Tablet)1-1.25 tablets1 tablet or 1.25 tablets0.5 tablet
Dose per Loose Bowel Movement (Solution)1-1.25 tablespoons (15-18.75 ml)1 tablespoon (15 ml) or 1.25 tablespoons (18.75 ml)0.5 tablespoon (7.5 ml)
Maximum Daily Dose (Tablet)5-7 tablets3 tablets2 tablets
Maximum Daily Dose (Solution)5-7 tablespoons (75-112.5 ml)3 tablespoons (45 ml)2 tablespoons (30 ml)
  • Side Effects and Contraindications:

Common side effects include:

  • Abdominal gases
  • Flatulence
  • Nausea
  • Constipation

Who should not use OTC Medications for Diarrhea?

You should refrain from using over-the-counter diarrhea drugs if you have the following conditions:

  • Parasitic or bacterial infections:

If bacteria or parasites cause your diarrhea, avoid using anti-diarrhea medications. Your body has to eliminate the parasite or bacteria causing the diarrhea if you have a “stomach bug.”

In this situation, giving up on the diarrhea could make things worse. If you suspect that you have a parasitic or bacterial infection, see your family physician.

  • Loperamide precautions:

Loperamide can cause severe or fatal changes in heart rhythm, particularly in people who have taken more than the recommended amount.

Inform your physician if you suffer from or have ever had low potassium in your blood, slow or irregular heartbeats, or a prolonged QT interval—a rare heart condition that can result in irregular heartbeats, fainting, or abrupt death.

If your doctor still needs to give the all-clear, do not give loperamide to children two years of age or younger.

It may raise the chance of developing severe cardiac and breathing issues. Additionally, consult your physician before giving loperamide to older kids. If you have a temperature, you should not take loperamide.

Do not use it if you have ever taken it and experienced a rash or allergic reaction. If your stool is black or bloody, avoid taking loperamide. These could be signs of a more intense issue, like an infection caused by bacteria.

  • Bismuth subsalicylate warnings:

Aspirin and other salicylate medications can cause allergies in specific individuals. Bismuth subsalicylate should not be administered to them.

Please give it to no one younger than 15 who has chickenpox or the flu. Furthermore, this drug may interact with other medications.

It is contraindicated in individuals taking dexketoprofen (used for pain relief), sulfinpyrazone (used to treat gout), and bismuth subcitrate.

It should be avoided after Influenza vaccine (live or attenuated). There is a risk of Reye’s syndrome, a fatal liver failure.

As a result, it is recommended to consult a doctor before using it if a person takes any medications for:

  • Arthritis
  • Anticoagulation
  • Gout
  • Diabetes

Frequently Asked Questions

  • What is the quickest method for treating diarrhea?

Most cases of diarrhea clear up on their own without any medical intervention.  But if your symptoms do not improve in two days, your doctor might recommend some medication.

  • How to safely store over-the-counter antidiarrheal medications?

It is essential to store all medications high and out of the reach and sight of small children.

Medications stored in a dry, cool environment will be less likely to lose effectiveness before expiration.

Since bathrooms and cabinets are often hot and muggy, it is best to store medications elsewhere.

  • Which medication is the first one prescribed for diarrhea?

Over-the-counter medications like loperamide and bismuth subsalicylate are commonly used to treat acute diarrhea. In other cases, prescription medications like alosetron, eluxadoline, and rifaximin.



Diarrhea is typically defined as passing watery stools at least three times per day.

It can be caused by a variety of factors, and the condition can be either acute or chronic depending on how long it lasts. Severe complications may arise from the condition if left untreated.

There are over-the-counter (OTC) options that are developed to increase the absorption of fluids and slow the passage of contents through the intestines.

Diarrhea typically goes away within a few days. But it is best to get in touch with a doctor if symptoms last longer than two days.

What do you think?

Written by Dr. Ahmed

I am Dr. Ahmed (MBBS; FCPS Medicine), an Internist and a practicing physician. I am in the medical field for over fifteen years working in one of the busiest hospitals and writing medical posts for over 5 years.

I love my family, my profession, my blog, nature, hiking, and simple life. Read more about me, my family, and my qualifications

Here is a link to My Facebook Page. You can also contact me by email at or at My Twitter Account
You can also contact me via WhatsApp 🙏

signs of vitamin c deficiency and treatment how to lose face fat exercises for chubby cheeks

Signs and Treatment of Vitamin C Deficiency

high protein low carb breakfast after gastric sleeve oats for diabetes patients

7 High Protein Low Carb Breakfast After Gastric Sleeve