Antidiarrheal medication list

Key takeaways

Antidiarrheals fall into four working groups: opioid receptor agonists, adsorbents, bismuth compounds, and probiotics. Each one targets a different part of the problem.

Loperamide and bismuth subsalicylate are the over-the-counter options. Diphenoxylate, octreotide, and bile acid sequestrants need a prescription.

Antimotility agents are off the table in suspected Clostridioides difficile colitis or bloody diarrhea. Screen for red flags before you recommend one.

Current guidance advises avoiding bismuth subsalicylate for the whole of pregnancy, because of its salicylate content.

Download the medication list so every clinician works from the same doses, contraindications, and escalation criteria.

Diarrhea turns up every week in primary care, urgent care, and gastroenterology. Most clinicians reach for the same one or two agents and never work through the rest of the list. The harder questions are which drug fits which presentation, what the labeled adult dose is, and when a medication is the wrong answer.

This antidiarrheal medication list organizes the FDA-approved agents by class, mechanism, and prescribing status. It gives adult dosing, the indications for acute and chronic diarrhea, and the red flags that rule a drug out. Print it, laminate it, or keep it open on a tablet during rounds.

Inside you will find the drug classes, the over-the-counter and prescription split, antibiotic-associated diarrhea, the reference table, side effects, and escalation criteria.

What are antidiarrheal medications?

Antidiarrheals are drugs that reduce the frequency and water content of loose stools. The clinical definition of diarrhea used by the WHO, the CDC and the NIH is three or more loose stools in 24 hours.

The agents reach that goal by different routes. Some slow intestinal motility, some bind pathogens and toxins, and others cut secretion or restore beneficial bacteria. For prescribing purposes they split into over-the-counter agents and prescription-only medications kept for more complex presentations.

Unlike antibiotics or antiemetics, antidiarrheals are symptom-management tools. They do not treat the underlying infectious, inflammatory, or functional cause. That distinction decides safety as much as it decides efficacy. Giving one to a patient with suspected Clostridioides difficile or bloody diarrhea can make the outcome worse.

So the clinician’s job is to pick the right agent for the right patient, or to pick none at all. Contraindication screening comes first, every time.

Where the list fits in your workflow

The template is built to follow the patient through the visit. Use it at five points:

1. Patient intake: When a patient reports acute diarrhea, check which over-the-counter agent matches their symptom timeline and risk factors. Note any red flag that rules an antidiarrheal out, including bloody stools, fever, antibiotics in the past two weeks, and immunocompromise.
2. Prescriber decision: For chronic refractory diarrhea or post-surgical sequelae, cross-reference the drug class, mechanism, and patient-specific contraindications. Check interactions against the patient’s current medications, particularly anticholinergics and opioids.
3. Patient counseling: Share the dose and the expected timeline. Loperamide usually cuts stool frequency within one to two hours. Bismuth subsalicylate is gentler but needs dosing every 30 to 60 minutes. Say plainly that these treat the symptom, not the infection.
4. Follow-up and safety monitoring: Record the agent, the dose, and the response in the patient chart. Flag adverse effects: constipation with loperamide, salicylate reactions with bismuth, or CNS effects with diphenoxylate. Book a call or visit within 48 to 72 hours for acute cases.
5. Escalation and referral: Use the red-flag criteria to recognize when an antidiarrheal is the wrong call and gastroenterology or infectious disease should see the patient.

Before you add an antidiarrheal for a patient already taking several drugs, work through a structured medication review. Anticholinergic and opioid overlap is the interaction that most often turns a routine recommendation into an adverse event.

Review the template quarterly, as new formulations and FDA safety communications appear. Give one person the job of keeping it current: a nurse, a pharmacist, or the practice manager.

Who the list is for

This reference is written for:

• Primary care physicians and nurse practitioners: Managing acute and chronic diarrhea in office-based or urgent care settings. A quick dosing check matters more here than a literature search.
• Gastroenterology practices: Handling the complex cases, including post-surgical, medication-induced, and refractory diarrhea, with a standardized contraindication and interaction check.
• Hospital and practice pharmacy teams: Building formulary policy, dispensing workflows, and patient education around antidiarrheal selection.
• Nursing staff and medical assistants: Answering the patient who asks which over-the-counter option to take, and what to watch for once they start it.
• Infectious disease and travel medicine practices: Coordinating the choice of agent with antibiotic therapy, particularly for traveler’s diarrhea and antibiotic-associated diarrhea.
• Functional and integrative medicine practices: Weighing the pharmaceutical options against probiotics and dietary changes for chronic loose stools.

Practices running on primary care practice software can attach the list to the intake template. It then opens with the chart, instead of sitting in a drawer at the nurses’ station.

What a shared reference changes

Faster decisions: One printable page removes the search through three sources for a drug name, a dose, and a contraindication while the patient waits.

Consistent screening: A standardized list means every clinician applies the same red-flag check before recommending an agent. That is what keeps an antimotility drug away from the patient who should not have one.

Cleaner documentation: When staff record which antidiarrheal was recommended and why, the note is structured and auditable. Compliance review then has something to read rather than something to reconstruct.

Team alignment: Shared access means nurses, physicians, and front-desk staff describe loperamide, bismuth, and the prescription agents the same way. Patients hear one answer, which helps adherence.

Formulary control: Listing every available agent alongside its indication lets practice managers negotiate pricing and coverage on the options they actually use.

The complete reference table

This table is the core of the download. It organizes the major FDA-approved agents by drug class, mechanism, and prescribing status. You can find a dose, a status, or a warning in one look.

All dosing reflects FDA labeling and current clinical guidance as of 2026. Availability differs outside the US, so check local formularies and regulatory databases for the UK, Australia, and Canada.

Over-the-counter agents vs. prescription agents

The list splits along two regulatory pathways. Over-the-counter agents, loperamide and bismuth subsalicylate, are sold without a prescription and suit acute, mild to moderate diarrhea in low-risk patients. Prescription agents are kept for chronic or refractory cases, once a clinician has ruled out an infectious or inflammatory cause.

The logic behind the split is exposure. The over-the-counter agents have decades of safety data and manageable risks for a patient who reads the label. The prescription agents carry more complexity, from DEA scheduling for diphenoxylate to the narrow secretory-diarrhea indication for octreotide.

Over-the-counter does not mean risk-free. Children under two, pregnant patients, and immunocompromised patients should avoid these drugs altogether.

The order of the decision matters more than the drug list itself. Screening comes first, and only a clean screen opens the question of which agent fits.

Side effects and warnings by drug class

Every antidiarrheal carries a risk profile to weigh against the benefit. The classes below cover the common and the serious adverse effects, which is what you counsel on and what you monitor for.

• Opioid receptor agonists (loperamide, diphenoxylate): Constipation, abdominal cramping, dizziness, and drowsiness. Rare but serious: toxic megacolon, ileus, and opioid dependence with long-term diphenoxylate. Loperamide overdose causes CNS effects, including lethargy and loss of consciousness.
• Bismuth subsalicylate: Harmless darkening of the tongue and stool, nausea, and salicylate reactions in sensitive patients. Reye syndrome is a risk in children with chickenpox or influenza, so avoid it in pediatrics. High doses can cause tinnitus or hearing loss.
• Diphenoxylate/atropine: Combines opioid and anticholinergic risks, so expect dry mouth, tachycardia, urinary retention, and blurred vision. CNS depression and physical dependence are the reason for Schedule V status. The atropine is there to deter abuse.
• Octreotide: Injection-site pain, hyperglycemia, and cholelithiasis with long-term use. In untreated carcinoid syndrome it can precipitate a carcinoid crisis. It is expensive, so it stays reserved for refractory secretory diarrhea.
• Bile acid sequestrants (cholestyramine): Constipation, bloating, and malabsorption of vitamins A, D, E, K and B12 over the long term. It binds many drugs, so dose separation is required. Elevated triglycerides are a contraindication.
• Probiotics: Generally well tolerated, with occasional gas, bloating, or allergic reaction. Patients with neutropenia, active sepsis, or a central line face a risk of bacteremia and of fungemia with Saccharomyces species.
• Adsorbents (kaolin-pectin): Constipation, worsened dehydration in a fluid-depleted patient, and nutrient malabsorption. It also binds other drugs, so separate doses by two to three hours. Note that it left the US market in 2004.

Counsel every patient on the timeline. Loperamide and bismuth subsalicylate usually reduce stool frequency within one to two hours, while probiotics and dietary changes take three to seven days. Adsorbent and bile acid agents can deepen fluid loss, so a dehydration skin test at follow-up catches the problem before it becomes a referral.

Antibiotic-associated diarrhea: Which agents are safe?

Antibiotic-associated diarrhea is its own clinical scenario, and it changes the answer. Antibiotics disrupt normal gut flora, which lets Clostridioides difficile and other pathogens proliferate. The list flags which agents to avoid here and which may help.

Contraindicated: Antimotility agents, loperamide and diphenoxylate, are absolutely contraindicated in suspected or confirmed C. difficile colitis. They raise the risk of toxic megacolon and worsen outcomes. If testing is pending and symptoms are severe, avoid them entirely.

Safe or potentially useful: Probiotics and bismuth subsalicylate have evidence in mild to moderate antibiotic-associated diarrhea, for restoring flora and reducing stool frequency. Neither replaces antibiotic therapy for confirmed C. difficile, which needs metronidazole, vancomycin, or fidaxomicin. Adsorbents are neutral, and kaolin-pectin is no longer sold in the US anyway.

Document the antibiotic used, the timing of onset, and whether C. difficile testing was ordered. Onset within 48 hours of starting the antibiotic is typical, and that detail shapes the next prescribing decision as well as any compliance audit.

When to refer or escalate

This list supports symptom management, not diagnosis. Knowing when to withhold an antidiarrheal matters as much as knowing which one to give. The following findings warrant escalation to urgent care, the ED, or a specialist:

• Bloody or black tarry stools: Suggests gastrointestinal bleeding or severe mucosal inflammation, including ulcerative colitis, ischemic colitis, and shigellosis. Refer to the ED or a GI specialist.
• Fever above 38.5°C (101.3°F) with diarrhea: Points to an infectious or inflammatory process. Withhold antimotility agents and refer for evaluation and testing, including stool culture and C. difficile PCR.
• Severe abdominal pain or distension: May indicate appendicitis, diverticulitis, toxic megacolon, or a surgical abdomen. Refer to the ED immediately.
• Signs of severe dehydration: Orthostatic hypotension, altered mental status, dry mucous membranes, poor skin turgor, and reduced urine output. Refer to the ED for IV rehydration.
• Diarrhea lasting more than 7 days despite treatment: Suggests chronic or underlying pathology such as IBD, celiac disease, IBS, or malabsorption. Refer to a GI specialist for a diagnostic workup.
• Diarrhea after starting antibiotics, with fever and severe symptoms: Suspect Clostridioides difficile infection. Withhold antimotility agents, order testing with PCR preferred, and refer for antibiotic therapy rather than an antidiarrheal.
• Immunocompromised patient: With HIV or AIDS, neutropenia, active chemotherapy, or a transplant, avoid probiotics and antimotility agents. Diarrhea here can signal opportunistic infection or drug toxicity, so refer to infectious disease.
• Pregnancy: Current guidance advises avoiding bismuth subsalicylate for the whole of pregnancy, because salicylate exposure carries fetal risk. Loperamide is the preferred option, and only where the benefit outweighs the risk. Refer to OB/GYN before recommending either.

Record where the pain sits before you escalate, because that description travels between the nurse who takes the call and the provider who reviews it. A stomach pain chart keeps it consistent, and it gives the specialist something concrete to work from.

Note the specific red flag and the action taken in the patient chart. That entry supports continuity of care, and it protects the practice if the patient deteriorates after an initial recommendation.

How Pabau keeps the medication decision in the patient record

In most practices the antidiarrheal recommendation lives in three places at once. The nurse writes it in a phone note, the provider dictates it into the visit summary, and the follow-up call goes in a diary. When the patient calls back on day three, nobody can see the dose that was given.

Practice management software like Pabau keeps all three in one client record. The agent, the dose, the red flags you screened for, and the follow-up date sit on the same timeline as the appointment. Custom intake forms can ask the screening questions before the patient reaches the room, so the answers arrive with the chart.

Medical records software then holds the audit trail: who recommended what, on what evidence, and what happened next. That is the record you want when a patient deteriorates after an over-the-counter recommendation.

Keep every medication decision in one record

Pabau brings intake screening, prescribing notes, and follow-up scheduling into one client record. Your team can see which antidiarrheal was recommended, why, and what happened next.

Book a demo

Conclusion

The judgment this list encodes is straightforward. Screening decides whether a drug belongs in the conversation at all, and only then does the class decide which one.

Two entries here catch out anyone working from memory. Kaolin-pectin has not been the Kaopectate formulation since 2004, and bismuth subsalicylate is now advised against for the whole of pregnancy. Both are easy to get wrong at speed, which is the argument for a shared reference over individual habit.

Keep the list where the decision happens rather than in a folder, and revisit it whenever the FDA issues a safety communication. Book a demo to see how Pabau keeps the screening, the dose, and the follow-up on one patient record.

Continue your research

Reconciling the patient’s full drug list first? Medication review gives you a structured format for catching interactions before you add another agent.

Documenting the abdominal exam that goes with it? Abdominal exam documentation sets out the findings worth recording when pain is part of the picture.

Recording the decision so it holds up on review? Safer clinical notes covers how to write up a recommendation, the reasoning, and the follow-up.

Collecting the history before the patient reaches the room? General practice intake gathers the symptom timeline your red-flag screening depends on.

Frequently asked questions