Loperamide (Imodium and others)

How Medicare covers it

Part D (capsules taken at home). Part A during a covered inpatient stay. No Part B clinician-administered form in the CMS Part B spending file.

What it treats

Control and symptomatic relief of acute nonspecific diarrhea in patients 2 years of age and older, and of chronic diarrhea in adults associated with inflammatory bowel disease. It is also used to reduce the volume of discharge from ileostomies.

What it is for, in depth

Loperamide is an antidiarrheal medicine used to control sudden, short-term diarrhea in people 2 years of age and older, when the diarrhea does not have a specific cause that needs its own treatment. In adults, it is also used for ongoing diarrhea linked to inflammatory bowel disease, where it is a symptom-control medicine used alongside treatment of the bowel condition itself. It is also prescribed to reduce the volume of discharge from an ileostomy, which helps people with an ostomy lose less fluid. The form in this package is the prescription 2 mg oral capsule, and treatment is meant to be short and dose-limited — if acute diarrhea does not improve within 48 hours, the label directs patients back to their healthcare provider.

How it works

Loperamide slows the movement of the bowel. It binds to opiate receptors in the gut wall, which reduces the release of acetylcholine and prostaglandins, slowing the pushing movements (peristalsis) and giving the bowel more time to absorb water. It also tightens the anal sphincter, reducing leakage and urgency, and it reduces daily stool volume and fluid and electrolyte loss.

How it is taken

The 2 mg capsules are taken by mouth exactly at the prescribed dose — never more than recommended. For acute diarrhea in adults, the usual first dose is 4 mg (two capsules), followed by 2 mg (one capsule) after each unformed stool, up to a maximum of 16 mg (eight capsules) per day; improvement is usually seen within 48 hours. For chronic diarrhea in adults, the same starting pattern is used until diarrhea is controlled, then the dose is lowered to the person's needs — the average maintenance dose in trials was 4 to 8 mg per day. Fluids and electrolytes should be replaced as needed while diarrhea continues.

Common side effects

In placebo-controlled studies, the side effect reported more often on loperamide than on placebo was constipation (2.6% in acute diarrhea studies and 5.3% in chronic diarrhea studies), and dizziness was also reported in chronic diarrhea studies (1.4%). Other effects reported include dry mouth, abdominal pain, cramps or discomfort, nausea, vomiting, gas, indigestion, tiredness, drowsiness, and urinary retention.

Serious warnings

Taking more than the recommended dose can cause dangerous heart rhythm problems — QT prolongation, Torsades de Pointes (a life-threatening rhythm), other ventricular arrhythmias, cardiac arrest, and death — and cases have also included abuse and misuse of the drug. Get help right away for fainting, a rapid or irregular heartbeat, or unresponsiveness. Loperamide must not be given to children under 2 years of age because of the risks of breathing depression and serious heart reactions. Stop the drug promptly if constipation, abdominal distention, or ileus (a blocked, stopped bowel) develops, because it can lead to megacolon and toxic megacolon; patients with AIDS should stop at the earliest signs of abdominal distention. Diarrhea also causes fluid and electrolyte loss, which must be treated alongside the drug.

Boxed warning

Boxed warning — Torsades de Pointes and sudden death: Cases of Torsades de Pointes, cardiac arrest, and death have been reported with the use of higher than recommended dosages of loperamide hydrochloride. Loperamide hydrochloride is contraindicated in pediatric patients less than 2 years of age, and dosages higher than recommended should be avoided in adults and pediatric patients 2 years of age and older due to the risk of serious cardiac adverse reactions.

Who should be careful

Children under 2 must not receive it, and children in general need special caution because their response varies more. Older patients may be more susceptible to effects on the QT interval and should avoid it if they take QT-prolonging drugs or have risk factors for Torsades de Pointes. People with a history of heart rhythm problems, congenital long QT syndrome, other heart conditions, or electrolyte abnormalities should avoid it or use it only with medical guidance. People with liver impairment should use it with caution because the body may be exposed to more of the drug. It should not be used when slowing the bowel must be avoided, and caution is needed when driving because tiredness, dizziness, or drowsiness may occur.

Major interactions

Drugs that block the CYP3A4 enzyme (such as itraconazole), the CYP2C8 enzyme (such as gemfibrozil), or P-glycoprotein (such as quinidine and ritonavir) can raise loperamide levels in the body — in one study, itraconazole plus gemfibrozil raised loperamide exposure 12.6-fold — increasing the risk of heart reactions. Avoid loperamide with other drugs known to prolong the QT interval, including Class IA antiarrhythmics (quinidine, procainamide), Class III antiarrhythmics (amiodarone, sotalol), antipsychotics (chlorpromazine, haloperidol, thioridazine, ziprasidone), the antibiotic moxifloxacin, pentamidine, and methadone. Loperamide can also lower exposure to saquinavir by 54%, which may reduce how well saquinavir works.

Cost and saving notes

Loperamide capsules taken at home are covered under Medicare Part D. If your plan's copay is high, you can ask the plan for a tier exception to move the drug to a lower-cost tier. If you have limited income, Extra Help (the Low Income Subsidy) can lower Part D premiums and drug costs. In 2027, total yearly out-of-pocket Part D drug spending is capped at $2,400, and the Medicare Prescription Payment Plan lets you spread your drug costs into monthly payments instead of paying large amounts at the pharmacy.

Why it is in its tier

Loperamide sits on Tier 2 in 87.14% of the Part D plans that list it, and 97.96% of Part D plans list it (5,383 of 5,495 plans in the 2027 CMS data). Tier 2 is usually a preferred generic tier, so patients typically pay a modest flat copay rather than a percentage of the cost. That placement matches the data behind it: this is a single low-cost generic capsule form, and the CMS dashboard average spending was the lowest in this group — about $39 per beneficiary and about $19 per claim in 2024. Individual plans vary, so check your own plan's drug list for your exact tier and copay.

Sources

• LOPERAMIDE HYDROCHLORIDE CAPSULE [NUCARE PHARMACEUTICALS,INC.] — DailyMed
• MedlinePlus — National Library of Medicine
• MedlinePlus — Loperamide

What official patient guides say

Loperamide comes as a tablet, capsule, and suspension or solution to take by mouth; nonprescription loperamide is usually taken immediately after each loose bowel movement, but not more than the 24-hour maximum described on the label. If you take the liquid, do not use a household spoon — use the measuring cup that came with the medication or a spoon made for measuring liquid medication. If you take scheduled doses and forget one, take it as soon as you remember, but if it is almost time for the next dose, skip the missed dose and do not take a double dose. Keep it in the container it came in, tightly closed and out of reach of children, stored at room temperature away from excess heat and moisture, not in the bathroom.

Source: MedlinePlus — Loperamide

Part D formulary coverage

Source: CMS Prescription Drug Plan Formulary, Pharmacy Network, and Pricing Information Files — Monthly file 2026-10-15 (plan year 2027), file 2027_20261008.zip (data.cms.gov dataset ed1496ea-23e7-41f1-9292-172fa842ccfb): basic drugs formulary file + plan information file, both dated 20261031 inside the zip; downloaded and aggregated 2026-10-30. Medication RxCUI sets resolved through the NLM RxNav (RxNorm) API.

What you pay

Without insurance, the cash benchmark is 0.05777 per unit (LOPERAMIDE 2 MG CAPSULE) — about nan for 30 units. NADAC benchmark — the average price pharmacies pay (CMS, as of 2026-11-04). Pharmacy shelf prices vary.

A tier is not a price; what you pay depends on your plan, pharmacy, and benefit stage; Extra Help or Medicaid can lower it further.

Sources: CMS Plan Benefit Package + formulary data; CMS NADAC · Checked 2026-11-07

Coverage by plan and tier

Of the 5,495 Medicare drug plans we track for 2027, 5,383 list Loperamide (Imodium and others) — 98.0% of plans. Most of those plans put it on Tier 2: 4,691 plans, 87.1% of the plans that list it. Other plans place it on Tier 1 (502 plans) or Tier 3 (190 plans). For example: Aetna Medicare Dual Extra (HMO D-SNP) puts it on Tier 2; Aetna Medicare Dual Extra Care (PPO D-SNP) puts it on Tier 2; Aetna Medicare Value Plus (PPO) puts it on Tier 2. You can compare these plans side by side on our Medicare Advantage hub. A tier is not a price. What you pay also depends on whether you have met your plan';s deductible, whether the drug costs a flat copay or a share of the price, and whether you get Extra Help or Medicaid.

Read next

• Part D in 2027: The $700 Deductible, the $2,400 Cap, and the $35 Insulin Rule
• Extra Help in 2027: Lower Drug Copays and Who Qualifies
• Checking Medicare Savings Programs and Extra Help

Part D spending averages (2024)

Source: CMS Medicare Part D Spending by Drug (Drug Spending Dashboard), release RY26 P04 V10, data through 2024 (DSD_PTD_RY26_P04_V10_DY24_BGM.csv), downloaded 2026-10-30

Companies covering this drug

Part D and Medicare Advantage plan sponsors that list this drug on a formulary, 50 at a time.