Imodium (Loperamide) at a glance: schedule, half-life, and class
- Generic name
- Loperamide hydrochloride
- Brand names
- Imodium A-D, Imodium Multi-Symptom Relief
- Drug class
- Peripheral opioid receptor agonist
- US legal status
- Over the counter; not controlled
- Approved uses
- Diarrhea, including travelers' diarrhea
- Forms
- Capsules, tablets, liquid
- Maximum OTC dose
- 8 mg a day for adults
- Half-life
- About 9 to 14 hours
- Packaging limits
- Sold in blister packs of limited size since 2019 to deter misuse
Imodium uses: what loperamide is prescribed for
Loperamide slows the movement of the gut and treats diarrhea. At normal doses a transporter called P-glycoprotein pumps it out of the brain, so it has no opioid effects on mood or breathing.[1]
Some people take tens or hundreds of times the label dose to self-treat opioid withdrawal or to get high. The FDA warned in 2016 that such doses had caused serious heart problems and deaths, and asked makers to limit package sizes.[2]
How much loperamide is safe to take?
These directions come from the over-the-counter Drug Facts label. Do not use for more than 2 days without talking to a clinician.[1]
| Product or group | Label directions | Notes |
|---|---|---|
| Adults and children 12 and over | 4 mg after the first loose stool, then 2 mg after each later loose stool | No more than 8 mg in 24 hours |
| Children 6 to 11 | Weight-based dosing on the package | Ask a clinician for children under 6 |
| Bloody stool or fever | Do not use | May signal an infection that needs medical care |
Imodium (loperamide) side effects and risks
Common side effects at label doses include constipation, dizziness, and stomach cramps.[1]
Heart rhythm problems: high doses lengthen the heart's QT interval and widen the QRS complex, causing fainting, torsades de pointes, ventricular tachycardia, and cardiac arrest. These can be hard to treat and deaths have occurred.[2]
Children: in young children, even modest overdoses can cause severe constipation, drowsiness, and slowed breathing.
Warning: Taking more than the label dose to manage opioid withdrawal is dangerous. Buprenorphine and methadone treat withdrawal and opioid use disorder safely.
Imodium interactions: what not to mix with loperamide
Choose what it would be combined with:
| Combined with | What happens | Guidance |
|---|---|---|
| Methadone, antiarrhythmics, some antibiotics and antipsychotics | Stacked QT prolongation and heart rhythm risk | Avoid at high doses |
| Itraconazole, ketoconazole, clarithromycin, ritonavir, quinidine, gemfibrozil | Raise loperamide levels several-fold | Avoid combining with high doses |
| Cimetidine and P-glycoprotein inhibitors used to boost effects | Loperamide enters the brain; toxicity | Dangerous |
| Opioids | Constipation and, with misuse, sedation | Use caution |
This is not a full list. A pharmacist can check a complete medication list, including supplements and over-the-counter products.[1]
Imodium overdose: signs of loperamide overdose and what to do
Loperamide overdose can cause fainting, a fast or irregular heartbeat, seizures, and cardiac arrest, sometimes days after the last dose. It can also cause sleepiness and slowed breathing.[2]
If someone may have taken too much
- Call 911 for fainting, a seizure, chest pain, a racing or irregular heartbeat, confusion, or if the person cannot be woken.
- If the person collapses and is not breathing normally, start CPR and use an AED if one is available.
- Give naloxone if opioids could be involved. It is safe even if they are not.
- For advice when the person is awake and stable, call Poison Help at 1-800-222-1222 (US, free, 24 hours). Bring the product packaging to the hospital.
Imodium withdrawal timeline: how long loperamide withdrawal lasts
People who take very high doses every day develop opioid-like dependence and withdrawal when they stop.[2]
- 12 to 48 hoursEarly symptomsAnxiety, sweating, runny nose, yawning, muscle aches, and diarrhea.
- Days 2 to 5PeakStomach cramps, nausea, goosebumps, poor sleep, and cravings.
- 1 to 2 weeksLingering symptomsLow mood and cravings may persist.
Buprenorphine or methadone can treat underlying opioid use disorder. Heart monitoring may be needed during treatment of high-dose loperamide use.
How do you buy loperamide safely in the US?
Loperamide is sold over the counter without a prescription. Since 2019, the FDA has asked makers to sell it in blister packs with a limited number of doses to make misuse harder.[2]
- Cost: generic loperamide is inexpensive at pharmacies and grocery stores.
- Prescription strengths: clinicians can prescribe it for chronic diarrhea, with a maximum of 16 mg a day.
- Ask a pharmacist: a pharmacist can check whether it is safe with your other medicines and health conditions.
Can you buy loperamide online?
Yes. Loperamide is sold online by regular retailers. Buy from established pharmacies and stores, and follow the Drug Facts label.
The FDA's BeSafeRx tool explains how to recognize a safe online pharmacy.[3]
Is Imodium legal? Loperamide legal status in other countries
| Country | Status |
|---|---|
| United Kingdom | Pharmacy and general sale medicine, with pack-size limits |
| Canada | Non-prescription medicine |
| International | Not under UN control |
Laws change and differ in detail. Check current rules before carrying any controlled medicine across a border.[4]
Common questions about Imodium (loperamide)
Is Imodium an opioid?
Yes, chemically, but at label doses it stays in the gut and does not affect the brain or breathing.
How much Imodium (loperamide) is too much?
More than 8 mg a day without medical advice. Heart problems have been reported at doses of roughly 70 mg a day and higher.
Can Imodium (loperamide) help opioid withdrawal?
Label doses can ease diarrhea from withdrawal, but taking large amounts to relieve other symptoms is dangerous. Buprenorphine and methadone are safer and effective.
Does Imodium (loperamide) show up on a drug test?
Not on standard opioid screens.
Why do pharmacies sell Imodium in small packs?
The FDA asked makers to limit package sizes in 2019 to reduce misuse at very high doses.
Sources
- Imodium (loperamide) prescription information. DailyMed, US National Library of Medicine.
- FDA Drug Safety Communication: FDA warns about serious heart problems with high doses of the antidiarrheal medicine loperamide (Imodium). US Food and Drug Administration, 2016.
- BeSafeRx: Your Source for Online Pharmacy Information. US Food and Drug Administration.
- International drug control conventions. United Nations Office on Drugs and Crime.
