Compare Imodium vs. Zantac

Head-to-head comparisons of medication uses, side effects, ratings, and more.


Zantac 75

Treats diarrhea. One day is too many days to have diarrhea. Having Imodium (Loperamide) on hand to relieve your symptoms can be a life-saver.Relieves heartburn. Zantac 75 (Ranitidine) works well for heartburn but may not last as long or start working as quickly as other antacids.
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Reviews & ratings
Button Group. All currently active
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Reviews for Imodium (Loperamide)
of people say Imodium (Loperamide) is worth it
say it works well
say it's a big hassle
Reviews for Zantac 75 (Ranitidine)
17% vs. Imodium (Loperamide)
21% vs. Imodium (Loperamide)
1% vs. Imodium (Loperamide)
Side effects

The Imodium FDA package insert doesn’t have numbers about how common side effects are.

More about Imodium side effects »

The Zantac FDA package insert doesn’t have numbers about how common side effects are.

More about Zantac side effects »
How it works
Imodium (Loperamide) is an antidiarrheal medicine. It's actually an opioid related to morphine, though it doesn't affect the brain like opioid pain medicines do. Instead, it works directly on muscles in your large intestine to stop contractions and increase the time it takes for stool to move through. The result is less diarrhea and more formed stool.Zantac 75 (Ranitidine) is an H2 blocker. It blocks the chemical histamine, which lowers acid production in your stomach. This treats heartburn and helps ulcers heal.
Type of medication
Acid reducer
Histamine blocker
Prescription or OTC
Available as
  • Pill
  • Chewable tablet
  • Liquid
  • Pill
  • Oral solution
  • Injection
Used for (click to learn more)
Risk factors for serious side effects
  • Allergy to loperamide
  • Taking with alcohol
  • Taking other medicines that make you less alert
  • Current liver problems
  • Taking HIV medicines
  • Active infectious colitis
  • Women of childbearing age
Detailed Imodium (Loperamide) risks & warnings »
    • Current kidney problems
    • Current liver problems
    • Acute Porphyria
    • History of Phenylketonuria (PKU)
    Detailed Zantac 75 (Ranitidine) risks & warnings »
    Pregnancy category
    CFDA pregnancy category (Weigh risks vs. benefits)

    Research studies with animals found harmful effects on unborn babies. It hasn’t been properly studied in humans. The benefits might outweigh the risks even if you’re pregnant. Talk with your doctor.

    See the FDA package insert
    BFDA pregnancy category (Probably safe)

    Research studies with animals haven’t found a risk to unborn babies, but it hasn’t been properly studied in humans.

    See the FDA package insert
    No specific alcohol-related info.No specific alcohol-related info.
    No specific food-related info.No specific food-related info.
    Kidneys and liver
    No specific kidneys and liver-related info.
    • People with kidney disease may need to take a lower dose.
    • Zantac 75 (Ranitidine) is processed by the kidney and liver. If you have kidney or liver problems, you may need a different dose to prevent this increased risk for side effects.
    No specific sex-related info.No specific sex-related info.
    No specific sleep-related info.No specific sleep-related info.
    • The correct dose of Imodium may be different depending on age. Use the dosing chart to find the right amount of medicine based on age and weight.
    No specific weight-related info.
    Upsides and benefits
    • Most people who take Imodium feel there's no hassle and it's definitely worth it!
    • Non-habit forming and available over-the-counter.
    • It comes in caplets, liquid, and chewable tablets so you can use it anywhere you need it.
    • Imodium is used for short-term, chronic and traveler's diarrhea. It's also used for people who have diarrhea caused by cancer or certain medicines that treat cancer.
    • Most people can take Ranitidine without any noticeable day-to-day side effects.
    • Ranitidine lasts longer than many other antacids like Maalox and Tums, and you only need to take it once or twice a day.
    • You can take it in combination with a quick-acting antacid (like Maalox or Tums) if you need relief right away.
    • Available as both a generic and over-the-counter option, so it's pretty affordable.
    • Few drug interactions.
    Downsides and risks
    • Imodium only treats your diarrhea symptoms. Diarrhea may be caused by a number of conditions and will need specific treatment that deals with the underlying issue.
    • Studies in people taking Imodium for chronic diarrhea showed if the maximum number of doses didn't relieve symptoms in 10 days, then it probably won't work for that condition. You can talk to your doctor about other treatment options.
    • Other antacids like Maalox, Tums, or Rolaids often start to work more quickly than Ranitidine.
    • Medication like omeprazole (proton pump inhibitors) works better at healing and preventing stomach ulcers than medication like Ranitidine (H2 blockers).
    Tips from our pharmacists for people taking the medication
    • Try to drink plenty of clear liquids. Having diarrhea can make you dehydrated.
    • The correct dose of Imodium may be different depending on age. Use the dosing chart to find the right amount of medicine based on age and weight.
    • Shake Imodium liquid well before using. Use dosing cup that comes with bottle to get the best dose.
    • Imodium lowers your ability to focus, think, and react. Avoid activities that require you to be alert, such as driving a car or operating machinery, until you know how this medication affects you.
    • Check with your baby doctor before using if you're breastfeeding.
    • Ask your doctor before taking Imodium if you have a fever, liver problems, mucus in your stool or are taking antibiotics.
    • Don't use if you have blood in your stool or it's dark or black in color.
    • Stop using Imodium and call your doctor if you have pain, swelling or bulging in your belly or your symptoms get worse after 2 days. This could be serious.
    • Works best if you take it with a full glass of water.
    • Starts working in one hour.
    • If heartburn doesn't improve or lasts more than 2 weeks, talk to your doctor.
    • People with kidney disease may need to take a lower dose.
    Learn more
    More about ImodiumSide effectsReviews & ratingsAlternativesFDA package insert
    More about ZantacSide effectsReviews & ratingsAlternativesFDA package insert