Compare Imodium vs. Rolaids

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


(Calcium Carbonate / Magnesium Hydroxide)

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 and acid tummy. Rolaids (Calcium Carbonate / Magnesium Hydroxide) gives quick relief for heartburn, but don't expect it to last all day.
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Reviews & ratings
Button Group. All currently active
Button Group. All currently active
Reviews for Imodium (Loperamide)
of people say Imodium (Loperamide) is worth it
say it works well
say it's a big hassle
Reviews for Rolaids (Calcium Carbonate / Magnesium Hydroxide)
14% vs. Imodium (Loperamide)
27% 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 »

We haven’t found good data for Rolaids side effects.

FDA side effect reports for Rolaids »
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.Rolaids (Calcium Carbonate / Magnesium Hydroxide) is an antacid. It counteracts the effects of stomach acid to relieve heartburn and acid tummy (indigestion).
Type of medication
Available as
  • Pill
  • Chewable tablet
  • Liquid
  • Chewable tablet
  • Liquid
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 disease
    • Kidney dialysis
    • Hyperparathyroid disease
    • Taking high doses of Vitamin D
    • Previous kidney stones
    Detailed Rolaids (Calcium Carbonate / Magnesium Hydroxide) 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
    NFDA pregnancy category (Unknown)

    The FDA hasn’t classified this medicine’s effects on unborn babies. Talk with your doctor about this medicine if you’re pregnant or planning on it.

    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 on dialysis may need to take a lower dose or avoid use. Your doctor can do blood tests to see if it's safe to use.
    • If you have kidney or hyperparathyroid disease Rolaids (Calcium Carbonate / Magnesium Hydroxide) can build up in your blood. This may can cause toxic levels of calcium in your body. This is more likely if you have severe kidney disease (defined as a kidney function blood test called GFR of less than 30ml/min). If you have severe kidney disease or are on kidney dialysis don't use Rolaids (Calcium Carbonate / Magnesium Hydroxide); a different antacid would be better for you.
    • Rolaids (Calcium Carbonate / Magnesium Hydroxide) contains calcium. Calcium can be an ingredient in some kidney stones. If you have had kidney stones in the past (especially the calcium-containing kind) be careful using Rolaids (Calcium Carbonate / Magnesium Hydroxide). Use the lowest dose for the shortest time possible or just play it safe and use a different antacid instead.
    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.
    • Works really fast.
    • Available over the counter without a prescription.
    • Cheap.
    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.
    • Doesn't last very long.
    • Other antacids like Zantac (H2 blockers) and omeprazole (proton pump inhibitors) can work better and last longer.
    • Some chalky aftertaste.
    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.
    • Take at the first sign of discomfort.
    • You might need to take more than once a day but pay attention to the instructions on your bottle to avoid overdosing.
    • Take 1-2 hours apart from other medication that you take by mouth.
    • If heartburn doesn't improve or lasts more than 2 weeks, talk to your doctor.
    • People with kidney disease on dialysis may need to take a lower dose or avoid use. Your doctor can do blood tests to see if it's safe to use.
    • Don't take if you have high blood calcium levels.
    Learn more
    More about ImodiumSide effectsReviews & ratingsAlternativesFDA package insert
    More about RolaidsSide effectsReviews & ratingsAlternativesFDA package insert