Loperamide

Last Reviewed: Nov 14, 2024

Warnings

Loperamide Risks, Warnings, and Complications

Loperamide can cause or worsen health problems in certain people. Talk to your doctor or pharmacist about other treatment options for diarrhea if you are at increased risk of adverse reactions from this drug. Some of the risks of taking loperamide include:

LIFE-THREATENING HEART RHYTHM PROBLEMS: There are reports of serious, potentially life-threatening heart rhythm problems in people who took high doses (more than the recommended dosages) of loperamide. The risk for heart problems is higher in people with pre-existing conditions such as long QT syndrome, slow or irregular heartbeat, and hypokalemia (low potassium), as well as those taking other medications that can affect the heart rhythm.
Do not give loperamide to children younger than 2 years of age. Do not take more than the recommended dose of this antidiarrheal medication. Tell your doctor immediately or seek emergency medical attention if you develop a fast, pounding, or irregular heartbeat, severe dizziness, or fainting after taking loperamide.
BLOATING AND CONSTIPATION: Loperamide slows down movements in the bowels and can cause gas, bloating, and constipation. Call your doctor if you develop stomach pain or constipation after loperamide use.
SEVERE ALLERGIC REACTION: Rarely, loperamide can cause a life-threatening hypersensitivity reaction. Seek emergency medical help if you develop swelling of your face, eyes, lips, tongue, or throat, skin rash, hives, itching, or difficulty breathing.
LOPERAMIDE MISUSE: Loperamide acts on opioid receptors in the body, similar to opioid drugs. For this reason, it is sometimes called a poor man’s methadone. High-dose loperamide abuse has been reported for recreational use. Some people engaging in loperamide abuse take this medicine with other drugs called P-glycoprotein inhibitors, such as quinine. This allows loperamide to cross the blood-brain barrier and increase its euphoric effects. Improper use is also undertaken to lessen symptoms of opioid withdrawal.
However, these are extremely dangerous practices. Loperamide toxicity can cause life-threatening health complications, including respiratory depression (slowed breathing), heart rhythm abnormalities such as Torsades de Pointes and other ventricular arrhythmias, cardiac arrest, and sudden cardiac death.

Precautions Before Starting Loperamide

Tell your doctor if you have ever had an allergic reaction to loperamide, any of the active or inactive ingredients in loperamide formulations, other antidiarrheal drugs, or any other medications. Your pharmacy can give you a list of ingredients.

Give your doctor and pharmacist a complete list of your medications, including prescription drugs, over-the-counter medicines, vitamins, supplements, and herbal products. This can help avoid interactions between your medications and prevent cardiac arrhythmias and other serious complications.

Give your doctor a complete medical history. Loperamide may not be safe for people with certain medical conditions such as cardiac dysrhythmia, colitis, ulcerative colitis, liver disease, Addison’s disease, or acquired immunodeficiency syndrome (AIDS). Also, tell your doctor if you have blood or mucus in stool, stomach pain without loose stools, fever, or black tarry stools.

Tell your doctor if you are pregnant, might be pregnant, planning a pregnancy soon, or breastfeeding.

Precautions During Use of Loperamide

Call your doctor if your diarrhea does not improve after 2 days or gets worse after taking over-the-counter loperamide.

Drink plenty of water and stay well hydrated.

Loperamide can make you dizzy and drowsy. Do not drive or operate machinery until you know how you feel on this medicine.

Tell all your healthcare providers you are on loperamide, including before dental treatments.

Call your doctor if you become pregnant while taking loperamide.

Loperamide Drug Interactions

Interactions between loperamide and many drugs can affect how the medicines work. Drug-drug interactions can also increase the risk of serious adverse events. Your doctor may change your dose, switch you to a different medication, and/or monitor you closely for adverse effects if there are known interactions between loperamide and your other medicines.

You should not take loperamide if you are on the following drugs:

Medications used to treat abnormal heart rhythms, such as amiodarone (Nexterone, Pacerone), procainamide, sotalol (Betapace, Betapace AF), quinidine (in Nuedexta)
Antipsychotic drugs such as chlorpromazine, thioridazine, haloperidol (Haldol), and ziprasidone (Geodon)
Opioid drugs such as methadone (Methadose, Dolophine)
Antibiotics such as moxifloxacin (Avelox)
Anti-infective agents such as pentamidine (Nebupent, Pentam)

The following medications can also interact with loperamide:

Antibiotics such as erythromycin (Eryc, E.E.S., Ery-Tab) and clarithromycin (Biaxin, in PrevPac)
Antifungal agents such as itraconazole (Onmel, Sporanox) and ketoconazole
Antimalarials such as quinine (Qualaquin)
H2 blockers such as cimetidine (Tagamet) and ranitidine (Zantac)
Cholesterol-lowering drugs such as gemfibrozil (Lopid)
HIV medications such as ritonavir (Norvir, in Kaletra) and saquinavir (Invirase)

The above list does not include all the possible interactions of loperamide. Give your healthcare professional a complete list of your medications, including prescription drugs, over-the-counter medications, dietary supplements, and herbal remedies. Also, tell your doctor or pharmacist if you smoke, drink alcohol, or use recreational drugs because some of these substances can cause serious health complications when used with over-the-counter and prescription medications.

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