Digestive Health Diarrhea Side Effects of Lomotil (Lonox, Vi-Atro) This Drug Might Be Used To Treat Diarrhea From IBS Or Other Conditions By Amber J. Tresca Amber J. Tresca Facebook LinkedIn Twitter Amber J. Tresca is a freelance writer and speaker who covers digestive conditions, including IBD. She was diagnosed with ulcerative colitis at age 16. Learn about our editorial process Updated on November 12, 2022 Medically reviewed by Jay N. Yepuri, MD, MS Medically reviewed by Jay N. Yepuri, MD, MS Facebook LinkedIn Twitter Jay Yepuri, MD, MS, is a board-certified gastroenterologist and a practicing partner at Digestive Health Associates of Texas (DHAT). Learn about our Medical Expert Board Print What Is Lomotil? Lomotil (diphenoxylate hydrochloride; atropine sulfate) is a drug that slows down or stops diarrhea by slowing the contractions of the large intestine. Lomotil may be prescribed by a healthcare provider for the diarrhea associated with irritable bowel syndrome (IBS) or other digestive diseases or conditions. Lomotil is a controlled substance and is chemically related to a narcotic. Doble-d / Getty Images Warnings and Precautions When Using Lomotil Lomotil should not be used to treat antibiotic-associated diarrhea or diarrhea resulting from infectious bacteria, such as Escherichia coli, Salmonella, or Shigella. Diarrhea from these causes should be ruled out before Lomotil is prescribed. The reason is that because when diarrhea is caused by a bacteria, the bacteria needs to leave the body in order for a person to get better. A drug like Lomotil will prevent diarrhea and prolong the time the bacteria spends in the body. Lomotil should also only be used under the supervision of a healthcare provider by anyone who has liver disease or ulcerative colitis (due to a risk of a rare but serious condition called toxic megacolon). Taking Lomotil can increase the effects of barbiturates, tranquilizers, or alcohol, and can cause side effects such as sedation. Tell your healthcare provider if you are taking any other drugs while taking Lomotil, and you shouldn't drink alcohol while taking it. It should also not be taken at doses higher than what is prescribed because of the risk of addiction to diphenoxylate hydrochloride. Taking Lomotil as prescribed to treat diarrhea, however, will not result in addiction. Recommended Dosage of Lomotil It is very easy to become confused about dosage, especially when using the liquid formulation. That's why it is important to only use the dropper that comes with the medication, especially when giving Lomotil to children. Adults: A typical dose is two 2.5 mg tablets four times a day (for 20 mg a day) or 5 to 10 ml four times a day of the liquid formulation. When diarrhea slows down, which generally happens in about 48 hours, less Lomotil can be taken. Children: Don't give Lomotil to children under the age of 2. For older children, use the liquid, and only use this drug under the supervision of a medical professional. The dosage will vary by weight, so it's important that the child's weight is known and that a healthcare provider prescribes the correct amount. A dosing schedule is available in the Lomotil Prescribing Information, which is provided for reference only. Children with Down syndrome may be more prone to experience side effects as a result of the atropine component of Lomotil. Possible Side Effects of Lomotil Check with your healthcare provider if any of the following side effects continue or are bothersome: Blurred visionConfusionDifficult urinationDizziness or lightheadednessDrowsinessDryness of skin and mouthFeverHeadacheDepressionNumbness of hands or feetSkin rash or itchingSwelling of the gums Always Notify Healthcare Provider Call your healthcare provider if any of the following side effects are severe and occur suddenly, since they may be signs of a more severe and dangerous problem with your bowels. BloatingConstipationLoss of appetiteSevere stomach pain with nausea and vomiting Symptoms of an Overdose of Lomotil Blurred vision (continuing) or changes in near visionDrowsiness (severe)Dryness of mouth, nose, and throat (severe)Fast heartbeatShortness of breath or troubled breathing (severe)Unusual excitement, nervousness, restlessness, or irritabilityUnusual warmth, dryness, and flushing of the skin Other side effects not listed above may also occur in some patients. If there are any other effects, check with a healthcare provider. This information is meant only as a guideline. Always consult a practitioner or pharmacist for complete information about prescription medications. 1 Source Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Pfizer, Inc. Prescribing Information - Lomotil. Uodated Oct 2005. By Amber J. Tresca Amber J. Tresca is a freelance writer and speaker who covers digestive conditions, including IBD. She was diagnosed with ulcerative colitis at age 16. See Our Editorial Process Meet Our Medical Expert Board Share Feedback Was this page helpful? Thanks for your feedback! What is your feedback? Other Helpful Report an Error Submit