Diphenoxylate and atropine (Lomotil®)
Pronounce: dye-fen-OKS-i-late & A-troe-peen
Classification: Antidiarrheal
About Diphenoxylate and atropine (Lomotil®)
Diphenoxylate and atropine is a medication (made up of two drugs) used to treat diarrhea (loose stools). It is used along with other medications to control diarrhea. This medication works by slowing the movement of the bowel and by preventing spasms in the muscles of the gut. If your cancer treatment is causing diarrhea, your provider may prescribe diphenoxylate and atropine to help manage it.
How to Take This Medication
Diphenoxylate and atropine come in tablet form and a liquid solution to be taken orally (by mouth). The dose and how often you take this medication depends on your treatment and how bad your diarrhea is. Ask your provider what your dose will be and how often you should take the medication.
It is important to make sure you are taking the correct amount of medication every time. Before every dose, check that what you are taking matches what you have been prescribed. One part of this medication, diphenoxylate, is chemically similar to a narcotic medication (meperidine). The amount of diphenoxylate in this medication is so low that it does not have the same effects as a narcotic and does not produce addiction. But, if overdosage happens or this medication is misused, the effects could be similar to an overdose of a narcotic/opioid. Symptoms of an overdose include difficult or shallow breathing, coma, and lethargy. DO NOT share this medication or give it to someone else, as severe breathing problems and death can occur. This medication should not be given to children less than 6 years of age, as cases of severe respiratory depression and coma can occur.
Don't drink alcohol while taking this medication. You should not drive a car or operate heavy machinery until you know how this medication affects you.
You should not take this medication if you have a fever or if your stool has mucus or blood in it, or if your stool is black without first talking with your provider. You may need to have your stool tested for certain infections, so you should tell your provider that you are having diarrhea prior to taking this medication.
Be sure to tell your provider about all medications and supplements you take. This medication can interact with other medications and supplements, including barbiturates, benzodiazepines, opioids, buspirone, antihistamines, muscle relaxants, benztropine, glycopyrrolate, hyoscyamine, and monoamine oxidase inhibitors (MAOIs).
Tell your provider if you have ever had problems with your bowels, including diarrhea associated with pseudomembranous enterocolitis (caused by Clostridium difficile) or other enterotoxin-producing bacteria, or if you have ulcerative colitis. Tell your provider if you have or ever had problems with your kidneys or liver.
Storage and Handling
Store this medication in the original container. For tablets, store them at room temperature (below 77°F [25°C]). For liquid solution, store in the original bottle at room temperature. Always use the provided oral syringe for the oral solution. Discard any medication left in an open bottle after 90 days. Keep this medication out of reach of children and pets. Dispose of any unused medication safely.
Where Do I Get This Medication?
Some cancer medications are only available through specialty pharmacies. Your provider or pharmacist will start this process. Your insurance plan may also affect where you can get your medication. Call your prescription plan provider to find out which specialty pharmacies are in-network.
Insurance Information
This medication may be covered by your prescription plan. If you qualify, you may be able to get financial help through patient assistance programs (PAP). Co-pay cards may also be available to lower your out-of-pocket cost if you have commercial (not Medicare/Medicaid/Tricare) insurance. Your pharmacist, social worker, or navigator can help find resources for financial support.
Possible Side Effects
These are some of the most common or most serious side effects of this medication. Talk with your provider about the side effects you are having and how they can be managed.
Central Nervous System (CNS) Effects
This medication may cause drowsiness, fatigue, sedation, dizziness, and weakness. If these effects make it hard to do your normal daily activities, talk with your provider.
Constipation and Belly Cramps
Constipation is when you have less bowel movements than usual or are having trouble passing stool. This medication can cause constipation and abdominal (belly) cramps. If you are having these side effects, tell your provider.
Reproductive Concerns
Talk to your provider before becoming pregnant, getting someone else pregnant, or breastfeeding while receiving this medication.
Dehydration and Electrolyte Changes
This medication can affect the normal levels of fluid and electrolytes (potassium, magnesium, calcium, etc.) in your body. Your providers will use blood tests to make sure these levels aren’t too high or too low.
If your levels become too low, there are certain electrolytes or fluids your provider can give you by IV or that you can take by mouth. Tell your provider before taking any supplements.
Toxic Megacolon
Toxic megacolon is when your colon swells and toxins go into your bloodstream. This is a serious condition. If you have ulcerative colitis (UC), this medication can raise your risk of toxic megacolon. Symptoms of toxic megacolon can be pain, bloating, or tenderness of your abdomen (belly), fever, fast heart rate (tachycardia), bloody diarrhea, and painful bowel movements.
Atropinism
Atropinism (also called atropine poisoning) happens when this medication is abused or overused. This medication has a subtherapeutic (very small) amount of atropine in it, and could cause these symptoms if it is not taken as prescribed:
- Hyperthermia (body temperature becomes too high).
- Tachycardia (fast heart rate).
- Urinary retention (unable to pee).
- Flushing and dryness of your skin and mucous membranes (tissue inside your body).