Diphenoxylate is an opioid drug used for the treatment of acute diarrhea. The drug is used in combination with atropine and marketed under names Lomotil and Diphenoxylate hydrochloride and atropine sulfate. Diphenoxylate is biotransformed in man by ester hydrolysis to diphenoxylic acid (difenoxine), which is biologically active and the major metabolite in the blood. The drug exerts its action by activating mu opioid receptors of intestinal mucosa.

Diphenoxylate:
https://drugs.ncats.io/drug/73312P173G

Lomotil is a combination of two drugs, diphenoxylate and atropine. It is used to treat acute diarrhea (diarrhea of limited duration). Diphenoxylate is a man-made narcotic chemically related to meperidine (Demerol). Like other narcotics, diphenoxylate reduces diarrhea by interfering with the propulsion of intestinal contents through the intestines. Although diphenoxylate is chemically related to narcotics, it does not have pain- relieving (analgesic) actions like most other narcotics. In higher doses, however, like other narcotics, diphenoxylate can cause euphoria (elevation of mood) and physical dependence.

In order to prevent abuse of diphenoxylate for its mood-elevating effects, atropine is combined with diphenoxylate in small quantities. As a result, if Lomotil is taken in greater than recommended doses unpleasant side effects from too much atropine will occur.

Excerpt from Medicinenet:
https://www.medicinenet.com/diphenoxylate_and_atropine/article.htm

Approved by the Food and Drug Administration in 1960 - President Kennedy and the Apollo Space Team reportedly used it - Lomotil comes in both liquid and pill form. (Lonox is another brand name for the same drug.) As the generic name suggests, Lomotil, which is manufactured by Pfizer, mixes two drugs: diphenoxylate, an antidiarrheal, and atropine, an anticholinergic. Diphenoxylate works by slowing down the internal movements of the bowels. Diphenoxylate is a narcotic, and a touch of atropine (0.025 milligrams), which in large doses can bring on nausea, was added to discourage deliberate overdosing on the combo pill.

Lomotil needs to be used with special caution in children younger than 2 years old, as overdosage can result in severe breathing problems and coma, which could end in permanent brain damage or death. Children are also more susceptible to atropine poisoning. Avoid consuming alcohol while taking Lomotil, as Lomotil will intensify the effects of alcohol and other medications that slow down the central nervous system, and augment the sedative effect of the drug. Not knowing what medical condition is causing the diarrhea, Lomotil may be used under the supervision of your health care provider. Lomotil can be used long-term, but dependency could be an issue.

Excerpt from Everyday Health:
https://www.everydayhealth.com/drugs/lomotil

Diphenoxylate and atropine combination is used along with other measures (eg, fluid and electrolyte treatment) to treat severe diarrhea. Diphenoxylate helps stop diarrhea by slowing down the movements of the intestines. Diphenoxylate is chemically related to some narcotics and may be habit-forming if taken in doses that are larger than prescribed. If higher than normal doses of the combination are taken, the atropine will cause unpleasant effects. This medicine is available only with your doctor's prescription.

In addition to using medicine for diarrhea, it is very important that you replace the fluid lost by the body and follow a proper diet. For the first 24 hours you should eat gelatin and drink plenty of caffeine-free clear liquids, such as ginger ale, decaffeinated cola, decaffeinated tea, and broth. During the next 24 hours you may eat bland foods, such as cooked cereals, bread, crackers, and applesauce. Fruits, vegetables, fried or spicy foods, bran, candy, caffeine, and alcoholic beverages may make the condition worse. The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label.

Excerpt from goodrx.com:
https://www.goodrx.com/diphenoxylate-atropine/what-is

What is the most important information I should know about atropine and diphenoxylate

• Do not use this medicine if you have diarrhea that is caused by bacteria or by taking an antibiotic.
• You should not use atropine and diphenoxylate if you have a bile duct disorder causing jaundice (yellowing of your skin or eyes).
• Keep this medicine where a child cannot reach it.
• An overdose can be fatal to a child.
• Atropine and diphenoxylate is not approved for use by anyone younger than 6 years old.
• This medicine has not been proven safe or effective in children younger than 13 years old.
• It is not known whether this medicine will harm an unborn baby. Tell your doctor if you are pregnant.

Excerpt from Healthwise:
https://www.uofmhealth.org/health-library/d03506a1

Breastfeeding:
Summary of Use During Lactation:
No data exist on the use of diphenoxylate during breastfeeding. One expert panel considers diphenoxylate to be unacceptable during breastfeeding.

Based on its chemical and pharmacological similarity to narcotics, occasional small doses of diphenoxylate may be acceptable while breastfeeding an older infant, but alternatives are preferred, especially while nursing a newborn.

Alternate Drugs to Consider:

• Loperamide

Diphenoxylate Drug Levels and Effects:
https://www.ncbi.nlm.nih.gov/books/NBK501330/

Lomotil (diphenoxylate and atropine)

Side Effects:
Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
RxList
Lomotil (diphenoxylate and atropine): https://www.rxlist.com/lomotil-drug/patient-images-side-effects.htm
Some side effects may occur up to 30 hours after you take this medicine.
Stop using this medicine and call your doctor at once if you have: severe constipation, stomach pain or bloating ongoing or worsening diarrhea diarrhea that is watery or bloody severe pain in your upper stomach spreading to your back fever, flushing (warmth, redness, or tingly feeling) hallucinations, seizure rapid breathing, weak or shallow breathing fast heart rate dehydration symptoms - feeling very thirsty or hot, being unable to urinate, heavy sweating, or hot and dry skin
Common side effects may include: drowsiness, dizziness, feeling restless headache numbness in your hands or feet depression, not feeling well confusion, feelings of extreme happiness red or swollen gums dry mouth, nose, or throat nausea, vomiting, upset stomach, loss of appetite skin rash, dryness, or itching
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Pediatric:
Appropriate studies performed to date have not demonstrated pediatric-specific problems that would limit the usefulness of diphenoxylate and atropine combination in children 13 years of age and older.

Safety and efficacy have not been established in children younger than 13 years of age.

This medicine should not be used in children younger than 6 years of age because of the risk for respiratory depression (severe breathing problem) or coma (loss of consciousness).

Geriatric:
No information is available on the relationship of age to the effects of diphenoxylate and atropine combination in geriatric patients.

Other Medical Problems:
Make sure you tell your doctor if you have any other medical problems, especially:

• Diarrhea caused by antibiotics or an infection, including sepsis
• Obstructive jaundice - Should not be used in patients with these conditions

• Down's syndrome - May cause side effects to become worse

• Enlarged prostrate
• Gallbladder disease
• Glaucoma
• Heart disease
• Hypertension (high blood pressure)
• Kidney disease
• Liver disease
• Myasthenia gravis (severe muscle weakness)
• Problems passing urine
• Stomach or bowel problems (eg, blockage, hiatal hernia, ulcerative colitis)
• Thyroid problems - Use with caution. May make these conditions worse

Diphenoxylate and Atropine (Oral Route) (Lomocot | Lomotil | Lonox | Vi-Atro):
https://www.mayoclinic.org/drugs-supplements/diphenoxylate-and-atropine-oral-route/description/drg-20061751

Liver:
Diphenoxylate has not been linked to serum enzyme elevations during therapy or to clinically apparent liver injury.

Diphenoxylate Hepatotoxicity:
As with most opiates in current use, therapy with diphenoxylate with atropine has not been linked to serum enzyme elevations. There have been no convincing cases of idiosyncratic acute, clinically apparent liver injury attributed to diphenoxylate. The reason for its lack of hepatotoxicity may relate partially to the low doses used. What diphenoxylate that is absorbed is metabolized in the liver.

Diphenoxylate Overview:
https://www.ncbi.nlm.nih.gov/books/NBK548367/

Lomotil (atropine sulfate / diphenoxylate hydrochloride)
Maximum Dosage

Maximum Dosage:
Prescribers Digital Reference
Lomotil - Drug Summary: https://www.pdr.net/drug-summary/Lomotil-atropine-sulfate-diphenoxylate-hydrochloride-1183
Adults:	20 mg/day PO.
Geriatric:	20 mg/day PO.
Adolescents:	20 mg/day PO.
Children:	6 to 12 years: Not recommended.
Children:	1 to 5 years: Do not use.
Infants:	Do not use.

FDA Lomotil CV (PDF 8 pages):
https://www.accessdata.fda.gov/drugsatfda_docs/label/2017/012462s045lbl.pdf

Lomotil Tablets Safety Prescribing Information:
https://www.pfizer.com/sites/default/files/products/material_safety_data/CLOTIAZEPAM%20TABLETS.pdf

Drugs.com Lomotil Tablets Package Leaflet:
https://www.drugs.com/uk/lomotil-2-5mg-0-025mg-tablets-leaflet.html

Kaiser Permanente Lomotil Oral Liquid:
https://healthy.kaiserpermanente.org/health-wellness/drug-encyclopedia/drug.diphenoxylate-atropine-2-5-mg-0-025-mg-5-ml-oral-liquid.294410?kpSearch=diphenoxylate-atropine

A meperidine congener used as an antidiarrheal, usually in combination with atropine. At high doses, it acts like morphine. Its unesterified metabolite difenoxin has similar properties and is used similarly. It has little or no pain relieving activity.