Loperamide

Acute nonspecific diarrhea at age ≥ 2; adult chronic diarrhea associated with inflammatory bowel disease; reduction of ileostomy discharge. Acute ulcerative colitis and invasive/inflammatory infections listed as contraindications remain excluded. This is not permission to suppress every diarrheal illness.

Selected OTC products control diarrhea symptoms, including travelers’ diarrhea. IDSA permits consideration in hydrated immunocompetent adults with watery diarrhea, but advises against use below age 18 with acute diarrhea and avoidance at any age with fever/inflammatory disease risking toxic megacolon. This guideline advice differs from age-based labeling; pediatric label tables are retained as provenance, not an infectious-diarrhea recommendation.

Acute diarrhea, adults and label ages ≥ 13: 4 mg initially, then 2 mg after each unformed stool; maximum 16 mg daily. Stop and obtain clinical review if acute symptoms fail to improve within 48 hours. Adult chronic diarrhea: the same initial stool-based regimen, then individualize maintenance as one/divided daily doses; trial average 4–8 mg daily, maximum 16 mg. Lack of response after at least 10 days at 16 mg makes further benefit unlikely. Ileostomy output requires a clinician-directed plan; no separate universal output-dose algorithm is provided.

Selected 2 mg softgels at age ≥ 12: 4 mg after the first loose stool, then 2 mg after each subsequent loose stool, maximum 8 mg in 24 hours; do not use this softgel product below 12. Selected liquid is 1 mg per 7.5 mL: age ≥ 12, 30 mL initially then 15 mL after each later loose stool, maximum 60 mL (8 mg) in 24 hours. Stop self-treatment if diarrhea lasts over 2 days, worsens or the abdomen swells.

IDSA advises against loperamide for acute diarrhea below 18. Prescription first-day age/weight bands below are label provenance requiring clinician assessment; ages 2–5 use an appropriate liquid. After day 1 the prescription label gives 1 mg per 10 kg only after a loose stool, with no more than the first-day maximum. Its overlapping age-8 wording and formulation needs require clinician clarification rather than automated dose selection. Pediatric chronic-diarrhea dosing is not established.

For 1 mg per 7.5 mL liquid only: ages 9–11 (60–95 lb), 15 mL initially then 7.5 mL after later loose stools, maximum 45 mL daily; ages 6–8 (48–59 lb), the same initial/subsequent volumes, maximum 30 mL daily. Prefer weight when possible; ages 2–5 (34–47 lb) ask a doctor; below 2 do not use. These label directions do not override the IDSA acute-diarrhea pediatric avoidance. Shake and use the enclosed product-specific cup. The prescription label mentions 1 mg per 5 mL liquid; do not apply that concentration to this current 1 mg per 7.5 mL product.

Replace fluids/electrolytes, assess the underlying cause and stop when diarrhea is controlled rather than routinely escalating. Renal impairment needs no labeled dose adjustment despite absent dedicated PK studies. Hepatic impairment requires caution and close CNS-toxicity monitoring because metabolism may be reduced; no validated numeric adjustment is supplied. Older patients need no age-only adjustment but have greater QT-risk susceptibility.

Age < 2; allergy to loperamide/ingredients; abdominal pain without diarrhea; acute dysentery with blood/high fever; acute ulcerative colitis; invasive bacterial enterocolitis such as Salmonella, Shigella or Campylobacter; antibiotic-associated pseudomembranous colitis. OTC labels additionally prohibit bloody/black stool and the selected softgel prohibits use below 12; fever/mucus require medical advice.

• Check product-specific OTC age restrictions and warning language before self-treatment.

Selected prescription capsules carry a boxed warning about torsades and sudden death with higher-than-recommended doses and contraindication below age 2. Selected OTC Drug Facts have a prominent heart alert rather than that prescription boxed format. Neither presentation permits exceeding directions.

Constipation, nausea, cramps, dizziness, drowsiness and tiredness occur; some overlap with diarrhea itself. Important reports include urinary retention, ileus/megacolon, severe allergy and serious skin reactions, as well as cardiac toxicity. Overdose can cause arrhythmias, CNS/respiratory depression and prolonged recurrent toxicity; seek emergency/Poison Help care (1-800-222-1222). Naloxone may reverse opioid effects but does not replace hospital cardiac management; ordinary opioid screens may miss loperamide. It is not a controlled substance, but abuse/misuse is documented.

CYP3A4 inhibitors such as itraconazole, CYP2C8 inhibitors such as gemfibrozil and P-glycoprotein inhibitors such as quinidine/ritonavir increase exposure and cardiac/CNS risk. Multiple inhibitors can compound the increase; do not invent a universal reduced dose. Avoid drugs known to prolong QT, including selected antiarrhythmics, antipsychotics and antibiotics; review prescription, OTC and herbal agents.

Loperamide reduced saquinavir exposure in a studied single-dose combination; monitor saquinavir therapeutic efficacy if coadministered. Never use interaction “boosters” or excessive loperamide for euphoria/opioid withdrawal. These uses can be fatal and require appropriate addiction/withdrawal care.

Below 2 is contraindicated; pediatric chronic-diarrhea safety/effectiveness and dose are unestablished. IDSA advises no loperamide for acute diarrhea in children below 18. Older adults may be more vulnerable to QT effects, interacting drugs and electrolyte loss; no age-only dose adjustment removes these risks.

No adequate controlled pregnancy studies; use only when potential benefit justifies fetal risk. Small amounts may enter human milk; the selected prescription label does not recommend use while breastfeeding. OTC wording asks patients to consult a health professional and does not establish pregnancy/lactation safety.

No renal adjustment is specified, with unchanged drug/metabolites mostly eliminated in feces. Hepatic PK is unstudied; reduced metabolism can increase exposure and CNS toxicity, so use cautiously and monitor closely. Do not extrapolate a safe overdose threshold or dialysis-clearance strategy.

Gut opioid-receptor binding reduces propulsive peristalsis and increases transit time/anal-sphincter tone, reducing stool volume and urgency. Capsule peak occurs about 5 hours versus 2.5 hours for liquid; protein binding about 95%, apparent half-life about 10.8 hours. CYP3A4/CYP2C8 oxidative metabolism and P-glycoprotein transport limit usual exposure; fecal elimination predominates. These average values do not justify concentration-independent liquid dosing.

Assess stool blood/fever, cause, hydration and electrolyte loss, abdominal swelling/constipation, response within 48 hours and hepatic/CNS risks. Review all interacting medicines and arrhythmia risks; symptomatic cardiac events or overdose require urgent ECG/electrolyte and clinical assessment. Routine serum loperamide concentrations are not useful for guiding toxicity management.

Measure the exact liquid concentration with its supplied device and count total daily milligrams from every product. Do not exceed the label/prescription, continue OTC use beyond 2 days, or use it for opioid withdrawal. Replace fluids; get care for blood, fever, distention or worsening symptoms. Fainting, rapid/irregular heartbeat or unresponsiveness needs emergency help. Use caution driving if drowsy/dizzy.

GSMS/Edenbridge prescription 2 mg capsule: light-brown opaque cap/body with a symbol over 605; 100-capsule bottle NDC 51407-999-01. Verify the written label rather than identify by color alone.

Selected prescription capsules 2 mg (ANDA215001 Prescription); OTC softgels 2 mg (ANDA213070 OTC); liquid 1 mg per 7.5 mL (ANDA091292 OTC). This scope excludes fixed loperamide/simethicone combination dosing, injectable products and assumptions that the older label-mentioned 1 mg per 5 mL liquid is currently stocked.

Selected capsules and liquid: 20–25°C. Selected softgels: 20–25°C, protect from light and excessive heat above 40°C; do not use torn/open blister units. Keep package directions, expiry and child-resistant/tamper-evident protection; shake the liquid before measuring.