NICLOCIDE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for NICLOCIDE (NICLOCIDE).
Inhibits oxidative phosphorylation in cestodes, leading to paralysis and death of the parasite.
| Metabolism | Not extensively metabolized; excreted primarily unchanged in feces. |
| Excretion | Niclosamide is predominantly excreted in feces as unchanged drug and metabolites after oral administration. Renal excretion of metabolites accounts for less than 2% of an administered dose. Approximately 70% of the dose is recovered in feces within 2-3 days. |
| Half-life | The terminal elimination half-life of niclosamide is approximately 2-6 hours in patients with normal renal function; however, clinical efficacy against cestodes is prolonged due to its local action in the gastrointestinal tract. |
| Protein binding | Niclosamide is highly protein bound (approximately 97-99%), primarily to albumin. |
| Volume of Distribution | Volume of distribution (Vd) is not well characterized in humans due to minimal systemic absorption after oral dosing; estimated Vd is around 0.1-0.2 L/kg, reflecting low tissue distribution since it acts locally. |
| Bioavailability | Oral bioavailability is extremely low (<1%) due to extensive first-pass metabolism and minimal absorption; virtually all of the drug remains in the gastrointestinal lumen to exert its antihelmintic effect. |
| Onset of Action | Following oral administration, niclosamide exerts its cestocidal effect within minutes to hours as it acts locally on the tapeworm scolex and proximal segments, leading to paralysis and dislodgement. Systemic effects are not relevant. |
| Duration of Action | The duration of action is limited to the gastrointestinal passage of the drug; however, complete clearance of the tapeworm may require 1-2 days post-dose, with purgation often recommended to expel the dead parasite. Residual activity is negligible after 24 hours. |
| Molecular Weight | 327.14 |
2 g orally as a single dose, chewed thoroughly, for taeniasis; may repeat in 1 week for hymenolepiasis.
| Dosage form | TABLET, CHEWABLE |
| Renal impairment | No dose adjustment required for renal impairment; drug is minimally systemically absorbed. |
| Liver impairment | No dose adjustment required for hepatic impairment; drug acts locally in gastrointestinal tract. |
| Pediatric use | 50 mg/kg orally as a single dose (maximum 2 g), chewed thoroughly. |
| Geriatric use | No specific dose adjustment; use standard adult dosing with caution for swallowing and hydration. |
| 1st trimester | Limited data in pregnant women; animal studies are insufficient. Use only if clearly needed and potential benefit justifies risk to fetus. |
| 2nd trimester | Limited data; no known teratogenicity reported in humans. Use with caution. |
| 3rd trimester | Limited data; consider risk-benefit. May cause GI upset in mother; no known fetal harm. |
Clinical note
Comprehensive clinical and safety monograph for NICLOCIDE (NICLOCIDE).
| Placental transfer | Unknown; due to low systemic absorption (<10%), significant placental transfer is unlikely. |
| Breastfeeding | Niclosamide is minimally absorbed systemically (<10% oral dose); excreted in breast milk in unknown amounts. Considered compatible with breastfeeding due to low systemic exposure, but monitor infant for diarrhea or rash. |
■ FDA Black Box Warning
None.
| Serious Effects |
Hypersensitivity to niclosamide or any component of the formulation
| Precautions | May cause abdominal discomfort; use with caution in patients with hepatic impairment or ulcerative lesions of the bowel. |
| Food/Dietary | Take after a light breakfast or meal to reduce gastrointestinal side effects. Avoid alcohol for 24 hours post-dose due to risk of disulfiram-like reaction. No other significant food interactions. |
| Clinical Pearls | Administer after a light breakfast; crush tablets and mix with water for children or patients with difficulty swallowing. Avoid alcohol to prevent disulfiram-like reactions. Monitor for neurocysticercosis exacerbation if used for Taenia solium; pre-treat with corticosteroids to reduce inflammation. |
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| Lactation Rating |
| L2 (Probably Compatible) |
| Teratogenic Risk | Animal studies have not shown teratogenic effects, but no adequate human studies in pregnant women. Risk cannot be ruled out; use only if clearly needed. |
| Fetal Monitoring | Monitor for GI disturbances, dizziness, and allergic reactions. No specific fetal monitoring required. |
| Fertility Effects | No studies on fertility effects in humans; animal studies show no impairment. |
| Patient Advice | Take this medication only as prescribed, usually as a single dose after a light meal. · Crush the tablet and mix with a small amount of water or fruit juice if you have trouble swallowing. · Do not drink alcohol for at least 24 hours after taking niclosamide to avoid severe nausea and vomiting. · You may experience mild gastrointestinal upset; this is usually temporary. · Follow-up stool examinations are necessary to confirm the infection is cleared. |