Usage
Niclosamide is an anthelmintic medication primarily prescribed for the treatment of intestinal tapeworm infections. Specifically, it is effective against infections caused by Taenia saginata (beef tapeworm), Taenia solium (pork tapeworm), Diphyllobothrium latum (fish tapeworm), and Hymenolepis nana (dwarf tapeworm). It is not effective against pinworms or roundworms.
Alternate Names
Niclosamide is also known as Niclocide and Niclosan. Brand names include Yomesan and Niclocide.
How It Works
Pharmacodynamics: Niclosamide’s primary mechanism of action involves uncoupling oxidative phosphorylation within the tapeworm’s mitochondria. This process disrupts the parasite’s energy production, leading to its death. The dead worms are then passed in the stool. It primarily acts locally in the intestinal lumen, with minimal systemic absorption.
Pharmacokinetics: Niclosamide is minimally absorbed from the gastrointestinal tract. This limited absorption explains its localized action within the intestine and minimizes systemic side effects. Due to its poor absorption, detailed pharmacokinetic parameters such as half-life and volume of distribution are not well-defined. Elimination primarily occurs through fecal excretion of the unabsorbed drug.
Dosage
Standard Dosage
Adults:
For T. saginata, T. solium, D. latum: A single 2-gram dose is recommended. This dose can be repeated in 7 days if needed. In some cases, the 2-gram dose can be divided into two 1-gram doses taken one hour apart. For H. nana: 2 grams daily for 7 days. Treatment can be repeated in 7-14 days if required.
Children:
Dosing is weight-based:
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< 2 years: T. saginata, T. solium, D. latum: 500 mg single dose; H. nana: 500 mg on day 1, then 250 mg daily for 6 days.
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2-6 years: T. saginata, T. solium, D. latum: 1 gram single dose; H. nana: 1 gram on day 1, then 500 mg daily for 6 days.
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> 6 years: T. saginata, T. solium, D. latum: 2 grams single dose; H. nana: 2 grams on day 1, then 1 gram daily for 6 days.
For children between 11-34 kg: T. saginata, T. solium, D. latum: 1 gram as a single dose; H. nana: 1 gram on day 1, then 500 mg daily for 6 days.
For children weighing over 34 kg: T. saginata, T. solium, D. latum: 1.5 grams as a single dose; H. nana: 1.5 grams on day 1, then 1 gram daily for 6 days.
Special Cases:
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Elderly Patients: Due to minimal systemic absorption, no specific dosage adjustments are typically required.
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Patients with Renal Impairment: No dosage adjustments are needed due to the drug’s minimal systemic absorption.
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Patients with Hepatic Dysfunction: No dosage adjustments are necessary due to the drug’s minimal systemic absorption.
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Patients with Comorbid Conditions: No specific adjustments are routinely made. Individualized assessment is advisable.
Clinical Use Cases
Niclosamide is not indicated for use in clinical scenarios like intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations. Its sole indication is for the treatment of intestinal tapeworm infections.
Side Effects
Common Side Effects
Gastrointestinal disturbances, including nausea, vomiting, abdominal pain, diarrhea, loss of appetite, and unpleasant taste. Itching of the rectal area may also occur.
Rare but Serious Side Effects
Though rare, hypersensitivity reactions like skin rash and facial swelling are possible.
Contraindications
Known hypersensitivity to niclosamide is a contraindication.
Drug Interactions
Niclosamide has few known drug interactions due to its minimal systemic absorption. However, it can theoretically reduce the effectiveness of hormonal contraceptives. Caution is advised with concurrent use of medications metabolized by CYP450 enzymes, although significant interactions are unlikely. Concomitant use with alcohol may potentially increase gastrointestinal side effects.
Pregnancy and Breastfeeding
Niclosamide is classified as Pregnancy Category B. Limited human data exists. While animal studies have not shown fetal harm, its use during pregnancy should be carefully considered, weighing the benefits of treatment against potential risks. While it’s not known if niclosamide is excreted in breast milk, the minimal systemic absorption suggests minimal risk to the infant. The World Health Organization considers niclosamide compatible with breastfeeding.
Drug Profile Summary
- Mechanism of Action: Uncouples oxidative phosphorylation in tapeworms, leading to their death.
- Side Effects: Primarily gastrointestinal (nausea, vomiting, abdominal pain, diarrhea).
- Contraindications: Hypersensitivity to niclosamide.
- Drug Interactions: Potential interaction with hormonal contraceptives.
- Pregnancy & Breastfeeding: Category B; minimal risk anticipated; considered compatible with breastfeeding.
- Dosage: Adults: 2 grams single dose (can be divided) for most tapeworms; 2 grams daily for 7 days for H. nana. Pediatric doses are weight-based.
- Monitoring Parameters: Stool examination for tapeworm segments and ova.
Precautions
- General Precautions: Assess for any history of hypersensitivity to niclosamide.
- Specific Populations: Monitor pregnant women carefully if treatment is deemed necessary. No special precautions needed for breastfeeding mothers, children or elderly.
- Lifestyle Considerations: Concurrent alcohol use may exacerbate gastrointestinal side effects.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Niclosamide?
A: The standard adult dose is 2 grams as a single dose for T. saginata, T. solium, and D. latum and 2 grams daily for 7 days for H. nana. Children’s dosages are weight-based.
Q2: How does Niclosamide work?
A: It inhibits oxidative phosphorylation in the tapeworm mitochondria, leading to the parasite’s death.
Q3: What are the common side effects of Niclosamide?
A: Common side effects include nausea, vomiting, abdominal pain, and diarrhea.
Q4: Is Niclosamide safe during pregnancy?
A: It is a Pregnancy Category B drug. Use during pregnancy requires careful consideration of risks and benefits.
Q5: Can Niclosamide be used in breastfeeding mothers?
A: Yes, it is considered compatible with breastfeeding.
Q6: Are there any drug interactions with Niclosamide?
A: It can potentially reduce the effectiveness of hormonal contraceptives.
Q7: Does Niclosamide require any special dietary restrictions?
A: It’s generally recommended to take it after a light meal to minimize gastrointestinal upset.
Q8: How is Niclosamide eliminated from the body?
A: It is primarily eliminated in the feces as the unabsorbed drug.
Q9: Is Niclosamide effective against all types of worms?
A: No, it’s only effective against tapeworms. It is not effective against pinworms or roundworms.
Q10: What should a patient do if they vomit after taking Niclosamide?
A: In the event of vomiting shortly after administration, the dose may be repeated.
