Iodoquinol (Monograph)

Brand name: Yodoxin
Drug class: Amebicides
- Antiprotozoal Agents

Medically reviewed by Drugs.com on Apr 10, 2024. Written by ASHP.

Introduction

Amebicide, antiprotozoal.

Uses for Iodoquinol

Amebiasis

Treatment of amebiasis caused by Entamoeba histolytica.

Used alone for treatment of asymptomatic intestinal amebiasis. Drugs of choice for asymptomatic cyst passers (intraluminal infections) are iodoquinol, paromomycin, or oral diloxanide furoate (not commercially available in the US). Paromomycin may be preferred in children or pregnant women.

Should not be used alone for treatment of symptomatic intestinal amebiasis or extraintestinal amebiasis (including amebic liver abscess) caused by E. histolytica. Regimen of choice for symptomatic intestinal amebiasis or extraintestinal disease (including liver abscess) is treatment with a tissue amebicide (oral metronidazole or oral tinidazole) followed by treatment with a luminal amebicide (oral iodoquinol or oral paromomycin). Paromomycin may be preferred for such follow-up treatment in children or pregnant women.

Some strains of Entamoeba are nonpathogenic (e.g., E. dispar, E. hartmanni) and asymptomatic intraluminal infections with these organisms generally do not require treatment.

Balantidiasis

Treatment of balantidiasis^{† [off-label]} caused by Balantidium coli. Tetracycline is considered the drug of choice; alternatives are iodoquinol or metronidazole.

Blastocystis hominis Infections

Has been used in the treatment of infections caused by Blastocystis hominis^{† [off-label]}.

Clinical importance of B. hominis as a cause of GI pathology is controversial; unclear when treatment is indicated. Some clinicians suggest treatment be reserved for certain individuals (e.g., immunocompromised patients) when symptoms persist and no other pathogen or process is found to explain their GI symptoms.

Treatment alternatives are metronidazole, co-trimoxazole, iodoquinol, or nitazoxanide. Metronidazole resistance may be common in some areas.

Dientamoeba fragilis Infections

Treatment of infections caused by Dientamoeba fragilis^{† [off-label]}.

Drugs of choice are iodoquinol, paromomycin, tetracycline, or metronidazole.

Iodoquinol Dosage and Administration

Administration

Oral Administration

Administer orally after a meal. Tablets may be crushed and mixed with applesauce or chocolate syrup.

Dosage

Pediatric Patients

Amebiasis Caused by Entamoeba histolytica

Asymptomatic Amebiasis

Oral

30–40 mg/kg daily (maximum: 2 g daily) administered in 3 divided doses for 20 days.

Manufacturer recommends 10–13.3 mg/kg 3 times daily (up to 1.95 g daily) for 20 days.

Symptomatic Intestinal Amebiasis or Extraintestinal Amebiasis (Including Amebic Liver Abscess)

Oral

30–40 mg/kg daily (maximum: 2 g daily) administered in 3 divided doses for 20 days.

Manufacturer recommends 10–13.3 mg/kg 3 times daily (up to 1.95 g daily) for 20 days.

Used as follow-up after a tissue amebicide (oral metronidazole or oral tinidazole). (See Amebiasis under Uses.)

Balantidiasis† [off-label]

Oral

30–40 mg/kg daily (maximum: 2 g daily) given in 3 divided doses for 20 days.

Dientamoeba fragilis Infections† [off-label]

Oral

30–40 mg/kg daily (maximum: 2 g daily) given in 3 divided doses for 20 days.

Adults

Amebiasis Caused by Entamoeba histolytica

Asymptomatic Amebiasis

Oral

650 mg 3 times daily for 20 days.

Symptomatic Intestinal Amebiasis or Extraintestinal Amebiasis (Including Amebic Liver Abscess)

Oral

650 mg 3 times daily for 20 days.

Balantidiasis†

Oral

650 mg 3 times daily for 20 days.

Blastocystis hominis Infections†

Oral

650 mg 3 times daily for 20 days.

Dientamoeba fragilis Infections†

Oral

650 mg 3 times daily for 20 days.

Prescribing Limits

Pediatric Patients

Amebiasis Caused by Entamoeba histolytica

Oral

Maximum 1.95 or 2 g daily.

Balantidiasis†

Oral

Maximum 2 g daily.

Dientamoeba fragilis Infections†

Oral

Maximum 2 g daily.

Special Populations

No special population dosage recommendations at this time.

Cautions for Iodoquinol

Contraindications

• Known hypersensitivity to iodine and 8-hydroxyquinolines.

• Hepatic disease.

Warnings/Precautions

Warnings

Optic Neuritis and Peripheral Neurotoxicity

Avoid long-term use. Prolonged, high dosage of halogenated 8-hydroxyquinolines has resulted in optic neuritis, optic atrophy, and peripheral neuropathy .

Sensitivity Reactions

Hypersensitivity

Discontinue if hypersensitivity reactions occur.

General Precautions

Thyroid Disease

Use with caution in individuals with thyroid disease. (See Laboratory Tests under Interactions.)

Nonspecific Diarrhea

Do not use for the treatment of nonspecific diarrhea.

Specific Populations

Pregnancy

Category C.

Lactation

Not known whether iodoquinol is distributed into milk, safe use during lactation not established.

Pediatric Use

Do not exceed maximum daily dosage.

Hepatic Impairment

Contraindicated in patients with hepatic disease.

Common Adverse Effects

Iodism manifested by generalized furunculosis (iodine toxicoderma) and skin reactions (papular and pustular acneiform eruptions, bullae, vegetating or tuberous iododerma), urticaria and pruritus, GI effects (anorexia, nausea, vomiting, diarrhea, abdominal cramps, pruritus ani), fever, chills, headache, vertigo, thyroid enlargement, optic neuritis, optic atrophy, peripheral neuropathy.

Drug Interactions

Laboratory Tests

Contains 64% organically-bound iodine. May interfere with certain thyroid function tests by increasing protein-bound serum iodine concentrations. This effect may persist for as long as 6 months after cessation of iodoquinol therapy.

Iodoquinol Pharmacokinetics

Absorption

Bioavailability

Poorly absorbed from the GI tract; majority of an oral dose is excreted in feces

Some systemic absorption may occur since increased blood concentrations of iodine have been reported.

Distribution

Extent

Animal studies indicate the drug is distributed into tissues. Free iodine appears in urine.

Elimination

Elimination Route

Unabsorbed drug is eliminated in feces. Glucuronide and sulfate conjugates of iodoquinol are eliminated in urine.

Stability

Storage

Oral

Tablets

15–30°C in well-closed containers.

Actions and Spectrum

• A luminal or contact 8-hydroxyquinoline amebicide, acts primarily in the intestinal lumen. Precise mechanism of action unknown.

• Amebicidal against Entamoeba histolytica. Active against both the trophozoite and encysted forms. Elimination of the cyst form probably results from destruction of the trophozoites.

Advice to Patients

• Importance of taking after a meal.

• Importance of completing full course of treatment, even if feeling better after a few days.

• Importance of notifying clinician of persistent or worsening symptoms of infection.

• Importance of informing clinicians if hypersensitivity reactions or rash occurs.

• Importance of women informing clinicians if they are or plan to become pregnant or plan to breast-feed.

• Importance of informing patients of other important precautionary information. (See Cautions.)

Preparations

Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.

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