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.¹¹⁰

Uses for Iodoquinol

Amebiasis

Treatment of amebiasis caused by Entamoeba histolytica.^{100 102 105 106 107 110}

Used alone for treatment of asymptomatic intestinal amebiasis.^{100 102 105 106 107} Drugs of choice for asymptomatic cyst passers (intraluminal infections) are iodoquinol, paromomycin, or oral diloxanide furoate (not commercially available in the US).^{100 102 105 106 107} Paromomycin may be preferred in children or pregnant women.^{105 106}

Should not be used alone for treatment of symptomatic intestinal amebiasis or extraintestinal amebiasis (including amebic liver abscess) caused by E. histolytica.^{100 102 105 106 107} 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).^{100 102 105 106 107} Paromomycin may be preferred for such follow-up treatment in children or pregnant women.^{105 106}

Some strains of Entamoeba are nonpathogenic (e.g., E. dispar, E. hartmanni) and asymptomatic intraluminal infections with these organisms generally do not require treatment.^{100 105 106 107}

Balantidiasis

Treatment of balantidiasis^{† [off-label]} caused by Balantidium coli.^{100 102 106} Tetracycline is considered the drug of choice; alternatives are iodoquinol or metronidazole.^{100 102 106}

Blastocystis hominis Infections

Has been used in the treatment of infections caused by Blastocystis hominis^{† [off-label]}.^{100 102 106 108 109}

Clinical importance of B. hominis as a cause of GI pathology is controversial;^{100 102 106 108 109} unclear when treatment is indicated.^{100 106 108} 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.^{100 106}

Treatment alternatives are metronidazole, co-trimoxazole, iodoquinol, or nitazoxanide.^{100 102} Metronidazole resistance may be common in some areas.¹⁰²

Dientamoeba fragilis Infections

Treatment of infections caused by Dientamoeba fragilis^{† [off-label]}.^{102 106}

Drugs of choice are iodoquinol, paromomycin, tetracycline, or metronidazole.^{102 106}

Related/similar drugs

doxycycline, metronidazole, Flagyl, Vibramycin, tinidazole, nitazoxanide, paromomycin

Iodoquinol Dosage and Administration

Administration

Oral Administration

Administer orally after a meal.^{102 110} Tablets may be crushed and mixed with applesauce or chocolate syrup.^a

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.^{102 107}

Manufacturer recommends 10–13.3 mg/kg 3 times daily (up to 1.95 g daily) for 20 days.¹¹⁰

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.^{102 107}

Manufacturer recommends 10–13.3 mg/kg 3 times daily (up to 1.95 g daily) for 20 days.¹¹⁰

Used as follow-up after a tissue amebicide (oral metronidazole or oral tinidazole).^{100 102 105 106 107} (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.¹⁰²

Dientamoeba fragilis Infections† [off-label]

Oral

30–40 mg/kg daily (maximum: 2 g daily) given in 3 divided doses for 20 days.¹⁰²

Adults

Amebiasis Caused by Entamoeba histolytica

Asymptomatic Amebiasis

Oral

650 mg 3 times daily for 20 days.^{102 105 107 110}

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

Oral

650 mg 3 times daily for 20 days.^{102 105 107 110}

Balantidiasis†

Oral

650 mg 3 times daily for 20 days.¹⁰²

Blastocystis hominis Infections†

Oral

650 mg 3 times daily for 20 days.^{102 109}

Dientamoeba fragilis Infections†

Oral

650 mg 3 times daily for 20 days.¹⁰²

Prescribing Limits

Pediatric Patients

Amebiasis Caused by Entamoeba histolytica

Oral

Maximum 1.95¹¹⁰ or 2 g daily.¹⁰²

Balantidiasis†

Oral

Maximum 2 g daily.¹⁰²

Dientamoeba fragilis Infections†

Oral

Maximum 2 g daily.¹⁰²

Special Populations

No special population dosage recommendations at this time.^a

Cautions for Iodoquinol

Contraindications

• Known hypersensitivity to iodine and 8-hydroxyquinolines.¹¹⁰

• Hepatic disease.¹¹⁰

Warnings/Precautions

Warnings

Optic Neuritis and Peripheral Neurotoxicity

Avoid long-term use.¹¹⁰ Prolonged, high dosage of halogenated 8-hydroxyquinolines has resulted in optic neuritis, optic atrophy, and peripheral neuropathy .¹¹⁰

Sensitivity Reactions

Hypersensitivity

Discontinue if hypersensitivity reactions occur.¹¹⁰

General Precautions

Thyroid Disease

Use with caution in individuals with thyroid disease.¹¹⁰ (See Laboratory Tests under Interactions.)

Nonspecific Diarrhea

Do not use for the treatment of nonspecific diarrhea.¹¹⁰

Specific Populations

Pregnancy

Category C.¹¹¹

Lactation

Not known whether iodoquinol is distributed into milk,¹¹¹ safe use during lactation not established.¹¹⁰

Pediatric Use

Do not exceed maximum daily dosage.¹¹⁰

Hepatic Impairment

Contraindicated in patients with hepatic disease.¹¹⁰

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.^{110 a}

Drug Interactions

Laboratory Tests

Contains 64% organically-bound iodine.¹¹⁰ May interfere with certain thyroid function tests by increasing protein-bound serum iodine concentrations.¹¹⁰ This effect may persist for as long as 6 months after cessation of iodoquinol therapy.¹¹⁰

Iodoquinol Pharmacokinetics

Absorption

Bioavailability

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

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

Distribution

Extent

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

Elimination

Elimination Route

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

Stability

Storage

Oral

Tablets

15–30°C¹¹⁰ in well-closed containers.^a

Actions and Spectrum

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

• Amebicidal against Entamoeba histolytica.¹¹⁰ Active against both the trophozoite and encysted forms.¹¹⁰ Elimination of the cyst form probably results from destruction of the trophozoites.^a

Advice to Patients

• Importance of taking after a meal.¹¹⁰

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

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

• Importance of informing clinicians if hypersensitivity reactions or rash occurs.^{110 a}

• Importance of women informing clinicians if they are or plan to become pregnant or plan to breast-feed.¹¹⁰

• 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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