Yodoxin

Generic Name: Iodoquinol
Class: Amebicides
VA Class: AP109

Introduction

Amebicide, antiprotozoal.110

Uses for Yodoxin

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

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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 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.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.102 106

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

Yodoxin 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
Oral

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

Dientamoeba fragilis Infections
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 Yodoxin

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

Interactions for Yodoxin

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

Yodoxin Pharmacokinetics

Absorption

Bioavailability

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

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.

Iodoquinol

Routes

Dosage Forms

Strengths

Brand Names

Manufacturer

Oral

Tablets

210 mg

Yodoxin

Glenwood

650 mg

Yodoxin

Glenwood

AHFS DI Essentials. © Copyright, 2004-2014, Selected Revisions September 1, 2009. American Society of Health-System Pharmacists, Inc., 7272 Wisconsin Avenue, Bethesda, Maryland 20814.

† Use is not currently included in the labeling approved by the US Food and Drug Administration.

References

100. American Academy of Pediatrics. 2006 Red Book: Report of the Committee on Infectious Diseases. 27th ed. Elk Grove Village, IL: American Academy of Pediatrics; 2006.

102. Anon. Drugs for parasitic infections. From the Medical Letter website. 2008 Aug.

105. Ravdin JI. Amebiasis. Clin Infect Dis. 1995; 20:1453-66. [IDIS 349015] [PubMed 7548493]

106. Aucott JN. Amebiasis and “nonpathogenic” intestinal protozoa. Infect Dis Clin North Am. 1993; 7:67-85.

107. Reed SL. Amebiasis: an update. Clin Infect Dis. 1992; 14:385-93. [IDIS 292053] [PubMed 1554822]

108. Miller RA. Blastocystis hominis: an organism in search of a disease. Rev Infect Dis. 1988; 10:930-8. [IDIS 309903] [PubMed 3055191]

109. Grossman I, Weiss LM, Simon D et al. Blastocystis hominis in hospital employees. Am J Gastroenterol. 1992; 87:729-32. [PubMed 1590309]

110. Glenwood. Yodoxin (iodoquinol) tablets prescribing information. From manufacturer’s website. Accessed 2009 May 11.

111. Briggs GG, Freeman RK, Yaffe SJ. Drugs in pregnancy and lactation. 8th ed. Baltimore, MD: Williams & Wilkins; 2008:843-4.

a. AHFS drug information 2009. McEvoy GK, ed. Iodoquinol. Bethesda, MD: American Society of Health-System Pharmacists; 2009:856-7.

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