Itraconazole in pregnancy and breastfeeding

Itraconazole]]>

Risk Factor: CM
Class: Anti-infectives/ Antifungals

Contents of this page:
Fetal Risk Summary
Breast Feeding Summary
References

Fetal Risk Summary

Itraconazole is a triazole antifungal agent that is structurally related to a number of other antifungal agents, including the imidazole-derivatives butoconazole, clotrimazole, and ketoconazole, and to the triazoles, fluconazole and terconazole (1).

A dose-related increase in toxicity and teratogenicity was found in both rats and mice (2). In pregnant rats treated with a dosage range 5 to 20 times the maximum recommended human dose (MRHD), maternal and embryo toxicity were observed, as were major skeletal malformations. In mice given 10 times the MRHD, maternal toxicity, embryo toxicity, and malformations consisting of encephaloceles or macroglossia occurred.

It is not known if itraconazole crosses the human placenta. The molecular weight (about 706) is low enough that passage to the fetus should be expected.

Cohort data presented at a 1996 meeting on single-dose fluconazole or itraconazole exposures during organogenesis did not demonstrate adverse outcomes in approximately 70 exposed pregnancies (3). However, the FDA has received 14 case reports of malformations following use of itraconazole, 4 of which involved limb defects (includes 1 case of agenesis of the fingers and toes) (3).

A 1998 noninterventional observational cohort study described the outcomes of pregnancies in women who had been prescribed one or more of 34 newly marketed drugs by general practitioners in England (4). Data were obtained by questionnaires sent to the prescribing physicians one month after the expected or possible date of delivery. In 831 (78%) of the pregnancies, a newly marketed drug was thought to have been taken during the 1st trimester with birth defects noted in 14 (2.5%) singleton births of the 557 newborns (10 sets of twins). In addition, two birth defects were observed in aborted fetuses. However, few of the aborted fetuses were examined. Itraconazole was taken during the 1st trimester in 41 pregnancies. The outcomes of these pregnancies included 1 ectopic pregnancy, 2 spontaneous abortions, 6 elective abortions, 2 cases lost to follow-up, and 30 normal newborns (1 premature) (4). One of the normal, full-term newborns, however, had a minor congenital anomaly consisting of a thin, prominent and protruding left ear. Although no major congenital malformations were observed, the study lacked the sensitivity to identify minor anomalies because of the absence of standardized examinations. Late appearing major defects may also have been missed due to the timing of the questionnaires.

A prospective cohort study published in 2000 evaluated the pregnancy outcomes of 198 women exposed to itraconazole in the 1st trimester (5). The pregnancy exposures had been reported to the manufacturer, before the outcomes were known, between April 1989 and June 1998. The median itraconazole dose was 200 mg (range 50800 mg) with a mean therapy duration of 8.5 12.4 days (range 190 days). A matched control group (N=198) was formed from pregnant women who had contacted the Motherisk Program, a teratogen information service in Toronto, Canada. The control group had not been exposed to any known teratogens (acceptable exposures were acetaminophen, penicillins, prenatal vitamins, dental radiography, or no exposures). There were no statistical differences between the groups in gravidity, parity, alcohol use, or cigarette smoking, but the maternal age in the study group was less than controls (30.1 vs. 31.0 years, p=0.02). Among pregnancy outcomes, there were no statistical differences between the groups in delivery method, rates of term, preterm, and postterm deliveries, 1- and 5-minute Apgar scores, sex ratios, and rates of neonatal complications. Significantly more pregnancy losses occurred in the exposed group than in controls (p
In summary, the available human data do not show that itraconazole poses a significant risk for major anomalies in humans. None of the above studies, however, adequately looked for minor malformations. Moreover, another azole antifungal agent, fluconazole, has demonstrated a possible dose-related relationship with major malformations (see Fluconazole). Therefore, the safest course is to avoid itraconazole, if possible, during organogenesis. If inadvertent exposure does occur during the 1st trimester, or if itraconazole must be used during early pregnancy, the woman can be reassured that the risk to her embryo or fetus, if it exists at all, is most likely low.

Breast Feeding Summary

Itraconazole is excreted into human breast milk. Two healthy lactating women each took two oral doses of 200 mg 12 hours apart (total dose 400 mg) (personal communication, EK Cazzaniga and A Chanlam, Janssen Pharmaceuticals, 1996). Neither infant was allowed to nurse during the study. At 4, 24, and 48 hours after the second dose, the average milk concentrations of itraconazole were 70, 28, and 16 ng/mL, respectively. At 72 hours, the milk level was 20 ng/mL in one woman and not detectable (
Although the above amount seems small, peak plasma concentrations in healthy male volunteers taking itraconazole 200 mg twice daily were not reached until about 15 days (2). The mean peak concentration of the parent compound in these volunteers was 2282 ng/mL, or about 15 times the average peak concentration measured in the two women above. Moreover, the mean plasma concentration of one of the metabolites (hydroxyitraconazole) exceeded that of the parent compound. Additionally, in animal studies, itraconazole accumulated in fatty tissues, omentum, liver, kidney, and skin tissues at levels 220 times the corresponding plasma concentration (2). Thus, continuous daily dosing, even with lower doses, should result in milk levels of the drug much higher than those found above and could result in widespread tissue accumulation in nursing infants. Because the potential effects of this exposure have not been studied, women taking itraconazole should probably not breast-feed.

References

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  1. American Hospital Formulary Service. Drug Information 1997. Bethesda, MD:American Society of Health-System Pharmacists, 1997:935.
  2. Product information. Sporanox. Janssen Pharmaceutica, 2001.
  3. Rosa F. Azole fungicide pregnancy risks. Presented at the Ninth International Conference of the Organization of Teratology Information Services, May 24, 1996, Salt Lake City, Utah.
  4. Wilton LV, Pearce GL, Martin RM, Mackay FJ, Mann RD. The outcomes of pregnancy in women exposed to newly marketed drugs in general practice in England. Br J Obstet Gynaecol 1998;105:8829.
  5. Bar-Oz B, Moretti ME, Bishai R, Mareels G, Van Tittelboom T, Verspeelt J, Koren G. Pregnancy outcome after in utero exposure to itraconazole: a prospective cohort study. Am J Obstet Gynecol 2000;183:61720.

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