Short-Course Itraconazole and Contraceptive Efficacy
If itraconazole is given for only one week, Sprintec (ethinyl estradiol/norgestimate) contraception remains effective and no additional contraceptive measures are required. The evidence shows that non-rifamycin antifungals, including azoles like itraconazole, do not significantly interact with hormonal contraceptives to reduce their effectiveness.
Evidence-Based Reasoning
No Clinically Significant Drug Interaction
The most relevant and high-quality evidence comes from a systematic review examining drug interactions between antibiotics and hormonal contraception 1. While this study focused primarily on antibiotics, the pharmacokinetic principles apply to azole antifungals as well. The review found no significant decreases in progestin pharmacokinetic parameters during co-administration with antimicrobial agents, and ethinyl estradiol levels remained stable with most agents 1.
More specifically, a pharmacokinetic study of voriconazole (another azole antifungal) co-administered with an oral contraceptive containing norethindrone and ethinyl estradiol actually showed increased systemic exposure of both the contraceptive components rather than decreased levels 2. Ethinyl estradiol AUC increased 61% and norethindrone AUC increased 53% during azole co-administration 2. This demonstrates that azole antifungals do not reduce contraceptive hormone levels—if anything, they may increase them through CYP450 enzyme inhibition.
Duration Considerations
A one-week course of itraconazole is too short to meaningfully impact contraceptive efficacy. The CDC guidelines for missed or late contraceptive pills specify that backup contraception is only needed when hormonal pills have been interrupted or missed for ≥48 hours 3. Since itraconazole does not interrupt pill-taking and does not reduce hormone levels, this threshold is never reached.
Clinical Practice Implications
- Continue Sprintec as prescribed during the week of itraconazole therapy
- No backup contraception needed (no condoms, no abstinence required)
- No need to extend the pill pack or skip the hormone-free interval
- No emergency contraception indicated unless pills are actually missed for other reasons
Important Caveats
The Rifamycin Exception
This recommendation applies specifically to itraconazole and other azole antifungals. Rifamycin antibiotics (rifampin, rifabutin) are the major exception and DO significantly reduce contraceptive efficacy through CYP450 enzyme induction 4. These require backup contraception during use and for 28 days after discontinuation.
When Backup Contraception IS Needed
According to CDC guidelines, backup contraception for 7 consecutive days is required only when 3, 5:
- Two or more consecutive hormonal pills are missed (≥48 hours since a pill should have been taken)
- Severe vomiting or diarrhea occurs for ≥48 hours after taking pills
- Rifamycin antibiotics are used
- Certain anticonvulsants or other strong enzyme inducers are started
Monitoring Considerations
While contraceptive efficacy is maintained, the increased hormone exposure from azole-contraceptive interaction 2 means patients should be monitored for:
- Estrogen-related side effects (nausea, breast tenderness, headache)
- Breakthrough bleeding (though this is not an indicator of reduced efficacy)
- Azole-related adverse effects, which may be slightly increased
Bottom Line
One week of itraconazole does not compromise Sprintec contraception. The pharmacokinetic evidence shows azoles inhibit rather than induce metabolism of contraceptive hormones, and the short duration is insufficient to cause any clinically meaningful change in contraceptive protection. Continue the contraceptive as usual without additional measures.