OPCICON ONE-STEP
Clinical safety rating: caution
Comprehensive clinical and safety monograph for OPCICON ONE-STEP (OPCICON ONE-STEP).
Opcicon One-Step (levonorgestrel) is a progestin that inhibits ovulation and fertilization by suppressing luteinizing hormone (LH) surge, altering tubal transport, and thickening cervical mucus to impede sperm penetration.
| Metabolism | Hepatic via CYP3A4; also metabolized by CYP2C19, CYP2C9, and CYP2D6. Undergoes conjugation and reduction. |
| Excretion | Opcicon One-Step (levonorgestrel) is primarily excreted as glucuronide conjugates. Renal excretion accounts for approximately 45% of the dose, with fecal excretion constituting about 32%. |
| Half-life | The terminal elimination half-life of levonorgestrel is approximately 25 hours (range 10-45 hours). This long half-life provides sustained contraceptive effect over several days after a single dose. |
| Protein binding | Levonorgestrel is highly protein-bound: approximately 97.5% bound to sex hormone-binding globulin (SHBG) and albumin. |
| Volume of Distribution | Volume of distribution is about 1.8 L/kg (range 1.3-2.4 L/kg), indicating extensive distribution into tissues. |
| Bioavailability | Oral bioavailability of levonorgestrel is nearly 100% (approximately 95-100%) as it undergoes minimal first-pass metabolism. |
| Onset of Action | Oral administration: ovulation inhibition occurs within 24 hours if taken just prior to ovulation; peak plasma levels reached 1-2 hours post-dose. |
| Duration of Action | Approximately 72-120 hours (3-5 days) for contraceptive effect; sufficient to cover the fertile window following unprotected intercourse. Clinical efficacy persists for at least 5 days. |
No data available.
| Dosage form | TABLET |
| Renal impairment | No data available. |
| Liver impairment | No data available. |
| Pediatric use | No data available. |
| Geriatric use | No data available. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for OPCICON ONE-STEP (OPCICON ONE-STEP).
| Breastfeeding | Naproxen and omeprazole both excreted into breast milk. Naproxen M/P ratio ~0.01. Low risk at typical doses; however, consider infant risk of NSAID-related adverse effects. Alternatives preferred. |
| Teratogenic Risk | No human data; animal studies insufficient. First trimester: theoretical risk based on mechanism, but no specific malformations identified. Second/third trimester: risk of premature ductus arteriosus closure and oligohydramnios from NSAID component (naproxen). Avoid in pregnancy, especially after 30 weeks. |
■ FDA Black Box Warning
None
| Serious Effects |
["Known hypersensitivity to levonorgestrel","Current pregnancy (not for termination)","Severe hepatic impairment"]
| Precautions | ["Not effective if already pregnant","May reduce efficacy of regular hormonal contraceptives","Menstrual cycle disturbances","Ectopic pregnancy risk if used after conception","Hepatic impairment (use with caution)"] |
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| Fetal Monitoring |
| Monitor fetal ultrasound for ductus arteriosus and amniotic fluid index if used in third trimester. Maternal monitoring for GI bleeding, renal function, and blood pressure. |
| Fertility Effects | NSAIDs may impair female fertility via inhibition of prostaglandin synthesis affecting ovulation; reversible upon discontinuation. No known effect on male fertility. |