CU-7
Clinical safety rating: caution
Comprehensive clinical and safety monograph for CU-7 (CU-7).
The Cu-7 intrauterine device (IUD) releases copper ions, which inhibit sperm motility and viability, and alter the endometrial environment to prevent implantation.
| Metabolism | Copper ions are released locally in the uterine cavity and are not metabolized; systemic absorption is minimal. |
| Excretion | Primarily fecal (80-90%) as unabsorbed copper; negligible renal excretion (<1%). |
| Half-life | Not applicable; intrauterine device with no systemic elimination half-life. Copper release is continuous with a rate of approximately 38 µg/day, declining over time. |
| Protein binding | Copper ions bind to albumin (60%) and transcuprein (40%). |
| Volume of Distribution | Not applicable; negligible systemic absorption; copper released locally in uterus with minimal distribution. |
| Bioavailability | Not applicable; no systemic absorption; local intrauterine release only. |
| Onset of Action | Immediate contraceptive effect upon insertion; maximum effect within 24 hours. |
| Duration of Action | Effective for up to 10 years after insertion; can be removed at any time with immediate return to fertility. |
50 mg orally once daily
| Dosage form | INTRAUTERINE DEVICE |
| Renal impairment | No adjustment necessary |
| Liver impairment | No adjustment necessary |
| Pediatric use | Not approved for pediatric use |
| Geriatric use | No specific dose adjustment required, but monitor renal function |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for CU-7 (CU-7).
| Breastfeeding | CU-7 is compatible with breastfeeding. Copper is a normal dietary component and minimal systemic absorption occurs from the intrauterine device. No M/P ratio is applicable due to negligible systemic levels. |
| Teratogenic Risk | CU-7 (intrauterine copper contraceptive) is not indicated for use during pregnancy. If pregnancy occurs with CU-7 in situ, there is an increased risk of spontaneous abortion, septic abortion, and preterm delivery. No teratogenic effects have been demonstrated from copper exposure in utero. |
■ FDA Black Box Warning
CU-7 has been voluntarily withdrawn from the market by the manufacturer. No current FDA-approved black box warning exists; however, use of copper IUDs is associated with risk of pelvic inflammatory disease (PID) and perforation.
| Serious Effects |
["Pregnancy or suspected pregnancy","Known or suspected copper allergy","Wilson's disease","Abnormal uterine cavity (e.g., fibroids distorting cavity)","Acute or chronic pelvic infection including PID","Postpartum endometritis or infected abortion within past 3 months","Undiagnosed abnormal genital bleeding","Malignancy of the genital tract","Immunocompromised state"]
| Precautions | ["Risk of pelvic inflammatory disease (PID), especially in women with multiple sexual partners","Uterine perforation during insertion","Expulsion of the device","Irregular bleeding or spotting","Potential for ectopic pregnancy if pregnancy occurs","Anaphylaxis or allergic reaction to copper"] |
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| Fetal Monitoring |
| Monitor for signs of pregnancy, pelvic infection, uterine perforation, and expulsion. If pregnancy occurs, assess for ectopic pregnancy and remove the device if possible. |
| Fertility Effects | CU-7 does not impair future fertility. Fertility returns to baseline upon removal of the device. |