TRI LO SPRINTEC
Clinical safety rating: caution
Comprehensive clinical and safety monograph for TRI LO SPRINTEC (TRI LO SPRINTEC).
Tri-Lo Sprintec is a combination oral contraceptive containing ethinyl estradiol and norgestimate. It inhibits ovulation by suppressing gonadotropin release (FSH and LH) from the pituitary, increases viscosity of cervical mucus, and alters endometrial receptivity.
| Metabolism | Ethinyl estradiol is metabolized primarily via CYP3A4; norgestimate is rapidly metabolized to norelgestromin and subsequently to norgestrel, with further metabolism involving CYP3A4 and other CYP enzymes. |
| Excretion | Renal (approximately 50-60% as metabolites, with about 20% as unchanged ethinyl estradiol glucuronide and 40% as norgestimate metabolites). Fecal (approximately 30-40% as metabolites). |
| Half-life | Ethinyl estradiol: terminal half-life approximately 17 hours. Norelgestromin (active metabolite of norgestimate): terminal half-life approximately 28 hours. Clinical context: Ethinyl estradiol half-life supports once-daily dosing with steady-state reached within 7-14 days; norelgestromin half-life allows for sustained progestogenic effect. |
| Protein binding | Ethinyl estradiol: approximately 97-98% bound to albumin, 2% free. Norelgestromin: approximately 99% bound to sex hormone-binding globulin (SHBG) and albumin. |
| Volume of Distribution | Ethinyl estradiol: Vd approximately 4-5 L/kg. Norelgestromin: Vd approximately 3-4 L/kg. Clinical meaning: indicates extensive distribution into tissues, not primarily confined to plasma volume. |
| Bioavailability | Oral: ethinyl estradiol bioavailability approximately 45% (first-pass effect); norgestimate prodrug converted to norelgestromin with systemic bioavailability of approximately 63%. |
| Onset of Action | Oral: contraceptive effect begins after 7 days of consistent daily dosing; full suppression of ovulation achieved within the first cycle. |
| Duration of Action | Oral: contraceptive effect lasts as long as daily dosing continues. Clinical note: if a dose is missed, backup contraception is recommended if missed dose exceeds 48 hours. |
| Molecular Weight | Ethinyl estradiol: 296.4 Da; norgestimate: 369.5 Da |
| Action Class | Oral Contraceptive; Estrogen/Progestin Combination |
One tablet (0.035 mg ethinyl estradiol + 0.180/0.215/0.250 mg norgestimate) orally once daily for 28-day cycle: active tablets on days 1-21, placebo on days 22-28.
| Dosage form | TABLET |
| Renal impairment | No specific dosing adjustment required for renal impairment. Use caution in severe renal impairment due to potential fluid retention. |
| Liver impairment | Contraindicated in severe hepatic disease or hepatocellular carcinoma. For mild to moderate hepatic impairment (Child-Pugh A or B), use alternative contraception; no established dosing guidelines. |
| Pediatric use | Not indicated for use before menarche. Post-menarche: same dosing as adults (one tablet daily). Safety and efficacy established in females of reproductive age. |
| Geriatric use | Not indicated for postmenopausal women; no geriatric dosing established. |
| 1st trimester | Contraindicated. Use during first trimester is associated with an increased risk of neural tube defects and cardiovascular malformations due to the progestin component (norgestimate). |
| 2nd trimester | Contraindicated. Use during second trimester is associated with potential hepatotoxicity and masculinization of female fetuses from androgenic progestins. |
| 3rd trimester | Contraindicated. Use during third trimester may cause withdrawal bleeding, premature delivery, and fetal bone suppression if used near term. |
Clinical note
Comprehensive clinical and safety monograph for TRI LO SPRINTEC (TRI LO SPRINTEC).
| Placental transfer | Both ethinyl estradiol and norgestimate (and its active metabolite norelgestromin) cross the placenta. Norelgestromin achieves fetal plasma concentrations approximately 10-20% of maternal levels. |
| Breastfeeding | Combined hormonal contraceptives including Tri-Lo Sprintec may reduce milk production and increase the risk of jaundice and breast engorgement in the infant. Use during breastfeeding is generally not recommended until weaning is complete. |
■ FDA Black Box Warning
Cigarette smoking increases the risk of serious cardiovascular events from combination oral contraceptive use. This risk increases with age and with heavy smoking (≥15 cigarettes per day) and is quite marked in women over 35 years of age. Women who use combination oral contraceptives should be strongly advised not to smoke.
| Common Effects | Nausea, Headache, Breast tenderness, Weight changes, Irregular menstrual bleeding, Mood changes, Acne |
| Serious Effects | Venous thromboembolism (deep vein thrombosis, pulmonary embolism), Arterial thromboembolism (myocardial infarction, stroke), Hepatic adenoma or hepatocellular carcinoma, Hypertension, Gallbladder disease, Cerebral hemorrhage, Optic neuritis or retinal thrombosis |
Thrombophlebitis or thromboembolic disorders, past or presentCerebrovascular or coronary artery diseaseKnown or suspected carcinoma of the breastCarcinoma of the endometrium or other estrogen-dependent neoplasiaUndiagnosed abnormal genital bleedingCholestatic jaundice of pregnancy or jaundice with prior oral contraceptive useHepatic adenoma or carcinomaKnown or suspected pregnancyHeavy smoking (≥15 cigarettes/day) in women over 35 years of age
| Precautions |
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| Lactation Rating | L4 (Possibly Hazardous) – potential for serious adverse effects. |
| Teratogenic Risk | FDA Category X. Use contraindicated in pregnancy due to risk of congenital anomalies, particularly cardiovascular and limb defects, from exposure during first trimester. Second and third trimester exposure associated with potential for fetal harm, including androgenization of female fetuses and liver adenoma. Discontinue promptly if pregnancy occurs. |
| Fetal Monitoring | Monitor blood pressure, liver function, and glucose tolerance. Assess for thromboembolic events. In pregnant women (unintended exposure), monitor fetal development via ultrasound for anomalies. |
| Fertility Effects | May impair fertility in some women by altering menstrual cycles and endometrial receptivity. Reversible upon discontinuation. No evidence of permanent effects. |
| Increased risk of thromboembolic disorders (e.g., venous thromboembolism, stroke, myocardial infarction), Cigarette smoking increases risk of serious cardiovascular events, Increased risk of hepatic neoplasia (benign and malignant), Elevated blood pressure, Gallbladder disease, Carbohydrate and lipid metabolic effects |
| Food/Dietary | No significant food interactions. Grapefruit may slightly alter estrogen metabolism but clinically not significant. Maintain consistent dietary habits if constipating. |
| Clinical Pearls | Tri-Lo Sprintec is a triphasic oral contraceptive with ethinyl estradiol and norgestimate. Monitor for thromboembolic events, especially in smokers over 35. Advise use of backup contraception if vomiting/diarrhea occurs. CYP3A4 inducers may reduce efficacy. |
| Patient Advice | Take one tablet daily at the same time; missed doses increase pregnancy risk. · Use backup contraception for 7 days after missing 2 or more pills. · Report symptoms of blood clots: leg pain/swelling, chest pain, sudden shortness of breath. · Avoid smoking while on this medication, especially if over 35. · May cause irregular bleeding initially; contact provider if persistent. |