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Larin Fe 1.5/30 and Nelfinavir

Determining the interaction of Larin Fe 1.5/30 and Nelfinavir and the possibility of their joint administration.

Check result:
Larin Fe 1.5/30 <> Nelfinavir
Relevance: 21.02.2023 Reviewer: Shkutko P.M., M.D., in

In the database of official manuals used in the service creation an interaction registered by statistical results of studies was found, which can either lead to negative consequences for the patient health or strengthen a mutual positive effect. A doctor should be consulted to address the issue of joint drug administration.

Consumer:

Nelfinavir may reduce the blood levels and effects of ethinyl estradiol. If you are using birth control pills or another hormone-type contraceptive such as a patch, shot, vaginal ring or implant, you should talk to your doctor before taking nelfinavir. You may need an alternative or additional method of birth control during and for at least two weeks after treatment with nelfinavir in order to avoid an unintended pregnancy. Let your doctor know if you experience bleeding outside of your menstrual cycle, since it may indicate reduced effectiveness of ethinyl estradiol. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Professional:

ADDITIONAL CONTRACEPTION RECOMMENDED: Nelfinavir may decrease the plasma concentrations of contraceptive hormones during chronic coadministration. The proposed mechanism is nelfinavir induction of the hepatic metabolism of sex hormones. In 12 study subjects, nelfinavir (750 mg every 8 hours for 7 days) decreased the mean peak plasma concentration (Cmax), area under the concentration-time curve (AUC) and trough plasma concentration (Cmin) of ethinyl estradiol (administered as ethinyl estradiol-norethindrone 0.035 mg-0.4 mg once a day for 15 days) by 28%, 47% and 62%, respectively, compared to administration of the oral contraceptive alone. The mean AUC and Cmin of norethindrone decreased by 18% and 46%, respectively.

MANAGEMENT: Women using hormonal contraceptives should be advised of the risk of breakthrough bleeding and unintended pregnancy during concomitant therapy with nelfinavir. Alternative or additional methods of birth control should be used during and for at least 4 weeks after nelfinavir therapy.
-If a combination oral contraceptive pill is used, a regimen containing at least 50 mcg of ethinyl estradiol per day or equivalent should be selected. Although breakthrough bleeding is not necessarily indicative of low ethinyl estradiol serum levels or increased risk of ovulation, some clinicians suggest that women who experience breakthrough bleeding during enzyme-inducing therapy may be prescribed an increased dose of ethinyl estradiol above 50 mcg daily by combining more than one formulation of contraceptive pill if necessary.
-For emergency contraception in patients who have used an hepatic enzyme inducer in the past 4 weeks, a non-hormonal emergency contraceptive (e.g., copper intrauterine device) is considered preferable. If this is not possible, some authorities recommend that the usual dose of levonorgestrel (1.5 mg) should be doubled to 3 mg and taken as a single dose as soon as possible (within 72 hours of unprotected sexual intercourse). However, there are no data on efficacy, compliance, or side effects of this regimen.
-No precautions or recommendations are available for women using hormone-releasing intrauterine systems, but a significant interaction with these systems is thought to be unlikely due to their local action. -Injectable progestin-only contraceptives are also thought to be unaffected by enzyme-inducing drugs.

References
  • Faculty of Sexual & Reproductive Healthcare "FSRH Clinical Guidance: Drug Interactions with Hormonal Contraception. Available from: URL: file:///C:/Users/df033684/Downloads/ceuguidancedruginteractionshormonal.pdf." ([2012, Jan 1]):
  • "Product Information. Viracept (nelfinavir)." Agouron Pharma Inc, La Jolla, CA.
  • Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  • "FFPRHC Guidance (April 2005). Drug interactions with hormonal contraception." J Fam Plann Reprod Health Care 31 (2005): 139-51
Larin Fe 1.5/30

Generic Name: ethinyl estradiol / norethindrone

Brand name: Blisovi 24 Fe, Blisovi Fe 15/30, Blisovi Fe 1/20, Estrostep Fe, Gildess 24 Fe, Gildess Fe 15/30, Gildess Fe 1/20, Junel Fe 15/30, Junel Fe 1/20, Junel Fe 24, Larin 24 Fe, Larin Fe 15/30, Larin Fe 1/20, Lo Loestrin Fe, Loestrin 24 Fe, Loestrin Fe 15/30, Loestrin Fe 1/20, Lomedia 24 Fe, Microgestin 24 Fe, Microgestin Fe 15/30, Microgestin Fe 1/20, Tarina Fe 1/20, Taytulla, Tilia Fe, Tri-Legest Fe, Blisovi 24 Fe, Femcon Fe, Kaitlib FE, Lo Minastrin Fe, Microgestin 24 Fe, Norinyl 1+35, Ortho-Novum 7/7/7, Tri-Norinyl, Zenchent, femhrt 05 mg/25 mcg, Fyavolv, Jevantique Lo, Jinteli, Femcon Fe, Generess FE, Loestrin 1/20, Ovcon 35, Brevicon

Synonyms: n.a.

Nelfinavir

Generic Name: nelfinavir

Brand name: Viracept

Synonyms: n.a.

In the course of checking the drug compatibility and interactions, data from the following reference sources was used: Drugs.com, Rxlist.com, Webmd.com, Medscape.com.

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