Drug interaction of methadone with oral contraceptive medication. Clinic, treatment and therapeutic drug monitoring

Introduction:

Drug therapy in patients with methadone and oral contraceptive can be challenging cause of relevant drug interactions which should be taken into account in clinical practice. Here we present a case of a 22 year old women. Patient additionally suffered from methadone addiction, affective disorder, attention deficit disorder, Hashimoto-Thyreoiditis and was treated with methadone, bupropion, doxepine and oral contraceptive steroids ethinyl estradiol.

Methods:

Clinical course documentation, measurement of drug levels.

Results:

Methadone is in high range before taking ethinyl estradiol (in serum 653 ng/ml, therapeutic range 50 – 400 ng/ml). Methadone serum-level decreased after two month during ethyl estradiol intake (154 ng/ml, 75 ng/ml). After stop oral contraceptives serum level of methadone increase due to 373 ng/ml. Due to the insufficient low methadone serum level, patient suffer of withdrawals like mydriasis, dreams of drugs, depressive mood. Due to the withdrawals of methadone a combination of doxepine and bupropion was chosen, both effected a sufficient plasma level.

Conclusion:

Methadone serum-level decreased during ethinyl estradiol intake and increased after stop taken pills. The treatment of methadone addiction and oral contraceptives indicates the necessity of individualized treatment, taking account of therapeutic drug monitoring before through and after contraceptives therapy.