Mistra (Dienogest, Ethinylestradiol)

Mistra, a combined oral contraceptive, is used in hormonal regulation of the reproductive system.

• Contraception: provides reliable prevention of pregnancy when taken as prescribed.
• Regulation of menstrual cycles: helps reduce irregular bleeding and dysmenorrhea.
• Management of acne associated with androgen excess: can improve acne symptoms in women using hormonal control.

• Mistra combines ethinylestradiol, a synthetic estrogen, with dienogest, a progestogen. The estrogen component suppresses follicle‑stimulating hormone (FSH) release, while the progestogen inhibits luteinizing hormone (LH) surge, preventing ovulation. Additionally, the progestogen thickens cervical mucus and induces endometrial changes that reduce the likelihood of implantation.

Mistra may cause a range of adverse reactions, most of which are mild and transient.

Common Side Effects

• Nausea: mild to moderate stomach upset.
• Headache: occasional tension‑type headaches.
• Breast tenderness: temporary swelling or discomfort.
• Spotting between periods: light bleeding or spotting.

Serious or Rare Side Effects

• Deep vein thrombosis: blood clot formation in deep veins.
• Pulmonary embolism: clot migration to lung vessels.
• Severe allergic reaction: rash, swelling, or anaphylaxis.
• Liver dysfunction: abnormal liver enzyme elevations.
• Stroke or myocardial infarction: rare cerebrovascular or cardiac events.

Before prescribing Mistra, clinicians should evaluate individual risk factors and contraindications.

• Pregnancy: avoid use if pregnant or suspected pregnancy.
• Smoking: contraindicated in women over 35 who smoke.
• Cardiovascular risk: assess history of thromboembolic disorders.
• Liver disease: use with caution in hepatic impairment.
• Drug interactions: review concomitant medications for CYP3A4 modulators.
• Store at ambient temperature: keep below 25°C, in the original pack, and protect from moisture.

Mistra can interact with several medicines, affecting efficacy or safety.

Major Interactions (Avoid)

• CYP3A4 inducers (e.g., rifampin, carbamazepine): may reduce contraceptive effectiveness.
• Potent CYP3A4 inhibitors (e.g., ketoconazole, itraconazole): may increase hormone levels and risk of side effects.
• Anticoagulants (e.g., warfarin): may increase thrombotic risk.
• Antiepileptic drugs (e.g., phenytoin, phenobarbital): may lower contraceptive efficacy.

Moderate Interactions (Monitor Closely)

• Certain antibiotics (e.g., tetracycline, metronidazole): may slightly reduce absorption.
• Herbal supplements (e.g., St. John's wort): may decrease hormonal levels.
• Selective serotonin reuptake inhibitors (e.g., fluoxetine): may augment mood‑related side effects.