desogestrel: clinical use

Prescribing considerations

• Exclude pregnancy and assess unexplained bleeding before initiation.
• Review breast-cancer history, thromboembolic disease, liver disease, diabetes, hypertension, mood disorders and interacting medicines.
• Counsel that bleeding may be unpredictable and persistent or unusually heavy bleeding requires assessment.
• Consider ectopic pregnancy when amenorrhoea or abdominal pain occurs.
• Assess adherence, gastrointestinal disturbance and interactions if contraceptive failure is suspected.

Contraindications and cautions

• Active venous thromboembolic disorder
• Current or previous severe hepatic disease while liver function remains abnormal
• Known or suspected sex-steroid-sensitive malignancy
• Undiagnosed vaginal bleeding
• Hypersensitivity to desogestrel or an excipient
• Rare hereditary galactose intolerance, total lactase deficiency or glucose-galactose malabsorption for the selected lactose-containing product

Monitoring

• No universal laboratory-monitoring schedule is specified; follow-up should reflect individual circumstances.
• Review persistent irregular bleeding, amenorrhoea with pregnancy risk, new depression, significant blood-pressure elevation, liver symptoms or deterioration of relevant disease.
• Observe diabetes control where clinically appropriate.
• During breastfeeding, consider infant growth and development if concerns arise.

Clinical pharmacology

Desogestrel is rapidly absorbed and converted to etonogestrel, which suppresses ovulation and increases cervical-mucus viscosity. Etonogestrel is highly protein-bound and metabolised through hydroxylation, dehydrogenation and conjugation pathways.

Formulation and product differences

• The selected Zelleta/Desogestrel product is a round, white to off-white, uncoated tablet supplied in calendar blister packs.
• The selected product contains lactose. Excipients and tablet appearance may differ between brands; check the specific product information.

Tablet

Route: Oral

Strengths: 75 micrograms