Synthetic oestrogen

Ethinylestradiol

Brand names: various combination products

Adult dose

Dose: Component of combined hormonal contraception or HRT — see specific preparation

Route: Oral / Transdermal / Vaginal

Frequency: Per preparation

Clinical pearls

Almost always prescribed as a combined preparation (CHC/HRT)
FSRH UKMEC eligibility criteria essential before prescribing
MHRA: VTE risk varies by progestogen partner — levonorgestrel/norethisterone-containing CHCs have lowest VTE risk

Contraindications

Past or active VTE/arterial events
Migraine with aura
Smokers >35 years
Breast cancer
Severe hepatic disease
Pregnancy

Side effects

Breakthrough bleeding
Breast tenderness
Headache
VTE
Stroke
Hypertension
Cholestasis

Interactions

Enzyme inducers (carbamazepine, rifampicin, ritonavir, St John's wort — reduced contraceptive efficacy)
Lamotrigine (lowers lamotrigine levels)
FSRH guidance on drug interactions with hormonal contraception

Monitoring

BP
Migraine pattern
Breast awareness
VTE risk factors

Reference: BNF; FSRH UKMEC; MHRA Drug Safety Update; https://bnf.nice.org.uk/drugs/ethinylestradiol/. Verify against your local formulary and the latest BNF before prescribing.

Curated clinical cross-links plus same-class fallbacks.

Pathways