Letrozole

Pregnancy & gynaecology-specific. Every dose row is source-referenced; verify against institutional protocols.

LetrozoleAromatase inhibitor

Regimens checked: 2026-10-17. Each indication has its own preparation, limits and safety checks.

Letrozole: indication-specific regimens
Indication	Dose	Route	Frequency	Duration / preparation	Maximum	Monitoring / cautions
Anovulatory PCOS infertility after assessment of pregnancy, tubal/semen factors and counselling about off-label use Gloucestershire Hospitals NHS Foundation Trustchecked	2.5 mg daily on cycle days 2–6	Oral	Once daily for 5 consecutive days per prescribed cycle	Initial monitored cycle, with review of ovulation/response before changing dose or repeating a course · One 2.5 mg tablet daily; day 1 is the first day of fresh menstrual bleeding. Exclude pregnancy before another cycle if no period PCOS 2023 guidance supports letrozole first line for anovulatory infertility without other infertility factors. Cycle-day schedules vary by clinic; follow one complete prescribed schedule.	2.5 mg/day in this named NHS starting regimen; dose escalation requires a new fertility prescription, not automatic self-escalation	Monitor Ovulation assessment, cycle/pregnancy outcome and ultrasound monitoring where indicated; discuss multiple-pregnancy risk Contraindications / cautions Possible/existing pregnancy, breastfeeding; hepatic impairment needs specialist assessment

Pregnancy safety

Exclude existing pregnancy before ovulation induction; do not give during pregnancy

Lactation

Not for use during breastfeeding