Adverse reactions 

Therapy should be discontinued if the following occur: ̵ Jaundice or deterioration in liver function ̵ Significant increase in blood pressure ̵ New onset of migraine-type headache or more frequent occurrence of unusually severe headaches ̵ Pregnancy ̵ Sudden perceptual disorders (e.g. disturbances of vision or hearing) ̵ First signs of thrombophlebitis or thromboembolic symptoms

• Norethisterone should be withdrawn immediately if venous thromboembolism (VTE) develops contact your doctor immediately if you become aware of a potential thromboembolic symptom, including : - Painful swelling in the leg - Sudden pain in the chest - Dyspnoea

• If you develop an acute impairment of vision, proptosis, diplopia or migraine headache you should be referred for an ophthalmology evaluation to exclude papilloedema or retinal vascular lesions

• Liver tumours have been reported in users of hormonal substances such as the one contained in norethisterone. If severe upper abdominal complaints, liver enlargement or signs of intra-abdominal haemorrhage occur, discontinue treatment and see your GP 

Pregnancy

• If menstrual bleeding should fail to follow a course of norethisterone, the possibility of pregnancy must be excluded before a further course is given.

Surgery

• Where prolonged immobilisation is likely to follow elective surgery, particularly abdominal or orthopaedic surgery to the lower limbs, consideration should be given to stopping norethisterone treatment 4-6 weeks pre-operatively. Treatment should not be restarted until you are fully remobilised 

Warnings

• If the symptoms persist, or you experiences other severe symptoms please contact your GP, call NHS 111 or visit A&E. 
• if menstrual bleeding should fail to follow a course of norethisterone, you should not take any more until certain you are not pregnant.
• If of childbearing potential use a barrier contraception for the duration of treatment.
• Contact the health care professional if you start taking any new medical products that may be contraindicated with norethisterone.