This information page contains advice on the safe handling, administration, and disposal of Fluorouracil (5-FU) eye drops 1%. It is important that you follow the instructions carefully before using your eye drops.
You have been prescribed 5-FU eye drops to treat an ocular oncology condition. A major benefit of topical chemotherapy is that it kills potential tumour cells over the entire surface of the eye, eradicating not only visible tumour cells but also cells that are too small to be visible.
5-FU prevents cells from multiplying. It can be harmful if misused. It is therefore important that you handle your drops with care, using them only as prescribed.
One drop should be put into the affected eye four times daily, spaced evenly apart. The time of day that the drops are used is not important, but the even spacing of drop administration throughout the day is. One example of the correct way to place the drops would be to use one drop at 7:00am, 12:00pm, 5:00pm and 10:00pm.
Each cycle of treatment lasts four days, although occasionally this will differ. The ocular oncologist or nurse will discuss the length of treatment with you.
Each cycle of therapy is usually followed by a rest period of 24 days, when the drops are not used. There will be four cycles of treatment in total.
The drops should be stored in the fridge once opened. This is because the drops do not contain preservatives. The drops cannot be used beyond seven days after opening.
At the end of each cycle of treatment, the bottle of 5-FU, with its remaining contents, should be closed tightly and then placed into the purple-lidded cytotoxic waste bin which you have been provided with. Empty and part used bottles should be placed into this bin. Make sure you do not close the seal of the bin until you have placed the bottles from every 5-FU cycle into it.
The full bins should be disposed of via the waste department of your local council. Sometimes local GP practices, pharmacies or hospital pharmacies can help with disposal. Alternatively, you can return the full bins to the Moorfields pharmacy or the eye clinic. Do not throw any remaining liquid down the toilet or sink.
When using the 5-FU, it is advisable to wear disposable gloves and apply a barrier cream (e.g. Vaseline, moisturiser cream) on the surrounding skin of your eye and eyelids. Any used tissues and gloves (turn gloves inside out as you remove them) should be double-bagged in plastic bags then thrown away with your normal household waste.
As long as only trace amounts (i.e. a drop or two) of the drops come into contact with the gloves/tissues, there is no need to dispose of these into the purple-lidded cytotoxic waste bin.
Should you need to use other eye drops at the same time of day, please leave at least five minutes between the different drops to prevent one drop from diluting the other.
If you have been asked to instil FML (fluorometholone) drops, this is a steroid drop that helps with inflammation on the surface of the eye. Shake the drop bottle for 30 seconds before applying the drop.
The chemotherapy drops may sting at first. They usually cause the eye to become inflamed, watery, and sensitive to light, with redness and swelling of the eyelids.
If the reaction becomes severe, you should seek advice from the ocular oncology provider or nurse (details can be found at the end of this leaflet). Sometimes simultaneous treatment with steroid drops, such as fluorometholone, which acts only on the ocular surface (without penetrating the eye), may be helpful.
Additionally, you may use preservative-free artificial tears or ointment for any discomfort and/or a warm or cold compress. Hold the compress on for 15 minutes at a time – 15 minutes on and then 15 minutes off. Seek advice from the ocular oncology provider or nurse if needed.
Chemotherapy drops only affect tumour cells close to the surface of the conjunctiva (i.e., in the epithelium); they do not penetrate deep into the conjunctiva and are therefore ineffective for invasive tumour.
In about a third of patients, the ocular disease is not eliminated by the topical chemotherapy, such that the tumour persists or recurs after months or years. Life-long monitoring is therefore necessary in all patients. Biopsy may be needed in the future to determine whether there is any active microscopic disease.
5-FU causes minimal or no impairment of the conjunctiva’s ability to regenerate, meaning that persistent corneal ulceration and haziness are unlikely to occur.
The chemotherapy drops can cause blockage of the tear ducts, (specifically, the puncta) which can result in a permanently watery eye. Some doctors therefore ask the patient to press on the tear duct for five minutes after instilling drops, or they insert plugs to try to prevent this complication. Others do not wish to prevent the chemotherapy agents from entering the tear ducts in case any tumour cells have seeded into these passages. Your doctor should have discussed this with you. For any questions, see “further information” section.
5-FU eye drops do not result in detectable levels of the drug in your blood.
It is advisable for you to attend our clinic after your first cycle of treatment so that we can manage any side effects. If you experience significant discomfort, we would like to see you without delay (see “further information” section below for who to contact).
You will be reviewed in the eye clinic at the end of the treatment. Further review appointments are decided on a case-by-case basis at the discretion of the ophthalmologist.
5-FU drops should be avoided in pregnancy and in the presence of any conditions predisposing to corneal ulceration (e.g. herpetic keratitis).
After any eye operation, 5-FU drops should be avoided before the surgical wound has healed and this takes about 2 weeks. Safety for use in pregnancy has not yet been established therefore handling or use of the drops is not recommended during pregnancy. Care should be taken if there is any risk of pregnancy or if breastfeeding.
There may be other treatments available, and the doctor will have discussed these with you. If you feel that you need any further information, please ask your provider or specialist ocular oncology nurse.
The tumour may continue to grow. This might make treatment more difficult and could make your eye painful. There may be an increased risk of the tumour spreading out of the eye and to other parts of the body.
The drops will be supplied to you one bottle at a time, typically once every four weeks, from the Moorfields pharmacy department. This is necessary because the drops have a short expiry. The pharmacy will be in touch to discuss the delivery dates. If you need assistance, the oncology pharmacist can be contacted on 020 7253 ext. 4285 (Monday to Friday, 9am – 5:30pm) (e-mail: dominic.sergian@nhs.net). If the oncology pharmacist is not available, you can contact the medicines information department on 020 7566 2362 (Monday to Friday, 9am – 5:30pm).
The eye drops have been prescribed for you only and you must never let anyone else use them.
You can store your drops safely by placing the bottle in a glass jar, container with a lid, or plastic bag. Remember to store your drops in the fridge once opened.
The drops can be toxic if used incorrectly, so please ensure that they are stored in a safe place out of the reach of children.
If redness or irritation lasts for longer than a few hours, contact your GP or clinic.
Both men and women should use birth control methods during and for three months following treatment with chemotherapy eye drops to prevent possible foetal damage.
If you have any questions, please contact us.
For queries during working hours, please contact the oncology nurse or oncology/adnexal secretaries via the number given to you by the clinic nurse.
For emergencies or after hours please contact the Moorfields switchboard and ask to speak to the oncology fellow on call. Alternatively, if you’re worried, you may wish to attend your local eye unit/A&E. Pharmacy is unable to advise on whether the drops should be discontinued in response to side effects. For this, a doctor’s input is required.
Author: Dominic Sergian
Review date: January 2028