Fusidic acid (Fucidin): cream, ointment and eye drops explained

Fusidic acid is an antibiotic that kills bacteria by stopping them growing and spreading. The NHS lists skin infections, impetigo among them, and eye infections such as conjunctivitis as the main uses. It comes as cream, ointment and eye drops, and tablets, liquid and injection exist too, though this guide is about the topical forms.

The brand name is Fucidin. Combination products with a steroid, sold as Fucibet and Fucidin H, are used when inflammation is part of the picture. Because the antibiotic works at the site, the NHS notes there is no real risk of the thrush that oral antibiotics can cause.

Wash your hands before and after applying, unless you are treating the hands. Put a thin layer on the infected skin and rub it in gently, and take care to avoid the eyes if you are using it on the face. Cream and ointment are used 3 to 4 times a day, or twice a day if the product also contains a steroid, usually for 1 to 2 weeks.

Keep using it until the course is finished, even if the skin looks better. The NHS says you should start to improve within a few days, and to speak to your doctor if there is no improvement after 7 days.

• Missed application: use it as soon as you remember, then carry on with the usual schedule.

• Swallowing a small amount is unlikely to cause harm; ask a pharmacist or doctor if you are concerned about a larger amount.

Fusidic acid eye drops come as a gel in a tube. The usual pattern is one drop in the affected eye in the morning and evening, and treatment continues for at least 48 hours after the symptoms have gone. Do not let the tip of the tube touch your eye.

Expect temporary blurred vision after a dose, so wait until it clears before driving, cycling or using machinery. Take out contact lenses during treatment and wait 24 hours after the last dose before putting them back in.

The NHS says most adults and children can use fusidic acid cream, ointment and eye drops. The main reason not to is a previous allergic reaction to fusidic acid or to another medicine, which you should tell the prescriber about.

The NHS says it is not suitable for some people, so mention your history, including any reaction to a product that contains a steroid if you have been given a combination cream.

Side effects are unusual with the cream or ointment. Skin irritation where it is applied affects fewer than 1 in 100 people. Eye drops are different: more than 1 in 10 users notice burning, stinging, itching, soreness, dryness or blurred vision in the treated eye, and a cool compress can ease it.

• Call NHS 111 if an eye infection gets worse, if burning or stinging persists, or if hives or raised itchy patches appear.

• Call 999 for sudden swelling of the lips, mouth, throat or tongue, severe breathing difficulty, throat tightness, blue, grey or pale skin, sudden confusion or collapse.

The NHS says fusidic acid is safe in pregnancy, because very little reaches the baby and the small amount that does will not harm them. It is generally safe while breastfeeding: avoid putting it on the breasts, wash your hands before handling the baby, and if you are treating impetigo on the nipple, wash it off before feeding. Cream is easier to remove than ointment. There is no evidence of reduced fertility.

It does not affect contraception, including the combined pill and emergency contraception. Alcohol and food make no difference. Suspected side effects can be reported through the Yellow Card scheme.