A sulfonamide antibiotic for eye infections
Sulfacetamide
A sulfonamide antibiotic used in eye drops and ointment for eye infections, and in some skin preparations.
What is Sulfacetamide?
Sulfacetamide is a sulfonamide antibiotic used mainly as eye drops or ointment to treat bacterial eye infections such as conjunctivitis, and in some skin preparations. It works by stopping bacteria from growing. The most common effect is local stinging or irritation when it is put in the eye, which usually settles quickly. The most important caution is that it should be avoided by anyone with a known allergy to sulfonamide medicines, because, although rare, serious skin reactions can occur with this group of drugs.
Education and reference only. This is a plain-language guide to Sulfacetamide — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Sulfacetamide is a long-established antibiotic that belongs to the sulfonamide group. It is used most often as eye drops or eye ointment to treat bacterial infections of the eye, such as conjunctivitis, and it also appears in some preparations used on the skin. Applied directly where it is needed, it tackles the bacteria causing the infection. It is a topical medicine rather than one taken by mouth for these uses, and is prescribed or recommended under medical or pharmacist guidance.
How it works
Bacteria need to make a substance called folate in order to grow and multiply. Sulfacetamide, like other sulfonamides, blocks one of the steps bacteria use to make folate, so the bacteria cannot grow and the infection is brought under control. Because it is applied directly to the eye or skin, it works mainly where it is put, which helps tackle a local infection. As an antibiotic, it works against bacteria and not against infections caused by viruses.
Company & origin
Originated / developed by: Various manufacturers.
A long-established sulfonamide antibiotic used mainly in eye drops and ointment for eye infections, and in some skin preparations.
Practical use
How to take Sulfacetamide
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Use the eye drops or ointment as directed, putting them into the affected eye as instructed.
- Do not let the dropper or tube tip touch your eye, eyelid or skin, to avoid spreading infection.
- Finish the course you are given, even if the eye looks better, unless told otherwise.
- Avoid wearing contact lenses while you have an eye infection unless your prescriber says it is fine.
- Stop and seek advice if you develop a spreading rash, blistering or swelling, which could be an allergy.
Weighing it up
Advantages & disadvantages of Sulfacetamide
Advantages
- An effective, long-established antibiotic for bacterial eye infections.
- Applied directly where it is needed as eye drops, ointment or skin preparations.
- Generally well tolerated, with stinging usually brief.
Disadvantages
- Commonly causes brief stinging or irritation when put in the eye.
- Must be avoided by people allergic to sulfonamide medicines.
- Rarely, sulfonamides can cause serious skin reactions, so any spreading rash needs review.
Practical use
Good to know
The most important safety point is allergy: because sulfacetamide is a sulfonamide, anyone who has had an allergic reaction to a sulfonamide medicine should avoid it, and although serious skin reactions with sulfonamides are rare, any spreading rash, blistering or swelling should be taken seriously and reviewed urgently. When used in the eye, it commonly causes brief stinging or irritation as it goes in, which usually settles quickly. To avoid spreading infection, do not let the dropper or tube tip touch your eye or skin, and follow advice on removing contact lenses while you have an eye infection. As with any antibiotic for an infection, finish the course you are given even if the eye looks better, and go back to your prescriber if it is not improving.
Who should not take it / use with caution
- People who are allergic to sulfacetamide or other sulfonamide medicines should not use it.
- It is used with care in pregnancy and breastfeeding, on medical advice.
- It is used only as directed, and a doctor should review eye infections that are severe or not improving.
Monitoring
- Reviewing whether the eye or skin infection is improving as expected.
- Watching for signs of an allergic reaction, including any spreading rash.
- Seeking review if symptoms are severe, worsening or not settling.
Side effects
- Local stinging, burning or irritation when put in the eye, usually brief.
- Temporary blurred vision just after using eye ointment.
- Redness or itching of the eye or skin in some people.
- Rarely but seriously, an allergic reaction, including serious skin reactions, which need urgent attention.
Key interactions
- Tell your prescriber about other eye drops or ointments so they can be spaced out correctly.
- Avoid using preparations you are allergic to, particularly other sulfonamide medicines.
- Always mention all your medicines, including those used on the skin or eyes.
Available as: Eye drops and eye ointment, and some preparations used on the skin.
Answers
Sulfacetamide: frequently asked questions
What is sulfacetamide used for?
It is a sulfonamide antibiotic used mainly as eye drops or ointment to treat bacterial eye infections such as conjunctivitis, and in some skin preparations.
Why does it sting when I put it in?
Brief stinging or irritation as the drops or ointment go in is the most common effect and usually settles quickly.
Can I use it if I am allergic to sulfa medicines?
No. Because sulfacetamide is a sulfonamide, you should avoid it if you have had an allergic reaction to a sulfonamide medicine.
Can I wear my contact lenses?
It is usually best not to wear contact lenses while you have an eye infection; ask your prescriber when it is safe to start again.
Should I finish the course?
Yes, finish the course you are given even if the eye looks better, and go back to your prescriber if it is not improving.
Authoritative sources
- BNF
- NICE CKS
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