Chlorhexidine

What is chlorhexidine?

Chlorhexidine is an antiseptic and disinfectant used to reduce bacteria and prevent infections. It is available in various forms, including mouthwash, creams, gels, sprays, lozenges, dressings, solutions and eye drops. You can buy it in pharmacies, shops, and supermarkets, as well as getting it on prescription. Brand names include Corsodyl, Covonia, Savlon, Dermol, and Germolene[1]. 

What is chlorhexidine used for?

Chlorhexidine is used to treat and prevent[1]: 

• Mouth ulcers 

• Gum disease (gingivitis) 

• Oral infections 

• Skin infections including a wash for acne 

• Pre-operative skin cleansing 

• Wound disinfection 

• Catheter site cleaning 

How does chlorhexidine work?

Chlorhexidine works by killing bacteria and preventing their growth. It reacts with the bacterial cell walls, disrupting their structure and causing them to die. This makes it effective for both treatment and prevention of infections[1]. 

Who can take chlorhexidine?

Most adults and children can use chlorhexidine, including pregnant and breastfeeding women, although seeking medical advice first is always recommended[1]. 

Chlorhexidine should not be used by people who are allergic to it, have difficulty swallowing, need to avoid alcohol, or have certain skin conditions unless advised by a doctor[1]. 

If you have a sore throat, do not use chlorhexidine and speak to your doctor if[1]: 

• your sore throat is severe 

• your sore throat has lasted for more than 2 days 

• you have problems swallowing 

• you have a high temperature 

• you have a headache 

• you're feeling or being sick (nausea or vomiting) 

Please tell your doctor or pharmacist about any conditions you may have or medication you take before you start treatment, and always follow the instructions in the Patient Information Leaflet[2].  

How do you take chlorhexidine?

It depends on the form of chlorhexidine you’re taking, but always follow the instructions from your doctor or in the medicine packet[1]: 

• Mouthwash - pour 10ml into the measuring cup, rinse the mouthwash around your mouth for about 1 minute, and spit out the mouthwash, never swallow 

• Lozenges – put one in your mouth and let it dissolve slowly, wait 30 minutes before eating or drinking 

• Throat spray – follow the instructions that come with the spray 

• Dental treatments – either use the gel to brush your teeth or apply it to the affected area by putting a small amount of it onto a fingertip or cotton bud first 

• Skin treatments – apply to clean, dry skin as directed by your doctor or the medicine packet 

• Nasal cream – apply to the inside of the nose as directed by your doctor

What is the typical dosage of chlorhexidine?

The dosage varies depending on the form of chlorhexidine, but always follow the instructions from your doctor or in the medicine packet[1]: 

• Mouthwash – the usual dose is 10ml twice daily without swallowing 

• Lozenges – adults can use up to 10 lozenges per day and children aged 12 years and over can have 5 a day 

• Throat spray – it contains a mixture of chlorhexidine and lidocaine, so follow instructions that come with the spray 

• Dental treatments – usually once or twice a day, but if you’re using dental gel, follow the instructions from your doctor, dentist, or pharmacist 

• Skin treatments – usually short-term and as needed for a few weeks 

• Nasal cream – as directed by your doctor 

Can you stop taking chlorhexidine?

You should not stop using chlorhexidine early unless advised by a healthcare professional. Stopping treatment too soon may allow the infection to return. If symptoms persist after one week, consult your doctor or pharmacist[1]. 

What do you do if you take too much chlorhexidine?

If you swallow a small amount of chlorhexidine mouthwash or gel, you may experience mild stomach upset. Skin irritation from overuse can be relieved by washing the area and stopping use. If large amounts are ingested or symptoms are severe, seek immediate medical attention or contact 111 for advice[1]. 

What do you do if you forget to take chlorhexidine?

If you forget a dose, use it as soon as you remember. If it is nearly time for your next dose, skip the missed one. Do not take two doses at once to make up for a missed dose[1]. 

What medicines can’t you take with chlorhexidine?

Dental, sore throat, and skin treatments are not known to cause problems if taken at the same time as other medicines. However, toothpaste can reduce effectiveness so wait five minutes after brushing and rinse mouth with water before using it. Speak to your doctor first before using it alongside other antiseptics or any herbal remedies[1]. 

Always inform your doctor or pharmacist about all medications and supplements you take before you start a new medicine, and follow the instructions in the Patient Information Leaflet[2]. 

What are the side effects of chlorhexidine?

There are no common side effects with chlorhexidine skin treatments. However, in rare cases, some people may get itchy, irritated or red skin, usually because they’ve applied too much lotion or cream where you have skin folds or creases.  

Common side effects of chlorhexidine sore throat and dental treatments include dry mouth, a burning or tingling sensation, staining of the teeth or tongue, altered taste, and peeling inside the mouth.  

Rare side effects of chlorhexidine dental treatments may include a sore or irritated mouth. Call 111 or speak to a doctor if you get a widespread skin rash. 

You should contact your GP if you experience any of these symptoms. In rare cases, the medicine may cause a serious allergic reaction (anaphylaxis). You should call 999 or visit A&E immediately if you believe this is happening[1]. 

Symptoms of anaphylaxis include[1]:  

• Difficulty breathing  

• Tightness in throat and chest  

• Swelling of the tongue or throat  

• Feeling faint or dizzy  

• Blue/grey skin or lips  

• Loss of consciousness 

If you experience any side effects, including those not listed, you are encouraged to report them via the Yellow Card Scheme or contact your doctor, pharmacist, or nurse. This information is intended as a summary for general awareness and does not replace professional medical advice. 

The information provided in the side effects section is not a comprehensive list of all possible side effects associated with this medication. For a complete list of side effects, please refer to the Patient Information Leaflet (PIL) provided with your medication or consult your healthcare professional[2]. 

Frequently asked questions about chlorhexidine

Can I swallow chlorhexidine mouthwash? 
No, it should be spat out after rinsing[1]. 

Can children use it? 
Yes but use age-appropriate formulations and check with a pharmacist or doctor[1]. 

Can I use chlorhexidine long-term? 
It is typically recommended for short-term use unless directed otherwise by a doctor[1]. 

What if I have sensitive skin? 
Test a small area first or consult a doctor before use. Use sparingly, especially with premature infants[1]. 

Does it kill viruses? 
Chlorhexidine is primarily antibacterial and is not effective against most viruses[1]. 

For the official NHS guide to chlorhexidine, visit their website.