Medically reviewed by, Russell Braun RPH
Mupirocin ointment is an antibiotic that is used topically to prevent and treat bacterial infections. While it has a broad range of uses, all of them are for infections on the skin.
Mupirocin is a powerful antibiotic because it works differently than other antibiotics. While typical antibiotics disrupt bacteria from build cell walls, mupirocin acts inside the cell.
Kill bacteria not just slow them down
Many people are surprised to learn that some antibiotics are bacteriostatic. That simply means that they keep bacteria from reproducing, but do not kill them. This can be very bad because once that bacteria has seen that antibiotic it can build defenses to it allowing it to become resistant.
Mupiricon on the other hand is bactericidal. That means mupirocin actually kills the bacteria. Hence, it is often a go to antibiotic for infections of the skin.
How does mupirocin work?
Mupirocin works on an enzyme that is found inside the bacterial cell called RNA synthetase. It blocks the effects of this enzyme and as a result prevents the bacteria from making proteins it needs to survive.
What bacteria does mupirocin kill?
Mupirocin is effective at treating skin infections because it kills the two main species of bacteria that are present on our skin. Normally these bacteria act as “normal flora”, which are helpful to the host they live on. However, when something damages the skin, tears and cracks in the skin can allow these bacteria into places where its growth becomes harmful.
Back in 1987 mupirocin was found to be very effective against mostly gram positive and a few gram negative bacteria. Gram staining simply refers to a way to group bacteria based on the way their cell wall reacts to a staining process done in a lab. This is important clinically to help select the types of antibiotics that will kill a particular bacteria.
Mupirocin has been shown to kill the following types of bacteria:
Positive Gram Stain
- Staphylococcus aureus
- Methicillin-Resistant Staphylococcus Aureus (MRSA)
- Streptococcus pyogenes
- Beta-hemolytic streptococcus
Negative Gram Stain
- Hemophilus influenzae
- Neisseria gonorrhoeae
What about bacterial resistance?
Antibiotic resistance is a major problem today. Thousands of people die each year from infections that antibiotics can’t kill. Bacteria develop resistance when exposed to an antibiotic. The antibiotics that are taken by mouth or given intravenously in a hospital get into he blood stream and are exposed to bacteria all over the body. An advantage to topical only mupirocin is that it does not get exposed to all different types of bacteria and therefore is less likely to develop resistance.
Most antibiotics work in a different way than mupirocin also causing bacteria to become resistant to them. However, because mupirocin is bacteriacidal, it is much less likely to have resistance built up to it.
The probability of cross resistance, or resistance to the same bacteria as other classes of antibiotics is low for mupirocin. That is why it is a good choice for tough infections. However, bacteria are very good at developing resistance. Hard to treat bacteria such as Staphylococcus aureus or methicillin-resistant staphylococcus aureus (MRSA) have been found to be resistant in increasing numbers in recent years.
What do you treat with Mupirocin?
Because mupirocin is a strong antibiotic it has multiple uses. Mupiriocin is FDA approved for the topical treatment of impetigo due to susceptible strains of Staphylococcus aureus and Streptococcus pyogenes bacteria. The table below summarizes the infections mupirocin is typically used to treat.
|Impetigo||Secondary skin infections|
|Treatment of MRSA||Prevention of MRSA|
|Prevention of MRSA|
|Minor skin infections|
Impetigo also known as a “staph” bacterial infection of the skin. It is common especially in children and is highly contagious. It appears as red sores that appear and then burst open with puss that oozes out. Finally, the dried puss looks like a honeycomb crust.
Treatment with mupirocin is quickly effective, also patients are no longer contagious after 24 hours of starting it.
2. Secondary Skin Infections
Secondary skin infections are bacterial infections of pre-existing injuries to the skin. These typically first present as wounds, cuts, burns or cysts that were not initially a problem but become infected as they are healing.
3. Treatment of MRSA
Most people have Staphylococcus aureus on their skin that does not cause a problem. However, MRSA can be very problematic and lead to very difficult to treat infections. Due to the resistance of MRSA to many antibiotics, mupirocin is a valuable tool to stop the spread of the infection.
4. Prevention of MRSA
MRSA can be spread from one person to another quite easily especially when it is intranasal. Because one sneeze can release thousands of tiny droplets that can contain MRSA. As a result the bacteria can easily be spread to others who unkowingly inhale the microdroplets in the air.
Therefore, mupirocin is an important tool to stop this spread in patients known to carry nasal MRSA.
5. Prevention of MRSA before surgery
When patients have surgery they may have tubes that go up their nose or if not, their immune system is stressed. These can both allow MRSA found inside the nasal passages to spread and cause infection. Therefore, using mupirocin in patients who have been tested for MRSA prior to surgery is becoming more common.
6. Furuncle (Boil)
Hair follicles can become infected for a variety of reasons. When they do and the infection is especially deep it can lead to an abscess that is referred to as furuncle or boil. Click here to find out more on mupirocin treatment for boils.
7. Minor skin infections
There are many other skin infections that are due to Streptococcus and staphylococcus bacteria. Examples include:
Mupirocin is a great option in these cases because of the bacteria it is effective in killing.
Keep in mind that mupirocin does not kill any type of fungus. Therefore, it can’t be used for things like ringworm or yeast infections.
Is muprirocin absorbed through the skin?
Mupirocin is available as a topical ointment or cream. There are no oral tablet or capsule forms. Therefore, the drug must be applied to the skin. While mupirocin does penetrate through the outer layers of the skin, it is not absorbed well enough to get into the bloodstream.
When used in adults nasally, mupirocin absorption has been shown to be minimal according to Physicians Digital Reference. They suggest only about 3% of the dose would be absorbed.
Nasal use in children under 12 has not been studied. Because children often absorb drugs differently than adults, you should consult with your doctor before using nasal mupirocin on a child.
Can Mupirocin be used on an open wound?
Mupirocin is not supposed to be used on large open wounds. The reason is this would allow for more of the mupirocin to potentially be absorbed into the bloodstream, which could be harmful.
Inactive ingredients in the ointment such as polyethylene glycol could be absorbed. High enough amounts of this could cause kidney damage.
In addition to open wounds use caution when using mupirocin in the eyes, nose or inside of the mouth. All of these areas make absorption of the ointment much easier than when it is applied to the skin. Rinsing with water should be done if you do get the cream on these areas.
How much Mupirocin should you use and how often?
Mupirocin is available as a cream or an ointment. Both contain 2% mupirocin and the drug is intended to be used topically (or on the skin) or intranasally.
Impetigo and skin infections
The prescribing information for mupirocin recommends applying a small amount of the ointment on the affected areas with a cotton swab or gauze pad. Rub the medication in gently until it appears clear on the skin. Finally, apply the drug three times per day.
Your doctor will give instructions on how long it should be used for but up to 10 days can be expected. Typically patients see a response in 3 to 5 days.
Studies have shown that mupirocin can treat nasal MRSA and prevent the risk of spreading it to others. However, the dose is different than for skin infections.
For intranasal use, it should be applied in both nostrils twice a day. The recommended amount is 1 gram total, or 0.5 grams in each nostril for each dose. There are nasal mupirocin packets that contain just 1 gram of the drug, but most patients will have a 22 gram tube. Finally, ask your doctor or pharmacist how to measure out the 1 gram dose if you only have the tube.
Other key points for appropriate usage
- Wash your hands before preparing to use mupirocin.
- Wash with water or antiseptic agents as prescribed by your doctor first.
- Clean and dry the affected areas before applying.
- Do not apply any other lotions, creams or sunscreens unless directed by your doctor or pharmacist.
- Covering the area with a bandage is optional.
- Continue to apply the medication even if the infection appears to go away. This is very important to prevent resistance or a recurrence of the infection!
- Wash your hands to get any residual mupirocin off your hands.
- Keep the lid closed tightly and store at room temperature. Do not keep in the refrigerator or in excessive heat.
How much does Mupirocin cost?
Mupirocin is a prescription only medication. Consequently, you can’t buy it over the counter at the pharmacy. That means your insurance is more likely to cover it than to make you buy it with cash out of your pocket.
The good news is Bactroban the brand version of mupirocin was first FDA approved way back in 1987. That means it’s patent has long since expired and the generic, mupirocin can now be made by generic manufacturers.
Cost according to GoodRx
- Mupirocin 2%, 22 gram tube costs $9.99
- Bactoban 2%, 30 gram tube costs $177.73 !
Key cost saving tips
- Make sure you ask for and get the generic, there is no need to pay the higher cost of brand name Bactroban.
- Mupirocin comes in a 22 gram tube that is more than enough to treat most skin infections. Only get one tube at the pharmacy unless you have a very large area to treat.
For more medication cost savings ideas check out 5 Simple ways to get Prescription Savings.
What are the side effects of mupirocin?
Antibiotics that are taken by mouth or intravenously kill good bacteria and bad bacteria as they flow throughout the body. This can cause unwanted side effects in addition to the desired one. Consequently this is another key benefit of mupirocin being a topical mediation because it causes fewer side effects.
Most side effects from mupirocin are mild, typically not needing medical attention. Similarly, most side effects may go away after a few days of use, remember this is often used for up to 10 days.
The most reported side effects of mupirocin at the site of application are listed in the table below.
|Side effect||Percentage of |
|Rash||Less than 1%|
|Nausea||Less than 1%|
|Erythema (Redness)||Less than 1%|
|Dry skin||Less than 1%|
|Tenderness||Less than 1%|
|Swelling||Less than 1%|
|Contact dermatitis||Less than 1%|
|Increased oozing of infection||Less than 1%|
Your pharmacist is a great resource to ensure proper use of the medication. In addition, they can provide tips on how to reduce side effects. Make sure to ask them, it is free advice.
Severe side effects
Although mupiriocin is unlikely to cause side effects, make sure to contact your doctor if you notice any of the following.
- Severe burning or stinging at the application site.
- Severe itching or rash at the application site or anywhere else.
- Peeling or blistering of the skin.
Other infections as side effects
Clostridium difficile (C. diff)
Even though mupirocin is not absorbed when used topically, it can have some absorption if in the open wound or used nasally. This allows for the potential for an infection called C. diff, which is an intestinal condition. Bacterial overgrowth with clostridium difficile occurs because of other bacteria being killed. As a result, this can cause severe diarrhea and stomach pain.
If you have those types of symptoms or see bloody watery stools, contact your doctor right away. This type of diarrhea won’t just go away, so make sure you take this seriously.
When mupirocin kills bacteria causing an infection it could be killing good bacteria on areas near the infection as well. As a result, fungi could invade and take over causing an infection. As mentioned mupirocin is not effective at treating any types of fungus. Therefore, ask your doctor about signs to be aware of for fungal infections based on the body area mupirocin is being applied to.
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Share your story!
Have you used mupirocin due to a skin infection? Did it work for you? Please chime in below with your comments and thoughts below.