Specifically, the Food and Drug Administration (FDA) has approved Bactrim oral tablet for:
This article describes possible side effects of Bactrim. You can explore this overview article to learn more about Bactrim, including the drug’s uses, side effects, and more.
Bactrim is a brand-name medication that comes as a tablet that you swallow by mouth. It also comes as double-strength oral tablets, under the brand name Bactrim DS. Bactrim and Bactrim DS are available in a generic version called sulfamethoxazole/trimethoprim. This article describes possible side effects of Bactrim.
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More common side effects of Bactrim
Bactrim oral tablet may cause mild or serious side effects. Below are some of the more common side effects of this medication.
Commonly reported side effects of Bactrim include:
Mild side effects of Bactrim
Bactrim may cause certain mild side effects. Most often, mild side effects are temporary and can be easily managed. Tell your doctor or pharmacist if you have side effects that don’t go away or become bothersome.
Mild side effects of Bactrim oral tablet that occurred in studies include:
* To learn more about this side effect, see the “Side effects of Bactrim in detail” section below.
Bactrim oral tablet may cause more mild side effects than those listed above. For details, see the drug’s prescribing information.
Serious side effects of Bactrim
Bactrim may rarely cause certain serious side effects. If you have any serious side effects from Bactrim oral tablet, call your doctor right away. But if you think you’re having a medical emergency or your side effects feel life threatening, take immediate action. Call 911 or a local emergency number, or go to the nearest emergency room.
After the FDA approves a drug, it tracks and reviews side effects of the medication. Visit MedWatch’s website if you’d like to notify the FDA about a side effect you’ve had with Bactrim.
Serious side effects of Bactrim oral tablet that occurred in studies include:
* To learn more about this side effect, see the “Side effects of Bactrim in detail” section below.
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Common questions about side effects of Bactrim
Here are answers to some common questions about side effects of Bactrim oral tablet. If you have other questions, talk with your doctor or pharmacist.
How long do side effects of Bactrim usually last?
It depends on several factors, including the specific side effect, why you’re taking Bactrim oral tablet, and how long you take it. Most common side effects of Bactrim oral tablet are temporary and go away on their own, especially if you take the drug for a short time.
Some side effects could occur after you stop taking Bactrim oral tablet. For example, C. diff diarrhea* can occur more than 2 months after taking an antibiotic, such as Bactrim.
Tell your doctor or pharmacist if you have side effects that don’t go away or are bothersome. Your doctor or pharmacist can discuss possible ways to manage any side effects. They can also help decide whether a possible side effect is due to Bactrim or another cause.
In rare cases, Bactrim oral tablet may cause long-term side effects. To learn more, see the question below, “Does Bactrim cause long-term side effects” or talk with your doctor.
* To learn more about this side effect, see the “Side effects of Bactrim in detail” section below.
Is Bactrim safe for older adults?
Possibly. But older adults (people ages 65 years and older) may be at a higher risk of severe side effects with Bactrim oral tablet, especially if they have:
Older adults who take certain other medications may also be at higher risk of severe side effects with Bactrim oral tablet. This includes older adults who take drugs such as:
Certain serious side effects, such as a high blood potassium level*, severe skin reactions*, and certain blood disorders have been reported in older adults.
Talk with your doctor if you’re concerned about whether Bactrim is safe for you. Your doctor can discuss the risks and benefits of using Bactrim oral tablet or another antibiotic to treat your condition. They may also do bloodwork if you’re taking certain other drugs with Bactrim.
* To learn more about this side effect, see the “Side effects of Bactrim in detail” section below.
Does Bactrim cause long-term side effects?
Yes, in rare cases Bactrim oral tablet may cause long-term side effects. These may last for a while after you’ve stopped taking the drug. But most common side effects of Bactrim oral tablet are temporary and go away on their own, especially if you take the drug for a short time.
Some serious side effects*, if they occur, could affect your health long-term. Examples of long-term side effects reported with Bactrim oral tablet include:
Talk with your doctor or pharmacist to learn more about these side effects and how to manage them. Ask your doctor or pharmacist for more information about how long these side effects of Bactrim oral tablet may last.
* For more information about the serious side effects of Bactrim, see the “Serious side effects of Bactrim” section above.
† To learn more about this side effect, see the “Side effects of Bactrim in detail” section below.
Side effects of Bactrim in detail
Below you’ll find details on some of the side effects of Bactrim oral tablet.
Severe skin reactions
In studies, severe skin reactions were rare in people taking Bactrim oral tablet. These reactions are serious and can be life threatening. Severe skin reactions that may occur with Bactrim oral tablet include:
With a severe skin reaction, early symptoms can occur before a severe reaction. These may include:
Certain factors can increase the risk of some severe skin reactions with Bactrim oral tablet. These include older age, and having HIV, cancer, or a weakened immune system. Some people of Southeast Asian, Chinese, and Indian descent may also be at higher risk. Or you may be at higher risk if an immediate family member has had a severe skin reaction.
Ways to manage
Severe skin reactions can be a life threatening medical emergency. Tell your doctor right away if you have a rash or other early symptoms of a severe skin reaction. For severe allergic reaction symptoms, such as swelling or trouble breathing, call 911 or your local emergency number. Be sure to tell your doctor or other healthcare professionals about all medications you take. Your doctor will have you stop taking Bactrim if you have a severe skin reaction.
Tell your doctor before starting Bactrim if you or a family member has had a severe skin reaction in the past. You may be at higher risk of having another reaction. Also, tell your doctor if you have any other risk factors noted above for severe skin reactions.
High blood potassium level
In studies, high blood potassium level (hyperkalemia) was seen in people taking Bactrim oral tablet. It may be more common with higher doses, but can also occur at usual doses. This side effect may be serious.
With a high blood potassium level, you may not experience any symptoms until your potassium levels are very high. These symptoms can include heart palpitations or irregular heart rate, weakness, or a feeling of numbness or tingling.
Certain factors can increase the risk of a high blood potassium level with Bactrim oral tablet. The risk may be higher in older adults and in people who have:
Ways to manage
The effects of high potassium can be serious, so it’s important to call your doctor right away if you have symptoms of a high potassium level. The actions your doctor will recommend you take will depend on your level of potassium in your blood. In some cases, you may need to go to the hospital. For severe symptoms, call 911 or your local emergency number.
Depending on your risk for having a high blood potassium level, your doctor may do blood tests before prescribing Bactrim or during your treatment with it. Or they may choose a different antibiotic to treat your condition.
C. diff diarrhea
In studies, C. diff diarrhea was reported in people taking Bactrim oral tablet. C. diff diarrhea is reported with nearly all other antibiotics as well. This side effect can be mild to serious. In rare cases, it can be life threatening.
C. diff is a type of bacterium. If you have too much of it in your intestines, it can lead to an infection and inflammation of your colon. Usually, other bacteria in the intestines help manage the amount of C. diff. But when the other bacteria are killed by an antibiotic, including Bactrim, the amount of C. diff in your intestines can go up. C. diff makes toxins, which can lead to diarrhea.
Diarrhea is the main symptom of a C. diff infection. You may also have other symptoms, such as:
Certain factors can also increase the risk of C. diff diarrhea with Bactrim. These include:
- older age (people ages 65 years and older)
- recently being in a hospital or nursing home
- having a weakened immune system
- previous C. diff infection
Ways to manage
If you have frequent or severe diarrhea while taking Bactrim oral tablet, or if your symptoms last more than a couple of days, call your doctor right away. Get immediate medical care if you see blood in your stool or have severe stomach pain. If you have C. diff diarrhea, your doctor may have you stop taking Bactrim. You may also need fluids or antibiotics to treat C. diff.
Although diarrhea is a common side effect of antibiotics, it usually ends when you finish the antibiotic. But C. diff diarrhea can occur more than two months after taking an antibiotic. Let your doctor know about all medications you’ve taken if you develop C. diff diarrhea.
For some people, Bactrim oral tablet can cause an allergic reaction.
Symptoms can be mild or serious, and they may include:
- itchiness
- skin rash
- swelling under the skin, usually affecting eyelids, lips, hands, or feet
- swelling of the mouth, tongue, or throat, which can make it hard to breathe
- flushing (temporary warmth, redness, or deepening of skin color)
In rare cases, serious allergic reactions with Bactrim can include severe skin reactions*, such as:
* See the “Severe skin reactions” section above to learn more.
Ways to manage
For mild allergic reaction symptoms, such as a mild rash, call your doctor right away. They may recommend treatments to help manage your symptoms. They’ll also let you know whether you should keep taking the medication.
For severe allergic reaction symptoms, such as swelling or trouble breathing, call 911 or your local emergency number right away. These symptoms require immediate medical care because they can become life threatening. If you’ve had a serious allergic reaction to Bactrim, your doctor may recommend taking a different medication instead.
Warnings for Bactrim
Below are some factors you may want to discuss with your doctor before taking Bactrim oral tablet.
Warnings
It may not be safe for you to take Bactrim oral tablet if you have specific health conditions. These are sometimes called drug-condition interactions. Other things may also affect whether Bactrim oral tablet is a safe treatment option for you.
Before taking Bactrim oral tablet, tell your doctor about your health and medications you take. Things to consider include:
* See the “Side effects of Bactrim in detail” section above to learn more.
Bactrim and pregnancy
Bactrim oral tablet is typically not taken during pregnancy.
If you’re planning a pregnancy or can become pregnant, talk with your doctor before taking this medication. Your doctor may suggest birth control options to use during treatment with Bactrim.
Bactrim and breastfeeding
Bactrim oral tablet may not be safe to take while breastfeeding, especially when breastfeeding premature, ill, or stressed newborns, or infants who have jaundice. Bactrim passes into breast milk and it’s not recommended for infants ages under 2 months.
If you’re currently breastfeeding or planning to do so, talk with your doctor before taking this medication. Your doctor may recommend other ways to feed your child during treatment with Bactrim.
Bactrim oral tablet isn’t known to interact with alcohol. But drinking alcohol with antibiotics may increase your chance of side effects such as nausea or diarrhea. Alcohol may also interfere with your body’s ability to heal from an infection.
Long-term use of alcohol may also increase the risk of folate deficiency (a type of B vitamin). Note that Bactrim should be avoided in people with a possible folate deficiency.
If you drink alcohol, talk with your doctor about whether it’s safe to consume it during your treatment with Bactrim.
What to ask your doctor
This article describes common and serious side effects of Bactrim oral tablet. If your doctor prescribes this medication, they can discuss possible side effects with you. Let your doctor know if you have concerns or questions about treatment with this medication.
Here’s a list of some possible questions you may want to ask your doctor:
- Is it safe for older adults to take Bactrim?
- Is my risk of side effects with Bactrim higher based on my medical conditions?
- Can other medications that I take increase my risk of side effects with Bactrim?
- How long do side effects of Bactrim usually last?
- Does Bactrim cause long-term side effects?
Disclaimer: Optum Perks has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.
