moxifloxacin

• Risk factors: Age over 60 years | History of kidney, heart, or lung transplant | Kidney failure | History of tendon-related problems, such as rheumatoid arthritis (RA) | Taking steroids | High-intensity exercise

Fluoroquinolone antibiotics like moxifloxacin can raise the risk of swelling in your tendons (tendonitis). They can also raise the risk of tears in your tendons. Tendon problems most often happen to the Achilles tendon above your heel, but other tendons can also be affected. Tendon problems can start within hours or days of taking moxifloxacin. They can also happen several months after you stop treatment.

Tendon problems can happen at any age, but the risk is higher if you're over 60 years old. It's also higher for people with a kidney, heart, or lung transplant and those taking steroids. Be sure to tell your prescriber if you've had tendon problems in the past so they can check your risk.

Stop taking moxifloxacin and rest the affected area if you have tendon pain or swelling. Call your care team right away.

Fluoroquinolone antibiotics like moxifloxacin can raise the risk of peripheral neuropathy. This nerve damage can cause pain, burning, tingling, numbness, or weakness in your arms or legs. It can also change how you feel touch or temperature. These problems can start soon after treatment begins (within hours to weeks). They might not go away in some people.

Before starting moxifloxacin, tell your prescriber if you've had nerve problems before. You might need a different type of antibiotic.

If you develop signs of nerve damage during treatment, stop taking moxifloxacin and tell your care team right away.

• Risk factors: History of seizure | Medical conditions that raise the risk of seizures | Taking medications that raise the risk of seizures | Taking nonsteroidal anti-inflammatory drugs (NSAIDs)

Fluoroquinolone antibiotics like moxifloxacin can raise the risk of serious effects on your brain and nervous system. These can include seizures, dizziness, or tremors. It's happened within hours of weeks of starting treatment. Tell your prescriber if you have a brain or nervous system condition, such as epilepsy. They can check if moxifloxacin is safe for you. Stop taking moxifloxacin and get medical help right away if you have a seizure.

Moxifloxacin can also raise the risk of having changes in your mood, thoughts, or behavior. This can sometimes happen within hours to weeks after starting the medication. Examples include anxiety, confusion, hallucinations, trouble sleeping, depression, or thoughts of suicide. Stop taking moxifloxacin and get medical help right away if you notice any unusual changes in your mood, thoughts, or behavior.

If you have myasthenia gravis, moxifloxacin can make muscle weakness worse. Rarely, this can be serious and affect the muscles you use to breathe, causing trouble breathing. Tell your prescriber if you have myasthenia gravis. They'll likely choose a different type of antibiotic for you.

• Risk factors: Older adults | Known QT prolongation | Certain arrhythmias | Low potassium or magnesium levels | History of liver problems | Taking certain heart rhythm medications | Taking other medications that cause QT prolongation

Moxifloxacin can cause a serious heart rhythm problem called QT prolongation. This happens when your heart takes longer than usual to reset between beats.

Before starting moxifloxacin, tell your prescriber about your health conditions and medications. Your risk can be higher if you have certain heart rhythm problems or abnormal electrolyte levels. It can also be higher if you take other medications that can cause QT prolongation, such as amiodarone (Pacerone). Your prescriber can check if moxifloxacin is safe for you.

Call 911 right away if you have a pounding or irregular heartbeat, chest pain, trouble breathing, or severe dizziness. These can be signs of a serious heart rhythm problem.

It's possible for antibiotics like moxifloxacin to cause a serious allergic reaction, including anaphylaxis. Signs can include hives, swelling of the face, lips, or tongue, trouble breathing, or passing out. Get medical help right away if you have any of these symptoms.

Moxifloxacin can also cause rare but serious skin reactions. One example is Stevens-Johnson syndrome (SJS). Stop taking moxifloxacin and get medical help right away if you develop a rash, blisters, peeling skin, or fever.

Rarely, people taking fluoroquinolone antibiotics like moxifloxacin have had serious reactions in different parts of the body. These can affect your liver, kidneys, lungs, joints, or blood cells. Reactions can happen after taking several doses of the medication. Some can be severe or life-threatening.

Stop taking moxifloxacin and tell your care team right away if you have new or unusual symptoms. These can include yellow skin or eyes, fever, unusual bleeding or bruising, trouble breathing, or new muscle or joint pain.

• Risk factors: Older adults

Studies have found a higher risk of a bulge or tear in the aorta within 2 months after taking antibiotics like moxifloxacin. The aorta is the largest blood vessel in your body. This problem is rare but can be life-threatening. The risk might be higher in older adults, but it's not clear why it could happen.

Tell your prescriber if you've had an aortic aneurysm or other problems with your aorta. Because of this risk, your prescriber might choose a different antibiotic for you.

Call 911 or get medical help right away if you have sudden, severe pain in your chest, back, or stomach that doesn't go away. This can be a sign of a serious problem with your aorta.

Antibiotics, such as moxifloxacin, can change the normal bacteria in your gut. This can let harmful bacteria called Clostridioides difficile (C. diff) grow too much and cause a serious infection. This infection can lead to severe diarrhea, even up to 2 months after you stop the antibiotic.

It's important to know the difference between mild diarrhea from moxifloxacin and serious diarrhea from C. diff. Signs of a C. diff infection include fever, nausea, severe or watery diarrhea, foul-smelling diarrhea, frequent bowel movements, or bloody stool. Get medical help right away if you have any signs of this infectious diarrhea. This can be a medical emergency and should get treated as soon as possible.

• Risk factors: Diabetes | Older adults with diabetes | Taking diabetes medications

Moxifloxacin can cause changes in your blood sugar. It can make your blood sugar too low or too high. The risk can be higher if you have diabetes and take diabetes medications. Tell your prescriber if you have diabetes. You might need to check your blood sugar more often while taking moxifloxacin.

Watch for symptoms of low blood sugar. These can include feeling shaky, confused, nervous, or very hungry. You also might have a fast heartbeat, sweating, or chills. If this happens, stop taking moxifloxacin and get medical help right away. Low blood sugar should be treated right away.

Moxifloxacin makes your skin more sensitive to the sun and ultraviolet (UV) light. This means you can get sunburns more easily than usual. It might cause redness, burning, swelling, or blisters on skin exposed to the sun or UV light.

To lower your risk, protect your skin from the sun. Wear sunscreen and clothing that covers your skin when you're outside, even during the winter or on cloudy days. Also, avoid tanning beds and try not to spend too much time in direct sunlight.