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OnabotulinumtoxinA Injection

Generic name: OnabotulinumtoxinA Injection (oh nuh BOT yoo lin num TOKS in aye)
Brand name: Botox
Drug class: Skeletal muscle relaxants

Medically reviewed by Last updated on Dec 26, 2020.


  • Very bad side effects have happened when onabotulinumtoxinA injection has spread from where it is being used. These signs can happen within hours up to weeks after the shot. Swallowing and breathing problems can cause death. The risk is greatest in children with current muscle problems. Call your doctor right away if you have blurred eyesight, change in voice, drooping eyelids, or loss of strength or weakness all over the body. Call your doctor right away if you are not able to control your bladder, are seeing double, or have trouble breathing, speaking, or swallowing.

Uses of OnabotulinumtoxinA Injection:

  • It is used to lower underarm sweating.
  • It is used to prevent migraine headaches.
  • It is used to treat muscle problems around the eye.
  • It is used to treat muscle problems that lead to spasms.
  • It is used to treat spasms of the neck.
  • It is used to treat an overactive bladder.
  • It is used to treat bladder spasms.

What do I need to tell my doctor BEFORE I take OnabotulinumtoxinA Injection?

For all uses of onabotulinumtoxinA injection:

  • If you are allergic to onabotulinumtoxinA injection; any part of onabotulinumtoxinA injection; or any other drugs, foods, or substances. Tell your doctor about the allergy and what signs you had.
  • If you have an infection where the shot will be given.

For loss of bladder control:

  • If you have a urinary tract infection.
  • If you have trouble passing urine.

This is not a list of all drugs or health problems that interact with onabotulinumtoxinA injection.

Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take onabotulinumtoxinA injection with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.

What are some things I need to know or do while I take OnabotulinumtoxinA Injection?

For all uses of onabotulinumtoxinA injection:

  • Tell all of your health care providers that you take onabotulinumtoxinA injection. This includes your doctors, nurses, pharmacists, and dentists.
  • Talk with your doctor if you have had a botulinum toxin product in the last 3 or 4 months.
  • Avoid driving and doing other tasks or actions that call for you to be alert or have clear eyesight until you see how onabotulinumtoxinA injection affects you.
  • When onabotulinumtoxinA injection has been used for reasons it has not been approved for, very bad side effects like feeling very weak and trouble swallowing have happened. Sometimes, these very bad side effects have been deadly. Most of the time, people already had trouble swallowing or other health problems. Talk with the doctor.
  • This medicine is made from human plasma (part of the blood) and may have viruses that may cause disease. This medicine is screened, tested, and treated to lower the chance that it carries an infection. Talk with the doctor.
  • Tell your doctor if you are pregnant, plan on getting pregnant, or are breast-feeding. You will need to talk about the benefits and risks to you and the baby.

For loss of bladder control:

  • If you are 65 or older, use onabotulinumtoxinA injection with care. You could have more side effects.

How is this medicine (OnabotulinumtoxinA Injection) best taken?

Use onabotulinumtoxinA injection as ordered by your doctor. Read all information given to you. Follow all instructions closely.

  • It is given as a shot.

What do I do if I miss a dose?

  • Call the doctor for an office visit.

What are some side effects that I need to call my doctor about right away?

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

For all uses of onabotulinumtoxinA injection:

  • Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
  • Signs of infection like fever, chills, very bad sore throat, ear or sinus pain, cough, more sputum or change in color of sputum, pain with passing urine, mouth sores, or wound that will not heal.
  • Change in eyesight, eye pain, or very bad eye irritation.
  • If bright lights bother your eyes.
  • Drooping eyebrows.
  • Dizziness or passing out.
  • Seizures.
  • Heart attack and abnormal heartbeats have happened after use of onabotulinumtoxinA injection. Sometimes, this has been deadly. Call your doctor right away if you have chest pain or pressure, or an abnormal heartbeat.

For loss of bladder control:

  • Signs of a urinary tract infection (UTI) like blood in the urine, burning or pain when passing urine, feeling the need to pass urine often or right away, fever, lower stomach pain, or pelvic pain.
  • Trouble passing urine.

What are some other side effects of OnabotulinumtoxinA Injection?

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.

You may report side effects to the FDA at 1-800-332-1088. You may also report side effects at

If OVERDOSE is suspected:

If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

How do I store and/or throw out OnabotulinumtoxinA Injection?

  • If you need to store onabotulinumtoxinA injection at home, talk with your doctor, nurse, or pharmacist about how to store it.

Consumer information use

  • If your symptoms or health problems do not get better or if they become worse, call your doctor.
  • Do not share your drugs with others and do not take anyone else's drugs.
  • Keep all drugs in a safe place. Keep all drugs out of the reach of children and pets.
  • Throw away unused or expired drugs. Do not flush down a toilet or pour down a drain unless you are told to do so. Check with your pharmacist if you have questions about the best way to throw out drugs. There may be drug take-back programs in your area.
  • This medicine comes with an extra patient fact sheet called a Medication Guide. Read it with care. Read it again each time onabotulinumtoxinA injection is refilled. If you have any questions about onabotulinumtoxinA injection, please talk with the doctor, pharmacist, or other health care provider.
  • If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

Frequently asked questions

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.