Pronunciation: Boe-tox
Generic name: onabotulinumtoxinA
Dosage form: injection for intramuscular, intradetrusor, or intradermal use
Drug class: Skeletal muscle relaxants

Medically reviewed by Carmen Pope, BPharm. Last updated on Jan 15, 2025.

What is Botox?

Botox is an FDA-approved treatment for chronic migraines, excessive sweating, bladder conditions, eye muscle disorders including strabismus, and certain other muscle spasms. Botox Cosmetic is a botulinum toxin A treatment for anti-aging that temporarily improves the look of facial wrinkles and platysma bands. Although both these medicines contain botulinum toxin A (onabotulinumtoxinA), they are not interchangeable (see What is the difference between Botox and Botox Cosmetic?).

• This guide covers Botox for medical use. See Botox Cosmetic for aesthetic uses of botulinum toxin A.

Botox begins relaxing targeted muscles within 24 to 48 hours after injection. Maximum muscle relaxation and full results are seen around 2 weeks after an injection. Effects gradually wear off after 3 to 9 months as nerve signals recover or nerves regenerate and muscle function recovers.

FDA-approved Botox indications

Botox for medical use is FDA-approved for:

• treat overactive bladder symptoms, such as urinary urgency, frequency, or incontinence, in adults when anticholinergics do not work well enough or cannot be taken
• treat urinary incontinence in adults with an overactive bladder due to neurologic disease when anticholinergics do not work well enough or cannot be taken
• treat overactive bladder due to a neurologic disease in children 5 years of age and older when anticholinergics do not work well enough or cannot be taken
• prevent headaches in adults with chronic migraine who have 15 or more days each month with headaches lasting 4 or more hours each day
• treat increased muscle stiffness in people 2 years of age and older with spasticity
• treat the abnormal head position and neck pain that happens with cervical dystonia (CD) in adults
• treat certain types of eye muscle problems (strabismus) or abnormal spasms of the eyelids (blepharospasm) in people 12 years of age and older
• treat the symptoms of severe underarm sweating (severe primary axillary hyperhidrosis) when topical treatments do not work well enough.

Botox may also be referred to as Botox Therapeutic.

There is no Botox generic, but there are several other types of botulinum toxin available (such as Botox Cosmetic, Daxxify, Dysport, Jeuveau, Letybo, Myobloc, and Xeomin) each with different FDA-approved uses (see What is botulinum toxin used to treat?).

How Botox works medically

Therapeutic Botox is a neurotoxin that temporarily blocks nerve signals to specific muscles or sweat glands. This targeted approach:

• Relaxes muscles
• Eliminates or reduces muscle spasms
• Improves bladder capacity and incontinence symptoms
• Improves eye alignment
• Prevents migraines
• Inactivates overactive sweat glands, reducing sweating.

Botox wears off with time as new nerve endings sprout and gradually reconnect with muscles or sweat glands, allowing them to work normally again in the treated area.

Botox safety for medical conditions

Botox for medical conditions should only be injected by trained healthcare provider who can ensure:

• Sterile conditions
• Proper dosing and injection techniques to minimize side effects
• Comprehensive pre-treatment consultation
• Detailed aftercare instructions
• Regular follow-up care.

Botox side effects

The most common side effects of Botox for medical use are as follows.

At the injection site:

• Bruising, pain, redness, or swelling
• Numbness or tenderness
• Small bumps or marks that typically resolve within a few hours to days
• Infection at the injection site.

General side effects (these vary depending on the medical condition being treated):

• dry mouth
• tiredness
• headache
• neck pain
• mild weakness in the treatment area
• eye problems in those being treated with Botox for strabismus: double vision, blurred vision, decreased eyesight, drooping eyelids/eyebrows, swelling of your eyelids, and dry eyes
• allergic reactions, which may include symptoms such as itching, rash, red itchy welts, wheezing, asthma symptoms, or dizziness or feeling faint. Tell your doctor or get medical help right away if you are wheezing or have asthma symptoms, or if you become dizzy or faint upper respiratory tract infection.

Other common side effects experienced by those being treated with Botox for bladder conditions are:

• urinary tract infection in both children and adults
• painful urination in adults
• bacteria, white blood cells, and blood in the urine of children
• inability to empty your bladder on your own.

If you have difficulty fully emptying your bladder after getting Botox, you may need to use disposable self-catheters to empty your bladder up to a few times each day until your bladder can start emptying again.

Most of these side effects are temporary and resolve within a few days to weeks.

Serious side effects and warnings

Rarely, Botox can cause serious side effects that require immediate medical attention. It carries a Boxed Warning for the distant spread of the toxin effect. These problems can happen hours, days, to weeks after an injection.

Spread of toxin effects. In some cases, the effect of botulinum toxin A may affect areas of the body away from the injection site and cause symptoms of a serious condition called botulism. The symptoms of botulism include:

• loss of strength and muscle weakness all over the body
• double vision, blurred vision and drooping eyelids
• hoarseness or change or loss of voice (dysphonia)
• trouble saying words clearly (dysarthria)
• loss of bladder control
• trouble breathing
• trouble swallowing.

These problems could make it unsafe for you to drive a car or do other dangerous activities. There has not been a confirmed serious case of the spread of toxin effect away from the injection site when Botox has been used at the recommended dose to treat chronic migraine, severe underarm sweating, blepharospasm, or strabismus.

Problems swallowing, speaking, or breathing. These problems can happen hours, days, to weeks after an injection of Botox usually because the muscles that you use to breathe and swallow can become weak after the injection. Death can happen as a complication if you have severe problems with swallowing or breathing after treatment with Botox.

• People with certain breathing problems may need to use muscles in their neck to help them breathe. These people may be at greater risk for serious breathing problems with Botox.
• Swallowing problems may last for several months. People who cannot swallow well may need a feeding tube to receive food and water. If swallowing problems are severe, food or liquids may go into your lungs. People who already have swallowing or breathing problems before receiving Botox have the highest risk of getting these problems.

Call your healthcare provider or get emergency medical help if you have any of these problems after treatment with Botox:

• Difficulty swallowing, speaking, or breathing
• Vision problems
• Muscle weakness spreading beyond the injection site
• Allergic reactions (itching, rash, wheezing).

Tell your healthcare provider if you have any side effect that bothers you or that does not go away. These are not all the possible side effects of Botox. For more information, ask your doctor or pharmacist. Call your healthcare provider for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA1088.

Related/similar drugs

Before taking

It is not known whether medical Botox injections are safe and effective in people younger than:

• 18 years of age for treatment of chronic migraine, overactive bladder with urinary incontinence, or hyperhidrosis
• 5 years of age for the treatment of overactive bladder due to a neurologic disease
• 16 years of age for treatment of cervical dystonia
• 12 years of age for treatment of strabismus or blepharospasm
• 2 years of age for treatment of spasticity.

It is not known whether Botox is safe and effective:

• to prevent headaches in people with migraine who have 14 or fewer headache days each month (episodic migraine)
• for severe sweating anywhere other than your armpits.

Do not receive Botox if you:

• are allergic to any of the ingredients in Botox or Botox Cosmetic. See the end of this Guide for a complete list of ingredients in Botox and Botox Cosmetic
• had an allergic reaction to any other botulinum toxin product such as Myobloc (rimabotulinumtoxinB), Dysport (abobotulinumtoxinA), Xeomin (incobotulinumtoxinA), Jeuveau (prabotulinumtoxinA-xvfs), Daxxify (daxibotulinumtoxinA-lanm), or Letybo (letibotulinumtoxinA-wlbg). This may not be a complete list of all botulinum toxin products
• have a skin infection at the planned injection site.

Before receiving Botox, tell your healthcare provider about all your medical conditions, including if you:

• have a disease that affects your muscles and nerves (such as amyotrophic lateral sclerosis [ALS or Lou Gehrig's disease], myasthenia gravis or Lambert-Eaton syndrome)
• have allergies to any botulinum toxin product
• had any side effects from any botulinum toxin product in the past
• have or have had a breathing problem, such as asthma or emphysema
• have or have had swallowing problems
• have or have had bleeding problems
• have plans to have surgery
• had surgery on your face
• have drooping eyelids
• have any other change in the way your face normally looks
• are pregnant or plan to become pregnant
• are breastfeeding or plan to breastfeed.

Pregnancy

It is not known if Botox can harm your unborn baby.

Breastfeeding

It is not known if Botox passes into breast milk.

How will I receive Botox?

Botox is an injection a healthcare provider or a licensed professional will give you.

• This treatment is injected into the affected muscles, skin, or bladder.
• Your healthcare provider may change your dose of Botox until they find the best dose for you.
• Your healthcare provider will tell you how often you will receive your injections.

What should I avoid while receiving Botox?

Botox may cause loss of strength or general muscle weakness, vision problems, or dizziness within hours to weeks of receiving the injection. If this happens, do not drive a car, operate machinery, or do other dangerous activities.

What other drugs affect Botox?

Tell your doctor about all your medicines, including prescription and over-the-counter medicines, vitamins and herbal supplements. Using Botox with certain other medicines may cause serious side effects. Do not start any new medicines until you have told your doctor that you have received Botox in the past. Especially tell your doctor if you:

• have received any other botulinum toxin product in the last four months
• have received injections of botulinum toxin, such as Myobloc (rimabotulinumtoxinB), Dysport (abobotulinumtoxinA), Xeomin (incobotulinumtoxinA), Jeuveau (prabotulinumtoxinA-xvfs), Daxxify (daxibotulinumtoxinA-lanm), or Letybo (letibotulinumtoxinA-wlbg) in the past. This may not be a complete list of all botulinum toxin products. Be sure your doctor knows exactly which product you received
• have recently received an antibiotic by injection
• take muscle relaxants
• take an allergy or cold medicine
• take a sleep medicine.
• take anti-platelets (aspirin-like products) or anti-coagulants (blood thinners).

Ask your doctor if you are not sure if your medicine is listed above. Know the medicines you take. Keep a list of your medicines with you to show your doctor and pharmacist each time you get a new medicine.

Ingredients

The ingredients in Botox and Botox Cosmetic are the same.

Active ingredient: onabotulinumtoxinA

Inactive ingredients: human albumin and sodium chloride.

Manufacturer

Botox and Botox Cosmetic are made by AbbVie, who acquired the previous manufacturer Allergan in 2020. Both forms contain the same active ingredient (onabotulinumtoxinA) but are approved for different uses.

Notable drugs from AbbVie include:

• Humira (arthritis, psoriasis, Crohn's disease)
• Vraylar (schizophrenia, bipolar disorder)
• Juvederm (dermal fillers)
• Ubrelvy (migraine)
• Rinvoq (rheumatoid arthritis)
• Skyrizi (psoriasis)

AbbVie also owns Restasis (for dry eyes) and a line of aesthetic products like Kybella (fat reduction) and CoolSculpting. Before the merger, AbbVie was best known for Humira, which was for many years the world's best-selling drug.

Botox Biosimilars

Biosimilar and interchangeable products are biological products that are highly similar to and have no clinically meaningful differences from the reference product.

Reference products

These are biological products that have already been approved by the FDA, against which biosimilar products are compared. There are 2 for Botox.

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Further information

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

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