Botox (onabotulinumtoxinA) is a prescription drug that’s used to treat a variety of medical conditions. Botox comes as a powder that’s mixed with liquid to form a solution, which is injected.

Botox is used for medical purposes in adults and some children. Some of its uses include:

To learn more, see “What is Botox used for?” directly below.

Botox basics

The active drug in Botox is called onabotulinumtoxinA, which is a biologic medication. A biologic is made from parts of living organisms. Botox’s active drug is not available in a biosimilar form. (Biosimilars are like generic drugs. But unlike generics, which are made for nonbiologic drugs, biosimilars are made for biologic drugs.)

Note: In this article, we describe Botox that’s used for medical purposes. To learn more about Botox that’s used for cosmetic reasons, check out this article.

If you have certain conditions, your doctor may recommend Botox. It’s used for:

With these conditions, your nerves send signals that cause symptoms such as muscle contractions, sweating, or pain. Botox works by preventing your nerves from sending signals that trigger these symptoms.

It’s important to note that Botox is not used to treat:

  • episodic migraine (in which migraine episodes occur on 14 or fewer days per month)
  • excessive sweating in areas other than the armpit

* For this use, Botox can be prescribed for people who can’t take anticholinergic drugs or whose condition didn’t respond to anticholinergic drugs.

Like most drugs, Botox may cause mild or serious side effects. The lists below describe some of the more common side effects. These lists don’t include all possible side effects. Side effects from Botox can be different for each of the drug’s uses.

Your doctor or pharmacist can tell you more about the potential side effects of Botox. They can also suggest ways to help reduce side effects.

Mild side effects

Here’s a list of some of the mild side effects that Botox can cause. To learn about other mild side effects, talk with your doctor or pharmacist, or read Botox’s prescribing information.

Side effects of Botox can vary depending on where the drug is injected. Mild side effects can include:

Mild side effects of many drugs may go away within a few days or a couple of weeks. But if they become bothersome, talk with your doctor or pharmacist.

* For more information about this side effect, see the “Side effect focus” section below.

Serious side effects

Serious side effects from Botox can occur, but they aren’t common. If you have serious side effects from Botox, call your doctor right away. But if you think you’re having a medical emergency, you should call 911 or your local emergency number.

Serious side effects can include:

* For more information about this side effect, see the “Side effect focus” section below.
† In studies, overreaction of the nervous system was more likely in people receiving Botox for loss of bladder control that’s related to a disorder of the nervous system.

Side effect focus

Learn more about some of the side effects Botox may cause below.

Pain after injection

You may have some pain after receiving Botox injections. In fact, this was a common side effect in studies of the drug. The pain typically occurs around Botox injection sites, which could include areas on your back, neck, arms, or legs.

What might help

To help relieve pain after Botox injections, try the following:

  • avoid rubbing or massaging the skin around or on the injection site
  • use a cold compress on the injection site
  • take over-the-counter medications such as acetaminophen (Tylenol) or ibuprofen (Advil)

If you have pain that’s severe or bothersome after getting Botox injections, talk with your doctor.

Spread of toxin effects

Botox has a boxed warning about the risk of the spread of toxin effects. A boxed warning is the most serious warning from the Food and Drug Administration (FDA).

When it’s injected into your body, Botox may spread outside of the area where you receive the injection. This side effect is called “spread of toxin effects.” And it can lead to symptoms that are similar to botulism poisoning. These symptoms may include:

These symptoms might happen within hours of getting a Botox injection. Or, they might not happen until weeks after you’ve had a Botox injection. Your risk of having trouble breathing or trouble swallowing is higher if you already have either breathing or swallowing problems.

What might help

If you have any of the symptoms listed above after getting a Botox injection, tell your doctor right away. Call 911 or your local emergency number if your symptoms feel life threatening.

Urinary tract infection

You might get a urinary tract infection (UTI) after getting Botox. In studies, this side effect was more common in people who received Botox to treat overactive bladder than in people receiving the drug for other conditions.

A few possible symptoms of UTI include:

What might help

If you have any UTI symptoms after getting a Botox injection, tell your doctor. Prescription drugs such as antibiotics, antivirals, or antifungals are usually needed to treat UTIs. But to help lessen UTI symptoms, you can also try home remedies such as drinking water and cranberry juice.

Allergic reaction

Some people may have an allergic reaction to Botox. Symptoms of a mild allergic reaction can include:

  • rash
  • itchiness
  • flushing (temporary warmth, redness, or deepening of skin color)

A more severe allergic reaction is rare but possible. Symptoms of a severe allergic reaction can include swelling under your skin, typically in your eyelids, lips, hands, or feet. They can also include swelling of your tongue, mouth, or throat, which can cause trouble breathing.

Call your doctor right away if you have an allergic reaction to Botox. Call 911 or your local emergency number if your symptoms feel life threatening.

Find answers to some commonly asked questions about Botox.

How long does it take Botox to work?

Botox starts working within 1–3 days after it’s injected into your body. However, it might be several weeks after your injection before you notice your condition improving.

Is Botox used for tension headaches?

Yes, Botox is sometimes prescribed to treat tension headaches. But Botox isn’t approved to treat tension headaches, so this is known as off-label use.

If you have questions about treatment options for tension headaches, talk with your doctor.

How often can you get Botox injections?

How often you’ll be able to get Botox injections depends on the condition it’s being used to treat. In general, you’ll get Botox injections only once every 3 months.

Your doctor will recommend the dosage of Botox that’s right for you. Below are commonly used dosages, but the dosage you receive will be determined by your doctor.

Forms and strengths

Botox is given as an injection into your body by a healthcare professional. For most of its uses, you’ll get Botox as an injection into a muscle or into multiple muscles. But the type of injection and exact injection sites vary depending on the condition you’re receiving the drug for. See “How is Botox given?” below for details.

Botox comes as a powder inside vials. The powder is mixed with liquid to make a solution for injection. The drug is available in two strengths: 100 units and 200 units.

Recommended dosage

How often you’ll get Botox injections depends on the condition you’re receiving the drug for. You’ll usually get Botox injections no more than once every 3 months.

For more information about the dosages of Botox for the conditions it’s used for, see this article.

Questions about Botox’s dosage

Below are some common questions about Botox’s dosage.

  • What if I miss a dose of Botox? Call your doctor’s office to reschedule any missed appointments for Botox injections. The staff at your doctor’s office can help you set up another appointment.
  • Will I need to receive Botox long term? Yes, in most cases, you’ll receive Botox long term for your condition. But be sure to talk with your doctor about this.
  • How long does Botox take to work? Botox starts working within a few days after it’s been injected into your body. But it might be several weeks after the injection before you notice your condition improving.

Your doctor will explain how Botox is given. They’ll also explain how often you should get Botox for your condition. Be sure to follow your doctor’s instructions for when to receive Botox.

Getting Botox

Botox comes as a powder inside vials. The powder is mixed with liquid to make a solution that’s injected into your body. You’ll get Botox injections from a healthcare professional.

For most uses, you’ll get Botox as an injection into the muscle. But the type of injection and exact injection sites for Botox vary depending on the condition you’re receiving the drug for.

For example, for migraine episode prevention, you’ll get Botox in these injection sites:

  • your forehead
  • your temples
  • back of your head
  • base of your neck
  • between your shoulders

But injection sites for overactive bladder (OAB) are very different. For OAB, you’ll get Botox injections directly into your bladder.

Botox and food

Botox is given as an injection. You can get Botox with or without having eaten any food.

Below are a few important considerations to keep in mind before you take Botox.

Interactions

Taking medications, vaccines, foods, and other things with a certain drug can affect how the drug works. These effects are called interactions.

Before receiving Botox, be sure to tell your doctor about all medications you take (including prescription and over-the-counter types). Also, describe any vitamins, herbs, or supplements you use. Your doctor or pharmacist can tell you about any interactions these items may cause with Botox.

Interactions with drugs or supplements

Botox can interact with several types of drugs, including:

This list doesn’t contain all types of drugs that may interact with Botox. Your doctor or pharmacist can tell you more about these interactions and any others that may occur with use of Botox.

Boxed warning

Botox has a boxed warning. A boxed warning is the most serious warning from the Food and Drug Administration (FDA) about drug effects that may be dangerous.

Botox may spread outside of the area where you receive the injection. This side effect is called spread of toxin effects. It can lead to symptoms that are similar to botulism poisoning. These symptoms may include:

For details, see the “What are Botox’s side effects?” section above.

Other warnings

Botox may not be right for you if you have certain medical conditions or other factors that affect your health. Talk with your doctor about your health history before you start Botox. Factors to consider include those described below.

Infection at an injection site. If you have an infection in an area where you’re planning to have a Botox injection, you should not get the planned injection. Talk with your doctor about any infections you have before getting Botox.

Neuromuscular disorders. Before getting Botox, tell your doctor about any neuromuscular disorders you have, such as myasthenia gravis. If you have a neuromuscular disorder, you might have a higher risk of certain side effects with Botox. For instance, you may have a higher risk of double vision, drooping eyelid, trouble breathing, and trouble swallowing. If you get Botox while you have a neuromuscular disorder, your doctor will likely monitor you closely for these side effects.

Trouble breathing or swallowing. If you have trouble breathing or swallowing, you might be more likely to have these side effects during Botox treatment. Be sure to tell your doctor about any breathing or swallowing conditions you have before starting this drug.

Trouble emptying your bladder. You shouldn’t receive Botox to treat loss of bladder control if you aren’t able to completely empty your bladder on your own. But you can typically receive Botox if you have this condition and you use a catheter to empty your bladder. Talk with your doctor before starting Botox if you have problems with emptying your bladder.

Allergic reaction. If you’ve had an allergic reaction to Botox or any of its ingredients, your doctor won’t prescribe Botox. Ask your doctor what other medications are better options for you.

Use with alcohol

There aren’t any known issues with drinking alcohol during Botox treatment.

Keep in mind that alcohol can make you bleed more easily than usual. And bleeding is a possible side effect of Botox injections. You may need to avoid drinking alcohol for a few days before your injections.

If you drink alcohol, talk with your doctor about the amount that’s safe for you to drink during Botox treatment.

Pregnancy and breastfeeding

It isn’t known if Botox is safe to receive during pregnancy or while breastfeeding. If you have questions about receiving this drug while you’re pregnant or breastfeeding, talk with your doctor.

Costs of prescription drugs can vary depending on many factors. These factors include your treatment plan, your insurance coverage, and other factors. To find current prices for Botox injections in your area, talk with your doctor.

You won’t pick up Botox from a pharmacy. The drug is only sold by specialty pharmacies, and you’ll get Botox injections at your doctor’s office.

You can visit the Botox website to view possible support options, including a Botox savings program.

If you have questions about how to pay for your treatment, you can talk with your doctor or pharmacist.

Before starting Botox, talk with your doctor about whether this drug is right for you. You may want to ask your doctor about treatments other than Botox for your condition.

Here are a few questions you may want to ask your doctor:

  • Is it safe for my child to receive Botox?
  • Will symptoms come back after stopping Botox?
  • What should I do to prepare for Botox injections?

To learn more about Botox, see these articles:

To get information on different conditions and tips for improving your health, subscribe to any of Healthline’s newsletters. You may also want to check out the online communities at Bezzy. It’s a place where people with certain conditions can find support and connect with others.

Q:

If I use Botox for cosmetic purposes, will it help prevent migraine episodes as well?

Anonymous

A:

It’s unlikely that cosmetic use of Botox will help prevent migraine episodes. The number of injection sites and the doses given are much higher for helping prevent migraine episodes than for cosmetic purposes.

There may be some similarities in the injection sites used. But the approved dose of Botox for migraine is 155 units given across seven different areas in your head and neck muscles. The approved dose of cosmetic Botox is 20–40 units given in the specific areas desired.

If you’re interested in receiving Botox to help prevent migraine episodes, talk with your doctor to see if Botox is right for you.

The Healthline Pharmacist TeamAnswers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.
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Disclaimer: Healthline 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.

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