Medically reviewed on April 26, 2017
What is onabotulinumtoxinA (Botox)?
OnabotulinumtoxinA (Botox), also called botulinum toxin type A, is made from the bacteria that causes botulism. Botulinum toxin blocks nerve activity in the muscles.
Botox is used to treat cervical dystonia (severe spasms in the neck muscles). Botox is also used to treat muscle spasms (stiffness) in the upper limbs (elbows, wrists, fingers) or lower limbs (ankles, toes). Botox is also used to treat severe underarm sweating (hyperhidrosis).
Botox is also used to treat certain eye muscle conditions caused by nerve disorders. This includes uncontrolled blinking or spasm of the eyelids, and a condition in which the eyes do not point in the same direction.
Botox is also used to prevent chronic migraine headaches in adults who have migraines for more than 15 days per month, each lasting 4 hours or longer. Botox should not be used to treat a common tension headache.
Botox Cosmetic is used to temporarily lessen the appearance of facial wrinkles.
Botox may also be used for other purposes not listed in this medication guide.
You should not use Botox if you have an infection in the area where the medicine will be injected. Botox should not be used for overactive bladder or incontinence if you have a bladder infection or you are unable to urinate (unless you routinely use a catheter).
The botulinum toxin contained in this medicine can spread to other body areas beyond where it was injected. This can cause serious life-threatening side effects.
Call your doctor at once if you have a hoarse voice, drooping eyelids, vision problems, severe muscle weakness, loss of bladder control, or trouble breathing, talking, or swallowing. Some of these effects can occur up to several hours or several weeks after an injection.
Before taking this medicine
You should not receive this medication if you are allergic to botulinum toxin, or if you have:
an infection in the area where the medicine will be injected; or
(for overactive bladder and incontinence) if you have a current bladder infection or if you are unable to urinate and you do not routinely use a catheter.
To make sure Botox is safe for you, tell your doctor if you have:
problems with swallowing;
facial muscle weakness (droopy eyelids, weak forehead, trouble raising your eyebrows);
a change in the normal appearance of your face;
if you have had or will have surgery (especially on your face);
if you have ever had a side effect after receiving a botulinum toxin in the past.
Botox is made from human plasma (part of the blood) which may contain viruses and other infectious agents. Donated plasma is tested and treated to reduce the risk of it containing infectious agents, but there is still a small possibility it could transmit disease. Talk with your doctor about the risks and benefits of using this medication.
It is not known whether this medicine will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.
Botox can pass into breast milk and may harm a nursing baby. Tell your doctor if you are breast-feeding a baby.
How is Botox given?
Botulinum toxin injections should be given only by a trained medical professional, even when used for cosmetic purposes.
This medicine is injected into a muscle. A doctor, nurse, or other healthcare provider will give you this injection. Botox injections should be spaced at least 3 months apart.
Your injection may be given into more than one area at a time, depending on the condition being treated.
While receiving botulinum toxin injections for an eye muscle conditions, you may need to use eye drops, ointment, a special contact lens or other device to protect the surface of your eye. Follow your doctor's instructions.
If you are being treated for excessive sweating, shave your underarms about 24 hours before you will receive your injection. Do not apply underarm antiperspirants or deodorants for 24 hours before you receive the injection. Avoid exercise and hot foods or beverages within 30 minutes before the injection.
It may take up to 2 weeks after injection before neck muscle spasm symptoms begin to improve. You may notice the greatest improvement at 6 weeks after injection.
It may take only 1 to 3 days after injection before eye muscle spasm symptoms begin to improve. You may notice the greatest improvement at 2 to 6 weeks after injection.
The effects of a Botox injection are temporary. Your symptoms may return completely within 3 months after an injection. After repeat injections, it may take less and less time before your symptoms return, especially if your body develops antibodies to the botulinum toxin.
Do not seek botulinum toxin injections from more than one medical professional at a time. If you switch healthcare providers, be sure to tell your new provider how long it has been since your last botulinum toxin injection.
Using this medication more often than prescribed will not make it more effective and may result in serious side effects.
What happens if I miss a dose?
Since botulinum toxin has a temporary effect and is given at widely spaced intervals, missing a dose is not likely to be harmful.
What happens if I overdose?
Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.
Overdose symptoms may not appear right away, but can include muscle weakness, trouble swallowing, and weak or shallow breathing.
What should I avoid after receiving Botox?
Botox may impair your vision or depth perception. Be careful if you drive or do anything that requires you to be able to see clearly.
Avoid using underarm antiperspirants or deodorants for 24 hours after a botulinum toxin injection if you are being treated for excessive underarm sweating.
Avoid going back to your normal physical activities too quickly after receiving an injection.
Botox side effects
Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; feeling like you might pass out; swelling of your face, lips, tongue, or throat.
The botulinum toxin contained in Botox can spread to other body areas beyond where it was injected. This has caused serious life-threatening side effects in some people receiving botulinum toxin injections, even for cosmetic purposes.
Call your doctor at once if you have any of these side effects, some of which can occur up to several hours or several weeks after an injection:
unusual or severe muscle weakness (especially in a body area that was not injected with the medication);
trouble breathing, talking, or swallowing;
loss of bladder control;
hoarse voice, drooping eyelids;
chest pain, irregular heartbeats;
pain or burning when you urinate, little or no urination;
sore throat, cough, chest tightness, shortness of breath; or
eyelid swelling, crusting or drainage from your eyes, problems with vision.
Common side effects may include:
trouble swallowing for several months after treatment;
muscle weakness near where the medicine was injected;
bruising, bleeding, pain, redness, or swelling where the injection was given;
increased sweating in areas other than the underarms; or
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
See also: Side effects (in more detail)
What other drugs will affect Botox?
Other medicines can increase certain side effects of Botox, especially: cold or allergy medicine, muscle relaxers, sleeping pills, bronchodilators, bladder or urinary medicines, and irritable bowel medicines. Tell your doctor about all your current medicines.
Other drugs may interact with Botox, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.
Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
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More about onabotulinumtoxinA
- OnabotulinumtoxinA Side Effects
- During Pregnancy
- Dosage Information
- Drug Interactions
- Support Group
- En Español
- 249 Reviews
- Drug class: skeletal muscle relaxants
- OnabotulinumtoxinA Cosmetic Injection
- OnabotulinumtoxinA Injection
- Onabotulinumtoxina Intramuscular (Advanced Reading)