Botox (OnabotulinumtoxinA) - Intramuscular, Intradetrusor, or Intradermal


Botox carries a black box warning for the distant spread of toxin effects. The effects of onabotulinumtoxinA and all botulinum toxin products may spread from the area of injection to produce symptoms in unwanted areas of the body. These symptoms can include decreased muscle strength, generalized muscle weakness, double vision, drooping upper eyelid, difficulty swallowing, hoarseness, slurred speech, loss of bladder control, and breathing difficulties. These symptoms have been reported hours to weeks after injection. Trouble swallowing and breathing can be life-threatening, and there have been reports of death. The risk of symptoms is probably greatest in children treated for spasticity (a condition in which muscles stiffen or tighten, preventing normal movement or function), but symptoms can also occur in adults, particularly in those who have an underlying condition that would predispose them to these symptoms.

What Is Botox?

Botox (onabotulinumtoxinA) is a prescription injection with various medical uses. It is injected into certain areas of the body by a healthcare provider to treat the following conditions:

Botox helps to treat most of these conditions because it can block the nerve signals when it is injected into specific muscles of the body (neuromuscular blocking agent). It also inhibits the release of acetylcholine, a type of chemical messenger or neurotransmitter. This prevents muscle contraction which leads to muscle paralysis.

Drug Facts

Generic Name: OnabotulinumtoxinA

Brand Name(s): Botox

Drug Availability: Prescription

Therapeutic Classification: Neuromuscular blocking agent and acetylcholine release inhibitor

Available Generically: No

Controlled Substance: N/A

Administration Route: Intramuscular (into the muscle), Intradetrusor (into the bladder), or Intradermal (into the skin)

Active Ingredient: Botulinum Toxin Type A

Dosage Form(s): Injection

What Is Botox Used For?

Botox is used to treat the following conditions:

How to Take Botox

Your healthcare provider will prescribe your exact dose of Botox and tell you how often it should be given. A few things to keep in mind while taking Botox:

  • A healthcare provider gives this medicine as a shot under your skin or into a muscle.
  • You may be given medicine to numb the injection site.
  • If you receive Botox around your eyes, you may be given eye drops or ointment to numb the area. After your injection, you may need to wear a protective contact lens or an eye patch.
  • If you are being treated for bladder problems, you may also receive medicine to help prevent urinary tract infections before, during, or after treatment with Botox.
  • If you are being treated for excessive sweating, shave your underarms but do not use deodorant for 24 hours before your injection. Avoid exercise, hot foods or liquids, or anything else that could make you sweat for 30 minutes before your injection.
  • The recommended treatment schedule for chronic migraine is every 12 weeks.
  • Botox starts working slowly. Once your condition has improved, the medicine will last about three months. Then, the effects will slowly go away. You might need more injections to treat your condition.


Botox is normally stored, handled, and usually administered by your healthcare provider. Unopened vials of Botox are stored in a refrigerator for up to 36 months. Once Botox is reconstituted for injection, it should be stored in a refrigerator and used within 24 hours. Reconstituted Botox should be clear, colorless, and free of particulate matter.

Off-Label Uses

Healthcare providers may prescribe Botox for off-label uses, meaning for conditions not specifically indicated by the Food and Drug Administration (FDA). 

Off-label uses of Botox include:

How Long Does Botox Take to Work?

Botox starts to work slowly, and the time it takes Botox to work may be different for everyone. Generally:

  • Muscle spasms in the eyelids should improve within three to 10 days.
  • Eye muscle problems should improve one or two days after the injection, lasting for two to six weeks.
  • Neck pain should improve within two to six weeks.
  • Arm stiffness should improve within four to six weeks.

What Are the Side Effects of Botox?

This is not a complete list of side effects, and others may occur. A healthcare provider can advise you on side effects. If you experience other effects, contact your pharmacist or a healthcare provider. You may report side effects to the FDA at or 800-FDA-1088.

Common Side Effects

The common side effects of Botox may vary depending on which condition your healthcare provider is treating and where they inject the medication. The common side effects of Botox include:

  • Injection site pain
  • Sweating
  • Backache
  • Neck pain
  • Pain in limb
  • Headache
  • Dry eyes
  • Drooping eyelid(s)
  • Inability to empty all the urine from your bladder (urinary retention)
  • Urinary tract infections
  • Cough
  • Rhinitis (nose membrane inflammation due to a virus)
  • Upper respiratory infection
  • Fever 
  • Flu-like symptoms

Severe Side Effects

Call your healthcare provider right away if you have serious side effects. Call 911 if your symptoms feel life-threatening or if you think you have a medical emergency. Serious side effects and their symptoms can include the following:

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness or trouble breathing
  • Blurred or double vision, droopy eyelids, increased pressure behind the eyes
  • Change in how much or how often you urinate, trouble urinating, painful urination, bloody or cloudy urine, lower back or side pain
  • Changes in speech
  • Chest pain, slow or uneven heartbeat
  • Fever, chills, cough, stuffy or runny nose, sore throat, body aches
  • Headache, increased sweating, warmth or redness in your face, neck, or arm
  • Muscle weakness
  • Seizures
  • Trouble swallowing, talking, or breathing
  • Death

Long-Term Side Effects

Long-term effects of Botox are lacking.

Report Side Effects

Botox may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your healthcare provider may send a report to the FDA's MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

Dosage: How Much Botox Should I Take?

Your healthcare provider will determine and administer the proper dosage of Botox for you.


The following modifications (changes) should be kept in mind when using Botox:

Pregnancy or breastfeeding: There's not enough scientific evidence available to tell whether there would be a risk to your fetus when used during pregnancy or to your child during breastfeeding. If you're pregnant or breastfeeding, please talk with your healthcare provider before starting Botox.

Adults over 65: Based on the clinical studies of Botox, no overall differences in safety or effectiveness were found between adults over 65 and adults less than 65. However, some adults over 65 may be more sensitive to Botox than others.

Children: It is not known whether Botox is safe and effective in people younger than:

Missed Dose

If you miss your appointment to receive your Botox injection please call your healthcare provider for further instructions.

Overdose: What Happens If I Take Too Much Botox?

The symptoms of a suspected overdose of Botox include progressive weakness and paralysis that may lead to trouble breathing (respiratory failure). Symptoms of overdose are likely not to be present immediately following injection. Signs of systemic weakness and muscle paralysis may occur within a day of a large exposure or up to several weeks after a smaller exposure.

If you think you're experiencing an overdose or life-threatening symptoms, seek immediate medical attention.

What Happens If I Overdose on Botox?

If you think you or someone else may have overdosed on Botox, call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses or isn't breathing after taking Botox, call 911 immediately.


Drug Content Provided by IBM Micromedex®

It is very important that your doctor check your or your child's progress at regular visits. This will allow your doctor to see if the medicine is working properly and to decide if you should continue to receive it. Blood and urine tests may be needed to check for unwanted effects.

Serious muscle reactions have occurred within hours to weeks after receiving this medicine. If you start to have muscle weakness, loss of bladder control, or trouble with swallowing, talking, or breathing, call your doctor right away. In some patients, these problems could be life-threatening and may require an immediate treatment in a hospital or clinic.

This medicine may make your muscles weak and cause vision problems (eg, bleeding inside the eye). Do not drive or do anything else that could be dangerous until you know how this medicine affects you.

This medicine may reduce blinking of the eye which can lead to an increased risk of eye problems (eg, corneal exposure and ulcers). Tell your doctor right away if you have a reduced blinking of the eye.

This medicine may cause serious allergic reactions, including anaphylaxis, which can be life-threatening and requires immediate medical attention. Call your doctor right away if you have a rash, itching, hoarseness, trouble breathing, trouble swallowing, or any swelling of your hands, face, or mouth while you are receiving this medicine.

After you have received this medicine and your vision or muscle spasms are better, you may find that you are a lot more active than you were before. You should slowly increase your activities to allow time for your body to get stronger. Also, before you start an exercise program, check with your doctor.

This medicine may increase your chances of having bronchitis or upper respiratory tract infections when given for upper limb spasticity. Tell your doctor right away if you have trouble breathing, sneezing, sore throat, coughing, or a fever.

This medicine may cause a condition called autonomic dysreflexia in patients with nervous system disorders (eg, spinal cord injury). It can be a life-threatening condition and requires immediate medical attention. Call your doctor right away if you have headache, increased sweating, slow heartbeat, warmth or redness in your face, neck, or arm, or have problems in urinating while using this medicine.

This medicine is made from donated human blood. Some human blood products have transmitted viruses to people who have received them, although the risk is low. Human donors and donated blood are both tested for viruses to keep the transmission risk low. Talk with your doctor about this risk if you are concerned.

Check with your doctor right away if you have difficulty urinating or a burning sensation while urinating after receiving this medicine.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

What Are Reasons I Shouldn’t Take Botox?

You should not take Botox if you have one of the following:

  • If you're allergic to any botulinum toxin product or any of the components in the formulation. Ask your pharmacist or healthcare provider for a complete list of the ingredients if you're unsure.
  • Present infection at the proposed injection site(s).
  • For intradetrusor (bladder) injection: Current urinary tract infection or urinary retention or post-void residual (PVR) urine volume >200 milliliters (mL) and not routinely performing clean intermittent self-catheterization (CIC), a method of draining urine via a catheter inserted into the urethra, past the sphincter into the bladder.

Please let your healthcare provider know if you have breathing or lung problems, bleeding problems, heart or blood vessel disease, or nerve or muscle problems (including Lou Gehrig disease, Lambert-Eaton syndrome, or myasthenia gravis) because taking Botox may worsen your condition. Also, tell your healthcare provider if you have ever had face surgery or have a urinary tract infection, trouble urinating, diabetes, or multiple sclerosis.

What Other Medications Interact With Botox?

Use caution when taking Botox with the following medications:

  • Aminoglycosides such as amikacin, Gentak (gentamicin), streptomycin, Tobrex (tobramycin), and other drugs that interfere with neuromuscular transmission
  • Anticholinergic drugs
  • Muscle relaxers
  • Other botulinum neurotoxin products

This is not a complete list of medicines that interact with Botox.

For more detailed information about medication interactions with Botox, speak with your pharmacist or other healthcare provider. 

Be sure to talk with your healthcare provider about any other medicines you take or plan to take, including over-the-counter (OTC), nonprescription products, vitamins, herbs, or plant-based medicines.

What Medications Are Similar?

Botox is a Botulinum toxin Type A. Dysport and Xeomin are Type A Botulinum toxin injections like Botox.

Frequently Asked Questions

  • How do I take Botox?

    Botox is given by a healthcare provider as a shot under your skin or into a muscle, depending on the condition your healthcare provider is treating.

  • What is the black box warning for Botox?

    Botox carries a black box warning for distant spread of toxin effects. The effects of onabotulinumtoxinA and all botulinum toxin products may spread from the area of injection to produce symptoms in unwanted areas of the body. These symptoms can include decreased muscle strength, generalized muscle weakness, double vision, drooping upper eyelid, difficulty swallowing, hoarseness, slurred speech, loss of bladder control, and breathing difficulties.

  • How does Botox work?

    Botox works by blocking the nerve signals when it is injected into certain muscles of the body (neuromuscular blocking agent) and it is inhibits the release of acetylcholine, a type of chemical messenger, or neurotransmitter, which prevents muscle contraction leading to muscle paralysis.

  • Are the effects of Botox permanent?

    No, the effects of Botox wear off over time. Once your condition has improved, the medicine will last about three months; the effects will slowly disappear. After that, you might need more injections to treat your condition.

How Can I Stay Healthy While Taking Botox?

Below are some general tips to support your health while taking Botox:

  • Botox may cause loss of strength, muscle weakness, blurred vision, dizziness, or drooping eyelids. Do not drive or do anything else that could be dangerous until you know how Botox affects you.
  • Your healthcare provider will schedule follow-up appointments to check on the effects of Botox.
  • Keep all appointments and follow up with your healthcare provider to ensure successful treatment.

Medical Disclaimer

Verywell Health's drug information is meant for educational purposes only and is not intended as a replacement for medical advice, diagnosis, or treatment from a healthcare provider. Consult your healthcare provider before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

37 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Food and Drug Administration. Botox label.

  2. Crafts TD, Lyo V, Rajdev P, Wood SG. Treatment of achalasia in the bariatric surgery population: a systematic review and single-institution experienceSurg Endosc. 2021;35(9):5203-5216. doi:10.1007/s00464-020-08015-3

  3. De Robles MS, Young CJ. Real world outcomes of lateral internal sphincterotomy vs botulinum toxin for the management of chronic anal fissuresAsian J Surg. 2022;45(1):184-188. doi:10.1016/j.asjsur.2021.04.027

  4. Marchese MR, Bussu F, Settimi S, Scarano E, Almadori G, Galli J. Not only gustatory sweating and flushing: signs and symptoms associated to the Frey syndrome and the role of botulinum toxin A therapyHead Neck. 2021;43(3):949-955. doi:10.1002/hed.26561

  5. Foster L, Clapp L, Erickson M, Jabbari B. Botulinum toxin A and chronic low back pain: a randomized, double-blind study. Neurology. 2001;56(10):1290-1293. doi:10.1212/wnl.56.10.1290

  6. Chancellor MB, Smith CP. Use of botulinum toxin in the genitourinary systemHandb Exp Pharmacol. 2021;263:171-184. doi:10.1007/164_2019_308

  7. Freund BJ, Schwartz M. Treatment of whiplash associated neck pain [corrected] with botulinum toxin-A: a pilot study. J Rheumatol. 2000;27(2):481-484. Erratum in: J Rheumatol. 2000;27(6):1577.

  8. Bowen DK, Meyer T, Rosoklija I, et al. Botulinum toxin in patients at-risk for bladder augmentation: durable impact or kicking the can? Neurourol Urodyn. 2022;41(6):1406-1413. doi:10.1002/nau.24962

  9. Benyamini L, Gil Z, Cohen JT. Management of aphonic patients following total laryngectomy and trachea esophageal punctureIsr Med Assoc J. 2014;16(12):768-770.

  10. Alberty J, Oelerich M, Ludwig K, Hartmann S, Stoll W. Efficacy of botulinum toxin A for treatment of upper esophageal sphincter dysfunction. Laryngoscope. 2000;110(7):1151-1156. doi:10.1097/00005537-200007000-00016

  11. Porta M, Gamba M, Bertacchi G, Vaj P. Treatment of sialorrhoea with ultrasound guided botulinum toxin type A injection in patients with neurological disorders. J Neurol Neurosurg Psychiatry. 2001;70(4):538-540. doi:10.1136/jnnp.70.4.538

  12. Grüner S, Schulz A, Schlüter-Brust K, Lippert-Grüner M. Botulinum toxin for chronic lateral epicondylitis (LE). Botulinumtoxin bei chronischer Epicondylitis humeroradialisZ Orthop Unfall. 2021;159(5):554-564. doi:10.1055/a-1202-6220

  13. Brin MF, Lyons KE, Doucette J, et al. A randomized, double masked, controlled trial of botulinum toxin type A in essential hand tremor. Neurology. 2001;56(11):1523-1528. doi:10.1212/wnl.56.11.1523

  14. Lagalla G, Millevolte M, Capecci M, Provinciali L, Ceravolo MG. Botulinum toxin type A for drooling in Parkinson's disease: a double-blind, randomized, placebo-controlled study. Mov Disord. 2006;21(5):704-707. doi:10.1002/mds.20793

  15. Whittaker KW, Matthews BN, Fitt AW, Sandramouli S. The use of botulinum toxin A in the treatment of functional epiphora. Orbit. 2003;22(3):193-198. doi:10.1076/orbi.

  16. Pandey S, Srivanitchapoom P, Kirubakaran R, Berman BD. Botulinum toxin for motor and phonic tics in Tourette's syndromeCochrane Database Syst Rev. 2018;1(1):CD012285. doi:10.1002/14651858.CD012285.pub2

  17. Pan Y, Li J, Zhang J, Wang X, Jia Y. Thyroarytenoid botulinum toxin injection for refractory laryngeal contact granulomaAm J Otolaryngol. 2022;43(4):103482. doi:10.1016/j.amjoto.2022.103482

  18. Leplow B, Pohl J, Wöllner J, Weise D. Individual response to botulinum toxin therapy in movement disorders: a time series analysis approachToxins (Basel). 2022;14(8):508. doi:10.3390/toxins14080508

  19. Jabbari B, Machado D. Treatment of refractory pain with botulinum toxins--an evidence-based reviewPain Med. 2011;12(11):1594-1606. doi:10.1111/j.1526-4637.2011.01245.x

  20. Yoshida K. Effects of botulinum toxin type A on pain among trigeminal neuralgia, myofascial temporomandibular disorders, and oromandibular dystoniaToxins (Basel). 2021;13(9):605. doi:10.3390/toxins13090605

  21. Koudsie S, Coste-Verdier V, Paya C, et al. Évaluation a long terme de l’éfficacité de la toxine botulique dans l’ésotropie precoce [Long term outcomes of botulinum toxin injections in infantile esotropia]J Fr Ophtalmol. 2021;44(4):509-518. doi:10.1016/j.jfo.2020.07.023

  22. Talebnejad MR, Sharifi M, Nowroozzadeh MH. The role of botulinum toxin in management of acute traumatic third-nerve palsy. J AAPOS. 2008;12(5):510-513. doi:10.1016/j.jaapos.2008.03.009

  23. Sinclair CF, Gurey LE, Blitzer A. Oromandibular dystonia: long-term management with botulinum toxinLaryngoscope. 2013;123(12):3078-3083. doi:10.1002/lary.23265

  24. Kaye R, Blitzer A. Chemodenervation of the larynx. Toxins (Basel). 2017;9(11):356. doi:10.3390/toxins9110356

  25. Scuteri D, Tonin P, Nicotera P, et al. Pooled analysis of real-world evidence supports anti-CGRP mAbs and onabotulinumtoxinA combined trial in chronic migraineToxins (Basel). 2022;14(8):529. doi:10.3390/toxins14080529

  26. Gurey LE, Sinclair CF, Blitzer A. A new paradigm for the management of essential vocal tremor with botulinum toxinLaryngoscope. 2013;123(10):2497-2501. doi:10.1002/lary.24073

  27. Zhang Y, Wang ZN, He L, et al. Botulinum toxin type-A injection to treat patients with intractable anismus unresponsive to simple biofeedback trainingWorld J Gastroenterol. 2014;20(35):12602-12607. doi:10.3748/wjg.v20.i35.12602

  28. Lightbody KA, Wilkie MD, Kinshuck AJ, et al. Injection of botulinum toxin for the treatment of post-laryngectomy pharyngoesophageal spasm-related disordersAnn R Coll Surg Engl. 2015;97(7):508-512. doi:10.1308/rcsann.2015.0011

  29. Rosow DE, Pechman A, Saint-Victor S, Lo K, Lundy DS, Casiano RR. Factors influencing botulinum toxin dose instability in spasmodic dysphonia patientsJ Voice. 2015;29(3):352-355. doi:10.1016/j.jvoice.2014.08.011

  30. Cabo-López I, García-Bermejo P, del Valle-Loarte M, García-Ruiz PJ. Toxina botulínica en el tartamudeo invalidante [Botulinum toxin in disabling stuttering]Rev Neurol. 2007;45(11):701.

  31. Clark GT, Ram S. Orofacial movement disordersOral Maxillofac Surg Clin North Am. 2016;28(3):397-407. doi:10.1016/j.coms.2016.03.003

  32. Oksanen E, Männistö V, Kormi E, Vallioniemi H, Suojanen J. Temporomandibular disorder patients benefit from intramuscular botulinum toxin type A InjectionsJ Craniofac Surg. 2022;33(4):1159-1161. doi:10.1097/SCS.0000000000008331

  33. Roland SB, Pripp AH, Msomphora MR, Kvarstein G. The efficacy of botulinum toxin A treatment for tension-type or cervicogenic headache: a systematic review and meta-analysis of randomized, placebo-controlled trialsScand J Pain. 2021;21(4):635-652. doi:10.1515/sjpain-2021-0038

  34. Donahue DM, Godoy IRB, Gupta R, Donahue JA, Torriani M. Sonographically guided botulinum toxin injections in patients with neurogenic thoracic outlet syndrome: correlation with surgical outcomesSkeletal Radiol. 2020;49(5):715-722. doi:10.1007/s00256-019-03331-9

  35. Carroll A, Barnes M, Comiskey C. A prospective randomized controlled study of the role of botulinum toxin in whiplash-associated disorderClin Rehabil. 2008;22(6):513-519. doi:10.1177/0269215507086778

  36. Ahsanuddin S, Roy S, Nasser W, Povolotskiy R, Paskhover B. Adverse events associated with botox as reported in a Food and Drug Administration database. Aesthetic Plast Surg. 2021;45(3):1201-1209. doi:10.1007/s00266-020-02027-z

  37. Scaglione F. Conversion ratio between Botox®, Dysport®, and Xeomin® in clinical practice. Toxins (Basel). 2016;8(3):65. doi:10.3390/toxins8030065