Botox (OnabotulinumtoxinA): Uses, Dosage and Side Effects in Canada

Botox is a brand name for onabotulinumtoxinA, a purified form of botulinum toxin type A. It is injected into specific muscles or tissues and its effect is temporary. Two products are authorized in Canada, both from AbbVie: Botox, for medical conditions, and Botox Cosmetic, for facial lines and neck bands.

Both are prescription drugs. Botox must be given by a physician who is qualified and experienced in its use. For chronic migraine, and for Botox Cosmetic, another authorized prescriber with the same qualifications and experience may give it. It is not a medicine you pick up at a pharmacy and take at home.

Avee Health does not provide Botox, and a phone visit cannot replace an in-person injection. Your family doctor can tell you who to see for your condition. BC residents can speak with a BC-licensed doctor by phone through Avee Health about their symptoms and next steps.

In Canada, Botox is authorized for:

• Blepharospasm (uncontrolled eyelid spasm) and strabismus (misaligned eyes), in people 12 and older
• Cervical dystonia (neck muscle spasm) in adults
• Focal spasticity (muscle stiffness) in adults, and spasticity of the arm or leg in children 2 and older
• Primary hyperhidrosis of the armpits (heavy sweating), in people 18 and older
• Chronic migraine in adults who have headaches on at least 15 days a month, lasting 4 hours or more
• Overactive bladder, and bladder overactivity caused by a nerve condition, in adults who did not get enough benefit from anticholinergic medicines or could not tolerate them

Botox Cosmetic is authorized for adults for:

• Upper facial lines: forehead lines, crow's feet and frown lines between the eyebrows
• Platysma bands (vertical neck bands)

Botox Cosmetic is not authorized for anyone under 18.

Botulinum toxin type A blocks the signal between nerves and the muscles or glands they control. The injected muscle relaxes. Depending on where it is injected, this can ease spasms, soften lines caused by muscle movement, reduce sweating or calm an overactive bladder.

The effect wears off, so treatment is repeated. Botox units are specific to this product. They cannot be converted into the units of another botulinum toxin product.

Your doctor sets your dose. Botox is not taken at home. The number of units and the injection sites depend on the condition, the muscles treated and how you respond.

How soon it works and how long it lasts:

• Eyelid spasm: the effect starts within about 3 days, peaks at 1 to 2 weeks and lasts about 3 months
• Strabismus: the injected muscle weakens within 1 to 2 days. The effect lasts 2 to 6 weeks and wears off over a similar time
• Cervical dystonia: improvement usually begins within 2 weeks and is greatest at about 6 weeks
• Spasticity: in adults treated in the arm, muscle tone improved within 2 weeks, with the strongest effect at 4 to 6 weeks. In children, improvement can be expected within 7 days
• Heavy armpit sweating: the effect lasts 4 to 7 months, 5.2 months on average
• Bladder conditions: improvement within about 2 weeks. In trials the effect lasted a median of about 24 weeks for overactive bladder and 36 to 42 weeks for bladder overactivity caused by a nerve condition
• Upper facial lines and neck bands (Botox Cosmetic): the effect lasts about 4 months

Treatments must be spaced out:

• Botox Cosmetic: no more often than every 3 months
• Eyelid spasm: repeated when the effect wears off, usually after about 3 months
• Cervical dystonia: no more often than every 2 months
• Spasticity: at least 12 weeks between treatments
• Chronic migraine: every 12 weeks
• Bladder conditions: at least 3 months between treatments
• Strabismus and armpit sweating: repeated only after the effect of the last treatment has worn off