Other side effects of BOTOX® and BOTOX® Cosmetic include: dry mouth, discomfort or pain at injection site, tiredness, headache, neck pain, eye problems: double vision, blurred vision, decreased eyesight, drooping eyelids, swelling of eyelids, dry eyes, and drooping eyebrows. In people being treated for urinary incontinence other side effects include: urinary tract infection, painful urination, and/or inability to empty your bladder on your own. If you have difficulty fully emptying your bladder after receiving BOTOX®, you may need to use disposable self-catheters to empty your bladder up to a few times each day until your bladder is able to start emptying again.

The most common side effects of Botox injections are neck pain and stiffness at the injection site. You may develop a headache afterward. You may also experience temporary muscle weakness in your neck and upper shoulders. This can make it hard to keep your head upright. When these side effects occur, they usually resolve on their own within a few days.
When I wean patients off of treatment, I do not change the dose but rather delay the treatment cycle to 16 weeks and monitor headaches in the last 4 weeks. If the patient remains well-controlled, I increase the treatment window to 20 weeks, and so on. I use this method to establish the level at which patients need reinjection to prevent breakthrough headaches.11-13
The ideal needle to use is a 30G or 31G, half-inch needle. Longer needles are problematic as they encourage deeper injections, which can increase the risk of muscle weakness, and most of the side effects such as neck pain stem from muscle weakness. Perseverative-free normal saline is the only diluent that should be used. There is a case study of a patient who died when onabotulinumtoxinA was mixed with a local anesthetic agent. The pivotal trial established an effective dose using 2 mL/100 units of onabotulinumtoxinA. A fact that is often overlooked is that the mean dose in the trial was 165 units. The patients all received 155 units with a fixed dose, fixed-site injection protocol, and an option of an additional 40 units to follow the pain. This resulted in a mean dose of 165 units, which is the standard that should be used to achieve the efficacy results reviewed above.
“I don’t think it is physically addictive,” says Dr. Matarasso. “But, I have to be very frank with you, when I get a new patient I tell them (and I say this tongue-in-cheek) this product is truly addictive. I make jokes with my patients that we need a 12-step program for it, because when it’s done correctly, it’s a very simple office procedure, with impressive cosmetic results.”
Why Botox works isn’t completely clear. There’s some evidence that it may reduce the production of neurotransmitters related to pain in the areas where it’s injected. There’s also some evidence that it may have a broader effect on the brain’s pain centers, reducing the sensitivity that causes migraine sufferers to react to migraine triggers. While the exact mechanisms are poorly understood, the studies, as well as many of my patients’ experiences, do show a real benefit for many people.
Ray Chester, an attorney in Austin who has represented several plaintiffs in lawsuits against Allergan, says that just about all the cases he has handled involved off-label use of the drug. In 2014 a New York couple argued that Botox, which they chose to try off-label to treat their son's cerebral-palsy symptoms, caused life-threatening complications. The family was awarded $6.75 million by a jury. Allergan, which initially planned to appeal, ended up privately settling the case with the family, and the terms of the settlement have been kept confidential.
BOTOX is indicated for the treatment of upper limb spasticity in adult patients, to decrease the severity of increased muscle tone in elbow flexors (biceps), wrist flexors (flexor carpi radialis and flexor carpi ulnaris) , finger flexors (flexor digitorum profundus and flexor digitorum sublimis), and thumb flexors (adductor pollicis and flexor pollicis longus).

Still, Botox's use for depression raises a question that confounds some researchers. In some cases, how Botox works is evident: the toxin can block the signals between nerves and muscles, which is why it can help calm an overactive bladder, say, or a twitching eye, or the facial muscles that make wrinkles more apparent. In other cases, however (with migraines as well as with depression), scientists are flummoxed. They may have noticed that the drug works for a given condition, but they aren't always sure why--in sciencespeak, they don't know what the mechanism is.
I had a consult and the doctor quickly realized that I was a candidate for Botox. He ordered an MRI and doppler of my brain to make sure everything else was A-OK, and then the rest was just waiting on my insurance company. With Botox (I’m not sure if it’s all Botox or just prescription), the insurance company orders it from a pharmacy and sends it to the doctor.
I tell my patients that it is not the total price that is important, but how many units are used. For instance, if a patient goes to a spa and pays $150 per area, that may sound like a great deal. However, when the patient ask how long the treatment is supposed to last, the spa responds "2 months". I have seen that many of those less expensive treatments often consist of around 10 units (and therefore carrying a "non-deal" $15 cost per unit!). So, what initially looks like a great bargain, is in fact just a treatment with an inadequate amount of Botox. Always ask your injector how many units they are using, so you can determine what price/unit you are getting. Experienced injectors know that there is no such thing as a standard amount of units, as everyone's facial anatomy and muscular strengths are variable, even from one side of the face to the other.
It is not known whether BOTOX® is safe or effective to treat increased stiffness in upper limb muscles other than those in the elbow, wrist, fingers, and thumb, or in lower limb muscles other than those in the ankle and toes. BOTOX® has not been shown to help people perform task-specific functions with their upper limbs or increase movement in joints that are permanently fixed in position by stiff muscles. Treatment with BOTOX® is not meant to replace existing physical therapy or other rehabilitation that may have been prescribed.