In clinical trials, 30.6% of patients (33/108) who were not using clean intermittent catheterization (CIC) prior to injection, required catheterization for urinary retention following treatment with BOTOX® 200 Units as compared to 6.7% of patients (7/104) treated with placebo. The median duration of postinjection catheterization for these patients treated with BOTOX® 200 Units (n = 33) was 289 days (minimum 1 day to maximum 530 days) as compared to a median duration of 358 days (minimum 2 days to maximum 379 days) for patients receiving placebo (n = 7).
The incidence of UTI increased in patients who experienced a maximum post-void residual (PVR) urine volume ≥200 mL following BOTOX injection compared to those with a maximum PVR <200 mL following BOTOX injection, 44% versus 23%, respectively. No change was observed in the overall safety profile with repeat dosing during an open-label, uncontrolled extension trial.
In fertility studies of BOTOX (4, 8, or 16 Units/kg) in which either male or female rats were injected intramuscularly prior to mating and on the day of mating (3 doses, 2 weeks apart for males, 2 doses, 2 weeks apart for females) to untreated animals, reduced fertility was observed in males at the intermediate and high doses and in females at the high dose. The no -effect doses for reproductive toxicity (4 Units/kg in males, 8 Units/kg in females) are approximately equal to the maximum recommended human dose of 400 Units on a body weight basis (Units/kg).
According to the PREEMPT paradigm, one injection of 5 units of onabotulinumtoxinA into four sites (total 20 units) into the frontalis muscle is done. The injection points are located by visually drawing a line up from the medial edge of the supraorbital rim. Patients will be injected into the muscle in the upper third of the forehead at least 1 to 2 fingerbreadths above the corrugator injection site. The lateral muscle injection areas are parallel and approximately 1 fingerbreadth lateral to the medial injection site, which is roughly in line with either the midpupillary line or the lateral edge of the cornea, which is the limbus line. In cases in which I am worried about ptosis, I inject the frontalis close to the hairline. In order to reduce the risk of these unwanted effects, injections should be administered in the upper third of the forehead only. The needle should be inserted at a 45° angle superiorly. Because the frontalis is an elevator muscle, weakening can cause brow ptosis or exacerbate preexisting brow ptosis.

The primary release procedure for BOTOX uses a cell-based potency assay to determine the potency relative to a reference standard. The assay is specific to Allergan's products BOTOX and BOTOX Cosmetic. One Unit of BOTOX corresponds to the calculated median intraperitoneal lethal dose (LD50) in mice. Due to specific details of this assay such as the vehicle, dilution scheme, and laboratory protocols, Units of biological activity of BOTOX cannot be compared to nor converted into Units of any other botulinum toxin or any toxin assessed with any other specific assay method. The specific activity of BOTOX is approximately 20 Units/nanogram of neurotoxin protein complex.
The only difference between the two procedures is that with Botox for migraines, they may do a few more shots in areas where the pain is experienced. Personally, I usually get between 30 and 40 shots, concentrated mostly on the right side of my head where the pain occurs, at the base of my skull, and on my neck and shoulders, where I tend to hold tension, as doing so can cause a migraine. Botox for migraines can have the same aesthetic effect that cosmetic Botox has, which kills two birds with one stone for people who may desire that effect. "We do it along wrinkle lines and keep it symmetrical," says Ravitz, which explains the erasing of lines and temporary plumping of wrinkles.

There has not been a confirmed serious case of spread of toxin effect away from the injection site when BOTOX® has been used at the recommended dose to treat chronic migraine, severe underarm sweating, blepharospasm, strabismus, or when BOTOX® Cosmetic has been used at the recommended dose to treat frown lines, crow’s feet lines, and/or forehead lines.
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