The Impact of Age on Botulinum Toxin Potency in Facial Rhytides Treatment

Botulinum toxin is approved by the FDA for the treatment of facial wrinkles. Patients are usually older than 45 years and their main demand is to treat pre-existing facial wrinkles. However with the increasing popularity of this technique, younger patients, aged 25 to 35 years, are now seeking botulinum toxin injection as a preventive measure for rhytides. The usual dose used for the treatment of facial rhytides in a female patient older than 45 years is 50 units. No consensus exists concerning the dose of botulinum toxin that should be used in younger patients. Hypothesis: lower dose of botulinum toxin is sufficient to give good and long lasting results in young patients. The objective of this randomized open-label study is to evaluate the effect of lower doses of Botulinum toxin on the facial rythides in young patients.

Botulinum toxin is approved by the FDA for the treatment of facial wrinkles. Patients are usually older than 45 years and their main demand is to treat pre-existing facial wrinkles. However with the increasing popularity of this technique, younger patients, aged 25 to 35 years, are now seeking botulinum toxin injection as a preventive measure for rhytides. The usual dose used for the treatment of facial rhytides in a female patient older than 45 years is 50 units. No consensus exists concerning the dose of botulinum toxin that should be used in younger patients. Hypothesis: lower dose of botulinum toxin is sufficient to give good and long lasting results in young patients.

The objective of this randomized open-label study is to evaluate the effect of lower doses of Botulinum toxin on the facial rythides in young patients.

In this trial, patients will be divided into 3 groups: Group 1 patients will be 25-35 years old and will be injected with 30 units of botulinum toxin into the upper face, group 2 patients will be older than 45 and will be injected with the same amount of botulinum toxin into the upper face and group 3 patients will be older than 45 and will be treated with the usual 50 units dose (control group). Patients older than 45 will be randomized between groups 2 and 3. Validated photonumeric scales will be used to evaluate the wrinkles at rest and with muscle contraction at 2, 4, 8, 12, 16, 20, 24 weeks post injection in the 3 groups. The patient satisfaction rate and the Physician global assessment will also be evaluated in the 3 groups. The scores will be determined by 3 independent blinded raters.

Hypothesis:

(1) the low dose will be sufficient to treat the group 1 patients and it will be insufficient to treat the group 2 patients. (2) The results will last longer in groups 1 and 3 patients compared to group 2 patients. (3) Group 1 patients treated with low doses of botulinum toxin will have similar results to the group 3 patients treated with the standard dose of botulinum toxin.

Eligibility Criteria:
Inclusion Criteria:

* female patients presenting to our clinic for Facial wrinkle treatment with botulinum toxin
* Must be between 25-35 years old to be included in group 1.
* Must be older than 45 to be included in groups 2 and 3.

Exclusion Criteria:

* Patients with previous periorbital/forehead surgery
* Patients who plucked the upper eyebrow margin
* Patients with eyebrow tatoos
* Patients with upper face botulinum toxin injection in the past 12 months
* Patients with resorbable upper face fillers injection in the past 12 months
* Patients with previous permanent upper face fillers injection
* Pregnant patients
* Lactating patients
* Patients with preexisting neuromuscular conditions (myasthenia gravis, Eaton Lambert syndrome)
* Patients using medication that could potentiate the effect of botulinum (ex: aminoglycoside antibiotics)
* Patients with sensitivity to botulinum toxin or human albumin