Brimonidine (Mirvaso) causes temporary constriction of blood vessels in the skin to reduce the appearance of facial redness and prominent blood vessels.
Brimonidine is a highly selective alpha-2 adrenergic receptor agonist. The millions of tiny blood vessels in the human face are lined with these alpha-2 receptors. When the gel is applied to the skin, the medication rapidly binds to these receptors, sending a strong signal to the smooth muscles in the blood vessel walls to constrict. This action forcibly clamps the dilated facial blood vessels shut. The clinical result is a visible, dramatic, and near-total reduction of facial redness that begins within 30 minutes of application, peaks at around 3 to 6 hours, and lasts for up to 12 hours.
Because the effect is temporary brimonidine is most often used strategically by patients who want to completely eliminate their redness for specific social events or job interviews.
However, a major limitation of brimonidine is that as the medication begins to wear off and the blood vessels open back up, many patients experience a phenomenon known as "rebound redness". This is where the facial flushing returns with a burning sensation sometimes appearing even more severe than the baseline redness before the gel was applied. Because of this side effect I find brimonidine to only be suitable for a small proportion of patients and it is not suitable as a daily treamtent.
