Phenylephrine is a selective ?1-adrenergic receptor agonist used primarily as a decongestant, as an agent to dilate the pupil, and to increase blood pressure. Phenylephrine has recently been marketed as a substitute for pseudoephedrine (e.g.,Sudafed (Original Formulation)), http://en.wikipedia.org/wiki/Phenylephrine I wonder if anyone has used this and it has helped. I have used this on a number of occassions when brain fog wont budge, but thought it was its stimulant effects helping but maybe more to do with increasing BP. I havent been officially diagnosed with OI but when brain fog is bad i struggle with worsening fog and fatigue when sitting and standing etc and i find lying down for 10-15mins helps and then i can go back to what i was doing for abit longer, i have also had bouts of sweat attacks also and wondering if it may just be OI?? After watching the utube in another post on pots/oi, im thinking its alot more common in cfs then most of us realise. The video did say if u normally have good or high blood pressure that this can be abit of a safety effect when someone has OI, where someone who normally has low BP will often collapse/more dizzy spells and struggle alot more then most. Also seems that low cortisol can play a part as well, i wonder if this is why pregnenolone has also helped me with brain fog as it can help increase cortisol levels thus BP. This is something that i havent really looked into but maybe why i still have bouts of brain fog/fatigue and adrenal fatigue still present shown in blood tests. Watching the utube on pots/oi was a light bulb moment for me, although it has been looking me in the face for years. Also maybe why tramadol helps me with brain fog as it can help maintain and or raise BP too. cheers!!