Howdy folks,
Try not to get too caught up in all the 'drugs are REALLY bad' hype. If it's in the rules, stick to them, but if your doc says that one sudafed may make you dizzy (in a healthy individual), or some such dibble, don't take his/her word quite as gospel.
To help solidify my point, consider me... stands and waves for all to see
To aid my bodybuilding endeavours, I sometimes take a mixture of over-the-counter (OTC) drugs to aid in thermogenisis. The stack I usually use (which I started after thorough study) consists of 2 Sudafed, 2 No-Doz (total 200mg caffeine), and one Aspirin. After a couple of days I realised that I could function perfectly normally (although I had to go the bathroom every 20 mintues...), and so if I had to fly then I didn't think twice about being on this stack of drugs. If anything it helped, as I was totally wired ALL DAY (but don't abuse this combination for this purpose), and felt no effects of fatigue.
My sinuses also remained completely unblocked for the entire time.
My point is that while your doctors rant and rave about how this might happen, or that might happen, or how your head may explode when passing through the transition layer with a dose of Sudafed in you, providing you're otherwise (even half) healthy, you shouldn't have anything to worry about.
(Disclaimer - I'm not advocating the use of the drug stack above, if you want to learn more just ask, if you take it and die, well, I guess I told you so... )
While I'm writing, I've found the best thing (in Australia) is a product called 'Spray-tish'. A couple of sprays in the nose has it cleared better than if it was perfectly normal. Not sure if it's still available as I haven't bought any for about 2 years.
That's all, I'm off to bed.
Cheers,
Turbofan