Of course, Claritin does nothing to help a stuffy nose. It's the wrong class of medicine. True pseudoephedrine (from behind the counter) is the go to for increasing drainage. The new stuff (OTC with phenylephrine) only works as well as a placebo.
That's going to depend on the person, at least as a nasal spray, for me at least it has a noticeable effect that I'm certain isn't placebo. Back when I took it, systemic oral pseudoephedrine (Sudafed) was noticeably better (stopped that route due to it exacerbating my anxiety).
Fortunately, there are nasal steroid sprays, and 2 of them are now OTC, and you can get a prescription for the azelastine antihistamine nasal spray (Astelin, Astepro), the latter ought to pose little risk to your brain. A combination of the two, with occasional very short courses of nasal spray phenylephrine (4 hour) or oxymetazoline (12 hour) curbed my rate of getting sinus infections from more than 1 a year to one every few years.
Fortunately, it's still easy to get in the UK, and doesn't exacerbate my anxiety.
I never tried that, in fact I'm pretty sure I stuck to the 30 mg immediate dosing version, which was useful but not quite a "miracle drug", then again I'm sure our sinuses are quite different. So I haven't really missed it, between the effect on anxiety, and much later living in a notorious area for meth, where my usual pharmacy is in a city where even dispensing of OTC versions requires a doctor's prescription.
If my doctors really wants to clear my sinuses while treating for an infection, they use a Medrol DosePak (serious steroid with a lot up front and then it quickly tapers), something my father is all to familiar with due to his poison ivy allergy and ability to get into the stuff.
It's two of the 60mg "Sudafed Decongestant" (UK Branding) tablets, which I don't believe are sustained release (typical/listed dose is 60mg - I confirmed with my GP that 120mg is fine FOR ME [do NOT take this as general advice] if taken infrequently). I generally only need a single dose during the day for my sinuses to stay clear enough to be manageable (and sinus infections are infrequent anyway), so the large upfront dose works for me and is well under the daily recommended maximum (240mg).
Loratadine and Benadryl are antihistamines, pseudoephedrine is a stimulant that has a decongestant affect.
There's Claritin branded combo pills that have Loratadine and a decongestant, but "Claritin" in normal conversation should probably be reserved for the one active ingredient Loratadine pills.
Back in the eighties in Seattle I would take a Benadryl every morning, because I was allergic to just about everything (I was poke tested). Eventually I downgraded to chlor-trimaton. So I guess I'm potentially doomed.
Here in Denver I rarely have allergy issues.
My mention of doom is because I got the impression that the rise in risk (10%) was associated pretty hard with long term use, which I had, and distant past wasn't mentioned as a mitigation.
Maybe try the other 2nd generation drugs next time you feel the need (Allegra is yet another compound)?