The Phenylephrine in 4-way is the obvious culprit and I'm really surprised
your Dr didn't know this.  Phenylephrine can cause the exact same symptoms
as overusing any stimulant, whether it is coffee or diet pills. 12 hr nose
spray isn't any better but the rebound happens a little quicker with
Phenylephrine. I used 4-way for many years in the past, but never at 4
bottles a week. That is a huge overdosage of Phenylephrine. You'll need to
taper off and this won't be easy. Measure and dilute each new bottle you
open by another 10% with saline water and always do the same amount of
squirts (1 or 2) and keep track of exactly how many times a day you use the
spray. Increase the dilution of each new bottle you open by another 10%
until you need to throw away a measured amount of a new bottle in order to
keep increasing dilution. Decrease the frequency of squirts used each day
and keep track so you can always be slowly decreasing frequency. After you
get down to using .05%  Phenylephrine or a twentyfold dilution and you are
using only 1 squirt at a time, then try stopping entirely or alternating
days. Then quit the Phenylephrine completely and don't buy any more. You may
need to use Sudafed  for a few weeks while tapering off the Phenylephrine as
the rebound will be severe. Also, start using a nasal steroid like Rhinacort
or Flonase regularly. If you really stick with it, you can taper yourself
off the Phenylephrine in 2-3 months.

Suggest you monitor your blood pressure closely while using the Sudafed and
see a good ENT to help you develop a better strategy for dealing with your
congestion.  Read the group FAQ and especially the section about saline
nasal irrigation. Regular saline irrigation would be very helpful in getting
your nose readjusted to life without Phenylephrine.

good luck,    AW

ps-oral Phenylephrine tablets are now available but you really need a Dr's
advice if you are planning to switch from such a high dose of nasal spray to
the tablets - especially considering the heart symptoms that you have
already had.

Absolutely.
Phenylephrine is a stimulant and a vasoconstrictor.  With a large enough
dose, some of it will get absorbed systemically into your bloodstream
right thru your nose (just like snorting cocaine).  And it may end up
causing both tachycardia and constricting the blood vessels in your
heart--which can be disastrous.  The symptoms you're describing fit the
combination of overstimulation and vasoconstriction exactly.

You'll have to taper off the phenylephrine.  I think you should consult
a physician who knows about this problem--the medical name is "rhinitis
medicamentosa."  He can prescribe a combination of systemic steroids
(Medrol) and steroid nasal sprays (e.g., Nasonex) to help you cope with
the withdrawal symptom of congestion till your body adjusts.  Without
these prescription meds, you may not be able to kick the habit on your
own--though you can try it and see.

Once you're off the phenylephrine, you should consult an ENT who can
finally help cure your congestion so you won't ever have to go back to
phenylephrine anymore.

Yes Phenylephrine has well-known cardiac side-effects.  You do need to get off
it.

Steven's posts are exactly correct.

The tachycardia is not necessarily of enormous consequence,  but anything to do
with your heart is more important than other things.

Yes but it alone is probably not enough to deal with the rebound congestion you
are going to experience when you start to cut back on the Phenylephrine.

You may need a short-course of gradually-decreasing prescribed oral steroids,
under the supervision of an ENT, to tide you over when you start cutting back
on the Phenylephrine.  

However, oral steroids should not casually be taken long term as they can have
even worse side-effects than the Phenylephrine, so really you will have to plot
your course carefully with the help of an ENT, as Steven suggests.....

I had racing heart and skipping heart beats when I took Sudafed PE pills
which also has Phenylephrine as an active ingredient. Quite scary to
experience! Probably should have gone to an ER but instead just waited for
it to run its course. Later found out I took the wrong dose 2 pills instead
of 1 pill like the original Sudafed (Pseudoephedrine) dose. I called the
makers of Sudafed and said their packaging was misleading (packed in
groups of 2 if you can believe it).

I think each person reacts differently to the various decongestants. I
can't believe that the doctor wouldn't think this contributed to your
symptoms. Just look at the package directions and see the warnings!

I think the suggestions to do the withdrawal under an ENT's care sound the
most likely for success. Good luck!