I'll address two points.

1) 4-6 days is not very long for a sinus infection to clear.  You don't
say whether you've tried frequent saline irrigation, along with
decongestants and/or mucus thinners.  If not, I'd try that before taking
antibiotics.  In my experience, it takes at least 30 days of them to
clear an infection; less may just piss it off and make it resistant to
the drugs.

2)  For answers to questions about drug interactions, check out rxlist.com

Susan

You need to ask your doctor or pharmacist, but I *think* you should be
all right.  (These days, CVS and Walgreens have drug interactions on
their computers and can check quickly.)  I wouldn't use either one for a
sinus infection though.  Why aren't you seeing a doctor if you're sick?

Now, for my world-famous (ha-ha) lecture on Drug Interactions 101:

Chemically, Zithromax is a funny beast.  Technically it's in the same
category as Biaxin and erythromycin, but its unique chemical structure
causes it to have fewer interactions with Seroquel than either Biaxin or
erythromycin would.

If you want to learn more about the magic of drug interactions, surf the
Internet and study up on an enzyme system called "Cytochrome P450."
This class of about ten different enzymes is needed to metabolize
certain drugs and get them out of your system, so they don't build up in
your body every time you take the next dose.

Erythromycin (or Biaxin) inhibits the action of Cytochrome P450 3A4, an
enzyme needed for the metabolism of Seroquel.  (Zithromax does NOT
inhibit that enzyme.)  That's why those two drugs, erythromycin and
Seroquel, cannot be taken together (unless you cut way back on your dose
of Seroquel).  With that enzyme inhibited, the blood level of Seroquel
will continue to rise in your body every time you take another dose.

That's how this game is played:  Some drugs and foods *inhibit* certain
P450 enzymes.  Some other drugs and foods *potentiate* certain P450
enzymes, and yet other drugs like Seroquel *need* to be metabolized by
one of those enzymes (Seroquel is a so-called enzyme "substrate").

So that's how the game is played:  Take a P450 inhibitor of some enzyme
X with a P450 substrate of X, and the substrate will build up in your
body, causing side effects.  Take a potentiator of X with a substrate of
X, and the substrate will be metabolized too quickly, so you get a less
effective dose in your body.  And here's the chart:

http://medicine.iupui.edu/flockhart/table.htm