Cold Symptoms - what can I do to abonish persistant sinusitis when I am on venlafaxine xr and lith?

You should see your doctor.

Your doctor will be able to determine if there are any other problems. If there is a bacterial infection present, you will need antibiotics. If the sinusitis is caused by allergies, you can be prescribed a steroid nasal spray.
Surgery may be needed in severe cases of sinusitis.

You can also take over-the-counter painkillers to ease the pain. Sinus medications containing decongestants such as phenylephrine should not be taken by patients taking venlafaxine.

For more information see
from http://www.drugs.com/enc/sinusitis-chronic.html