Has anyone had ridiculous coughing as a side effect of cancer? My friend has stage IV rectal with mets to liver and lungs. This weeks-long coughing is getting worse and I'm not having much luck with the doctors who keep saying it is a sinus infection or just a cold. I would think a sinus infection would go away with antibiotics. Any suggestions on what to take to get on top of this would be appreciated. Cough medicine is out (can't take with "excessive phlem"), cough drops do nothing, he's drinking tons of water and green tea. Thanks!