Q: Why "Nitro" drip is always supplied in glass bottle with special tubing?

Answer: Nitroglycerin binds to soft plastics bags and tubings which commonly contains polyvinylchloride (PVC). According to pharmacy literature, about 80% of the drug can be lost by this adsorption. Nitroglycerin should be given in glass and stiff polyethylene tubing. This could very well be the cause if patient requires high dose for effective clinical response*, though nitrate tolerance is another major reason if causes for adsorption is eliminated.


* Some central venous catheters may be made out from  PVC.