A typical breakthrough pain episode is severe, categorized by a fast onset, typically reaches peak intensity instantly, and lasts for an average duration of about 30 min. The research work includes the use of opioid for the treatment of breakthrough pain with special emphasis on the development of rapidly dissolving sublingual film formulation of buprenorphine hydrochloride (BPH). BPH is an opioid analgesic with low oral bioavailability due to less absorption and first-pass metabolism. The clear and transparent sublingual films were prepared using a film-forming polymer (pullulan) with a plasticizer (PEG 400). The formulation was optimized statistically using 3(2) randomized full factorial design. The optimized film formulation showed desired mechanical properties (tensile strength of 25 N/m(2)) and a minimum disintegration time of 16 s. Differential scanning calorimetry and X-ray diffraction studies confirmed the uniform distribution of the drug in polymeric matrices. Morphological study showed the absence of drug crystals on polymeric surface. The relative bioavailability of the film formulation was increased by 10 % with respect to tablet formulation due to rapid T max (0.08 h for film while 0.15 h for tablet), which was confirmed by in vivo studies performed on rabbits. The present technology could be a promising alternative to conventional drug delivery systems and traditional routes of administration for breakthrough pain management.