According to user comments and patients rating. Following Pain medications are more widely taken by chronic pain patients:

• Tramadol Oral   
• Opana ER Oral  
• Kadian Oral    
• Morphine Oral    
• MS Contin Oral    
• Avinza Oral    
• Ultram ER Oral
  
• Hydromorphone Oral    
  
• Oramorph SR Oral    
  
• Oxymorphone Oral    
  
• Diflunisal Oral    
  
• Prialt IT    
  
• Ziconotide IT