Ghost-Pill

Introduction

A patient who is taking Glucophage XR 500 mg came to the pharmacy concerned that she had seen some tablet-like structures in her stool.

• She asked if she was still getting the full dose of medication if the tablet was not dissolving.

Facts

With some controlled-release formulations, it is expected that the empty intact shell that housed the medicine ("ghost-pill" or "ghost-tablet"), or other insoluble formulation parts will appear in the stools.

• This is because controlled-release formulations (tablets, capsules and their parts) are designed to either disintegrate slowly to release the medicine over a predetermined period or remain intact.

Examples of Medicines

Some examples of medicine that can appear in the stool include:

• Adefin XL (nifedipine)
• Cardura XL (doxazosin)
• Concerta (methylphenidate)
• Duride (isosorbide mononitrate)
• Effexor-XR (venlafaxine)
• Glucophage XR (metformin)
• Invega (paliperidone)
• Nuelin SR (theophylline)
• OxyContin (oxycodone)
• Pristiq (desvenlafaxine)
• Span-K (potassium chloride)
• Urocit-K (potassium citrate)

Patient Counselling

When prescribing these controlled-release medicines, it is important to reassure patients that the active medicine will be released, even if remnants of the medicine can appear in their stools.

• However, if the patient reports a lack of efficacy from their medication, further investigations may be warranted.

External Links

• Curse of the ghost pills: the role of oral controlled-release formulations in the passage of empty intact shells in faeces. Two case reports and a literature review relevant to psychiatry, 2013
  
• Ghost pill: knowledge and awareness of this phenomenon among health care professionals, 2014
  
• Ghosts of Medicines Passed, 2016
  
• Ghost tablet in faeces, 2017