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

Abstract

Orally taken tablets in different formulations continue to have a central role in the treatment of various psychiatric and medical conditions. In order to improve compliance, reduce the frequency of taking medications and minimize the peaks and troughs associated with certain immediate-release formulations, pharmaceutical companies have developed a number of novel methods of delivering oral solid dosage medications in the form of controlled-release (CR) formulations. Some CR formulations have been associated with pharmacobezoars and false-positive findings on certain physical investigations. Though CR drugs are commonly used in psychiatry, clinicians appear to have a limited understanding of how they are released for absorption once ingested. Some have insoluble parts that are excreted in faeces as 'ghost pills'. Due to lack of awareness of this phenomenon to both patients and the physicians, anxiety has ensued in some patients. Some clinicians have been puzzled or have been dismissive when faced with curious patients wanting to know more after they had observed tablet-like looking structures in faeces. We present two cases from our clinical setting and a few drawn from the World Wide Web to highlight the role of CR medications and their association with the ghost pill phenomenon. The mechanisms involved in drug release relevant to psychiatry medications are also briefly reviewed. The ghost pill phenomenon occurs with certain CR medications. This is a normal and expected outcome related to drug-release mechanisms of some of these products. It is inevitable that some patients will see what looks like tablets or capsules in faeces. Raising awareness of this phenomenon among clinicians would facilitate discussions and information sharing at the initial process of medication prescribing. Awareness among patients and carers would also help to allay anxiety.

Ghost pill: knowledge and awareness of this phenomenon among health care professionals

“…Without prior knowledge of the fact that this is normal for certain medications, this can result in the person being distressed, thinking that they have not been getting the prescribed dose of medications or thinking the drug may be faulty. 7,9 Pharmaceutical companies provide a lot of information on each drug to professionals. This information is contained in the SPC for each drug.…”

“…The British National Formulary (BNF) has been noted to lack information on the ghost pill too. 7 The problems may be compounded given that a significant number of nonmedical prescribers are on the increase. If similar information were provided in the BNF, it would allow clinicians and other prescribers to consult when needed.…”

“…It can be a source of anxiety, paranoia and mistrust for the uninformed patient and healthcare professionals. 7 Drugs associated with this phenomenon are widely available today. They are made in such a way that the active drug is released in a novel way, while the protective covering or certain undigested parts of the drug remains intact as the tablet or capsule traverses the gastrointestinal (GI) system.…”

“…However, despite clinicians using them over the years, anecdotal evidence suggests that few are aware that some have insoluble parts that can be visible to the naked eye when they are eventually passed out in faeces. 7 The passage of intact undigested or insoluble drug housing shells into faeces sometimes known as "the ghost pill" or "ghost-tablet" 8 occurs commonly with some SR formulations taken orally. It can be a source of anxiety, paranoia and mistrust for the uninformed patient and healthcare professionals.…”

“…As a result, some have become alarmed on seeing what looks like intact tablet or capsules in faeces. 7,9 We conducted a survey to assess the awareness of the "ghost pill" phenomenon among health care professionals in psychiatry and medicine. The term medicine would be used broadly to encompass all other specialty of medicine except psychiatry.…”