{"id":735,"date":"2026-03-12T10:38:00","date_gmt":"2026-03-12T10:38:00","guid":{"rendered":"https:\/\/services.nhslothian.scot\/neuroprogressiveanddementianetwork\/?page_id=735"},"modified":"2026-03-12T11:29:33","modified_gmt":"2026-03-12T11:29:33","slug":"top-hat","status":"publish","type":"page","link":"https:\/\/services.nhslothian.scot\/neuroprogressiveanddementianetwork\/top-hat\/","title":{"rendered":"TOP HAT"},"content":{"rendered":"\n
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Trial of Ondansetron as a Parkinson\u2019s Hallucinations Treatment.<\/h1>\n\n\n\n

TOP HAT: A Phase III multi-centre randomised double-blind placebo-controlled trial
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Project Details<\/strong><\/p>\n\n\n\n

Start Date
November 2023<\/strong><\/p>\n\n\n\n

Status
Open to Recruitment<\/strong><\/p>\n\n\n\n

Principal Investigator
Dr Gordon Duncan<\/a><\/p>\n\n\n\n

NDN Study Lead
Jessica Crossan<\/a><\/p>\n\n\n\n

Main Research Site
Western General Hospital<\/strong><\/p>\n<\/div><\/div>\n\n\n\n

This clinical trial looks to see if the medication ondansetron can help treat hallucinations associated with Parkinson\u2019s disease.<\/strong><\/p>\n\n\n\n

What Happens In This Study?<\/strong><\/p>\n\n\n\n

You will either be given a medicine called ondansetron <\/strong>or a placebo<\/strong> (a dummy pill that looks like the medicine but has no active ingredients). Neither you, nor the research team, will know which group you are in.<\/p>\n\n\n\n

Can I Join This Study?<\/strong><\/p>\n\n\n\n

To take part in this medical trial, you must meet these 6 requirements<\/strong>:<\/p>\n\n\n\n

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  1. Your Diagnosis:<\/strong> A doctor must have confirmed that you have Parkinson\u2019s disease<\/strong> OR Dementia with Lewy Bodies.<\/strong><\/li>\n\n\n\n
  2. Your Age:<\/strong> You are over 18 years old<\/strong>.<\/li>\n\n\n\n
  3. Your Symptoms:<\/strong> You must be experiencing visual hallucinations<\/strong> due to your Parkinson\u2019s disease OR Dementia with Lewy Bodies. These must have been happening at least once a week for the past month.<\/strong><\/li>\n\n\n\n
  4. Your Current Medicine:<\/strong> You must have been taking the same Parkinson’s medication for at least the last 1 month<\/strong> without making any big changes to it.<\/li>\n\n\n\n
  5. Your Time:<\/strong> You must do your best to attend all your study visits, and follow the rules of the study until it ends.<\/li>\n\n\n\n
  6. Taking the Medicine:<\/strong> You must be willing and able to swallow the trial medication.<\/li>\n<\/ol>\n\n\n\n

    Study Length<\/strong>: 24 weeks (6 months)<\/p>\n\n\n\n

    Number of appointments<\/strong>: 3 visits, plus check in phone calls<\/p>\n\n\n\n

    More information on the trial can be on the UCL website<\/a>.<\/p>\n<\/div><\/div>\n\n\n\n