Hallucinations are a sign that the underlying disease has progressed to a stage where sensitivity to the medication increases. Hallucinations often fill a void and are frequently composed of memories. This can manifest as a person sitting in an otherwise empty chair. The images of the person are often very clear and realistic, although they may be more dream-like with surreal content. The images retrieved from the brain’s memory bank are stored in one place, whilst sounds are stored in another. Visual hallucinations are therefore always silent and do not respond when spoken to, which can be a way of clarifying that it is a hallucination.
It is therefore not just the medication that causes hallucinations – it is fundamentally the disease itself. Treatment of hallucinations involves explaining the concepts involved, simplifying the medication regimen, and reducing the total amount of medication.
You should gradually reduce or stop taking the long-acting depot preparations of Sifrol/pramipexole Depot, ReQuip/ropinirole Depot, and NeuPro/rotigotine. This applies to medicines with anticholinergic properties (Norflex, Parkopan, Disipal) and other agents such as Dinetrel (amantadine). The next step is to reduce the total dose of L-dopa and other long-acting agents such as MAO-B inhibitors, particularly if Eldepryl/selegiline has been used, but also Xadago/safinamide/rasagiline, and to discontinue COMT inhibitors. This means that pure L-dopa is usually retained as the most important anti-Parkinson’s medication and cannot be discontinued entirely.
Another approach is to add medications that counteract hallucinations. There are several medications and strategies available. Medications that enhance the effects of acetylcholine, a key neurotransmitter in the brain, such as rivastigmine, can reduce hallucinations. Another approach is to block some of the effects of dopamine using a neuroleptic. There are two that can be administered without worsening the symptoms of Parkinson’s disease – quetiapine and clozapine.
Both are effective but cause drowsiness initially, and doses usually need to be increased gradually. Clozapine carries a very small risk of seriously affecting the production of white blood cells in the bone marrow, which is why it is necessary to monitor blood counts over a long period. /Håkan Widner