Rivastigmin

Rivastigmin, also known as rivastigmine, is a cholinesterase inhibitor used to treat the cognitive symptoms of mild to moderate Alzheimer's disease and dementia associated with Parkinson's disease. It belongs to the carbamate class and inhibits both acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE), increasing acetylcholine levels in the brain and potentially improving memory and thinking.

It is available in oral and transdermal forms. The oral form includes capsules and a solution, while the transdermal patch delivers continuous medication over 24 hours. Dosing is typically titrated to tolerance. For Alzheimer's disease, oral dosing commonly starts at 1.5 mg twice daily, increasing gradually to 3 mg twice daily, then 4.5 mg twice daily and 6 mg twice daily as tolerated. The patch is applied once daily, with strengths around 4.6 mg/24 h or 9.5 mg/24 h; the patch should be placed on clean, dry skin and rotated to minimize irritation.

Pharmacologically, rivastigmin acts as a pseudo-irreversible inhibitor of AChE and BuChE. It is metabolized primarily by hydrolysis through cholinesterases rather than liver enzymes, with minimal involvement of cytochrome P450 pathways. Inactive metabolites are excreted in the urine.

Common adverse effects include nausea, vomiting, loss of appetite, weight loss, dizziness, and fatigue. Gastrointestinal symptoms are more frequent with oral forms, while patch use may cause local skin irritation at the application site. Caution is warranted in patients with bradycardia, conduction disorders, or bronchospastic disease, and care should be taken when co-administered with anticholinergic medicines, which can reduce its effect.

Rivastigmin was developed for symptomatic treatment of dementia and is marketed under various brand names, including Exelon, in many regions. It is approved in multiple countries for mild to moderate Alzheimer's disease and Parkinson's disease dementia.