Rivastigmine explained

What Rivastigmine is

Rivastigmine (Exelon, also generic) is a Cholinesterase Inhibitor that increases brain acetylcholine. It inhibits both acetylcholinesterase and butyrylcholinesterase, the latter being a slight pharmacological difference from Donepezil and Galantamine. In practice, the clinical effect is similar.

Rivastigmine is licensed for mild to moderate Alzheimer's Disease and for Parkinson's Disease Dementia. It is also widely used in Dementia with Lewy Bodies, where evidence supports good benefit.

The patch advantage

The skin patch is the most-used formulation in the UK because it produces steadier blood levels and substantially fewer gastrointestinal side effects than the capsule. The patch is changed once a day and produces 24-hour drug delivery.

Dosing

Patch

• Week 1 to 4: 4.6 mg per 24 hours patch;
• Week 5 onwards: 9.5 mg per 24 hours;
• If further benefit sought and tolerated: 13.3 mg per 24 hours.

The patch is applied to clean, dry skin on the upper back, chest or arm. The site is rotated daily to avoid skin reaction.

Capsule and oral solution

• Start: 1.5 mg twice daily;
• Increase by 1.5 mg twice daily every 2 to 4 weeks;
• Target: 3 to 6 mg twice daily.

Effectiveness

Rivastigmine has similar overall efficacy to Donepezil and Galantamine in Alzheimer's Disease. In Dementia with Lewy Bodies and Parkinson's Disease Dementia, benefit is often greater than in Alzheimer's, with measurable improvement in attention, hallucinations and global function in many people.

Side effects

The standard Cholinesterase Inhibitor profile applies (nausea, diarrhoea, dizziness, slowed heart rate). The patch substantially reduces gastrointestinal side effects compared with the capsule.

Patch-specific issues:

• Skin reaction at the patch site (rotate site daily);
• Patch falling off (uncommon; can occur in warm or active conditions).

When Rivastigmine may be preferred

• Gastrointestinal intolerance of oral Cholinesterase Inhibitors (the patch usually solves this);
• Established Dementia with Lewy Bodies or Parkinson's Disease Dementia (specifically licensed and well evidenced);
• Swallowing difficulty (the patch removes the need to swallow tablets);
• Carer-administered medication where supervision is easier with a daily patch.

Monitoring and review

Standard 3-month and 6- to 12-monthly review applies. The review assesses tolerability, response, skin condition at patch sites, pulse and blood pressure.

Switching to or from Rivastigmine

Switching between Cholinesterase Inhibitors is straightforward under prescriber guidance. A common scenario is switching from Donepezil capsule to Rivastigmine patch when nausea is intolerable; this often substantially improves quality of life.