Rivastigmine
Rivastigmine (中文: 利凡斯的明) is a reversible acetylcholinesterase inhibitor. Rivastigmine is selective for the CNS and is used for the treatment of mild to moderate dementia associated with Parkinson’s disease.
Pronunciation
Rivastigmine 1.5mg (EXELON 1.5mg)
Rivastigmine 3mg (EXELON 3mg)
Rivastigmine 4.5mg (EXELON 4.5mg)
Mechanism of Action
Acetylcholinesterase inhibiting drug.
| Generic Name
藥名 |
HA Code 藥物代碼 | Classification藥物分類 |
|---|---|---|
| Rivastigmine Cap 1.5 mg | RIVA01 | P1S1S3 |
| Rivastigmine Cap 3 mg | RIVA02 | P1S1S3 |
| Rivastigmine Cap 6 mg | RIVA04 | P1S1S3 |
Dosage
The drug can be administered orally or via a transdermal patch; the latter form reduces the prevalence of side effects, which typically include nausea and vomiting.
By Oral
- initially 1.5 mg twice daily, increased in steps of 1.5 mg twice daily at intervals of at least 2 weeks according to response and tolerance.
- Usual range 3-6 mg twice daily.
- Maximum 6 mg twice daily.
- If treatment interrupted for more than several days, treatment should be retitrated from 1.5 mg twice daily.
Transdermal patches delivering 4.6, 9.5, or 13.3 mg of rivastigmine over 24 hours are also available for once-daily application.
Transdermal application
- initially apply 4.6 mg/24 hours patch to clean, dry, non-hairy, non-irritated skin on back, upper arm, or chest, removing after 24 hours.
- It should not be applied to the abdomen or thigh due to decreased bioavailability.
- Re-application to the same site should be avoided for 14 days.
- Only one patch should be applied at a time.
If well tolerated, increase to 9.5 mg/24 hours patch daily.
After a further 6 months if well tolerated and cognitive deterioration or functional decline are shown, the dose can be increased to 13.3 mg/24 hours patch daily.
However, for patients with a body weight below 50 kg, a maintenance dose of 4.6 mg/24 hours daily may be sufficient.
Conversion of oral rivastigmine to patches are as follows
- Those taking ≤ 6 mg daily of oral rivastigmine may be switched to 4.6 mg/24 hours patch.
- Those taking more than 6 mg daily may be switched to 9.5 mg/24 hours patch.
- The first patch should be applied on the day following the last oral dose.
Clinical benefit should be assessed on a regular basis.
How quickly dose Rivastigmine patch work?
Rivastigmine may take as long as 12 weeks to begin working and individual response to this medication will vary.
Side Effects
Significant gastrointestinal side effects include
- Nausea and vomiting
- Loss of appetite
- Weight loss
- Diarrhea
Serious side effects may include:
- Abnormal heart rhythms
- Difficulty emptying urine from the bladder
- seizures
Pharmacokinetics
| Oral bioavailability | Donepezil hydrochloride is rapidly and well absorbed from the gastrointestinal tract. Plasma protein binding is about 40%. |
|---|---|
| Onset of action | Peak plasma levels in about one hour after ingestion. Absorption from transdermal patches is slow and peak plasma concentrations are reached in 10 to 16 hours after applying the first patch; with subsequent patches, peak concentrations are reached in about 8 hours. |
| Metabolism | Primarily metabolized through hydrolysis. Minimal metabolism occurs via the cytochrome P450. |
| Elimination half-life | 1.5 hours after oral doses and about 3 hours after patch removal. |
Drug Management
Monitoring
- acetylcholinesterase inhibitor may increase gastric acid secretion, so patients should be monitored closely for GI bleeding, especially those receiving concurrent NSAID drugs.
- check body weight regularly
- monitor the cognitive, global functions, and ADL activities
- monitor the sleeping quality
Caution
- Cardiovascular conduction disorders such as sick-sinus syndrome
- Susceptibility to peptic ulcers
- Asthma, chronic obstructive pulmonary disease
- People who have a predisposition to seizures
- Concomitant antipsychotic treatment – increased risk of neuroleptic malignant syndrome
Contraindications
Patients with known hypersensitivity to rivastigmine.
Hepatic impairment
Titrate according to individual tolerability in mild to moderate impairment; use with caution in severe impairment.
Renal impairment
Titrate according to individual tolerability
Effects on ability to drive and use machinery
Rivastigmine can cause fatigue, dizziness and muscles, mainly when initiating or increasing the dose. The treating doctor should routinely evaluate the ability of patients on donepezil to continue driving or operating complex machines.
FAQ
How should I take Rivastigmine?
If you are taking the capsules, swallow them whole with a full glass of water, with your morning and evening meals. Do not open or crush the capsules.
If you are using the patch, apply it to a clean, dry and hairless skin area on your upper or lower back, upper arm, or chest. Do not put the patch over rashes, cuts, or irritated skin. Do not apply to the same area for 14 days.
How often do I change Rivastigmine Patch?
Change the patch every 24 hours around the same time.
What should I avoid while taking?
Avoid abruptly discontinue the medication.
What happen if I overdose?
Contact your primary care doctor. If emergency situation, call 999
What happen if I miss a dose?
Take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.
