Indicated for the treatment of mild to moderate dementia associated with Parkinson's disease.
Cholinesterase Inhibitor; Anti-dementia drugs
Rivastigmine is a carbamate derivative that is structurally related to physostigmine, but not to donepezil and tacrine. The precise mechanism of rivastigmine has not been fully determined, but it is suggested that rivastigmine binds reversibly with and inactivates chlolinesterase (eg. acetylcholinesterase, butyrylcholinesterase), preventing the hydrolysis of acetycholine, and thus leading to an increased concentration of acetylcholine at cholinergic synapses. The anticholinesterase activity of rivastigmine is relatively specific for brain acetylcholinesterase and butyrylcholinesterase compared with those in peripheral tissues.
Dosing in Alzheimer’s Disease: Initiate treatment with the 1.5 mg twice a day. After a minimum of 2 weeks and if well tolerated, increase the dose to 3 mg twice a day. Subsequent increases to 4.5 mg twice a day and 6 mg twice a day should be attempted after a minimum of 2 weeks at the previous dose and if well tolerated. The maximum dose is 6 mg twice a day (12 mg per day). Dosing in Parkinson’s Disease: Initiate treatment with the 1.5 mg twice a day. After a minimum of 4 weeks and if well tolerated, increase the dose to 3 mg twice a day. Subsequent increases to 4.5 mg twice a day and 6 mg twice a day should be attempted after a minimum of 4 weeks at the previous dose and if well tolerated. The maximum dose is 6 mg twice a day (12 mg per day).
As a cholinesterase inhibitor, Rivastigmine may exaggerate the effects of succinylcholine-type muscle relaxants during anaesthesia. Caution is recommended when selecting anaesthetic agents. Possible dose adjustments or temporarily stopping treatment can be considered if needed. In view of its pharmacodynamic effects, rivastigmine should not be given concomitantly with other cholinomimetic substances and might interfere with the activity of anticholinergic medicinal products. No pharmacokinetic interaction was observed between rivastigmine and digoxin, warfarin, diazepam or fluoxetine in studies in healthy volunteers. The increase in prothrombin time induced by warfarin is not affected by administration of rivastigmine. No untoward effects on cardiac conduction were observed following concomitant administration of digoxin and Rivastigmine.
Hypersensitivity to other carbamate derivatives. Severe hepatic impairment. Patients w/ sick sinus syndrome or conduction defects, resp diseases. Cholinergic stimulation may increase gastric acid secretion. May exacerbate urinary obstwction & seizures. Pregnancy. Renal impairment, mild to moderate hepatic impairment. Monitor body wt. Asthma or obstwctive pulmonary disease. May worsen extrapyramidal symptoms. Lactation.
Accidental trauma, fatigue, asthenia, dizziness, headache, somnolence, agitation, insomnia, confusion, depression, nausea, vomiting, diarrhoea, abdominal pain, loss of appetite, dyspepsia, upper resp tract infection, urinary tract infection. Rarely, angina pectoris, gastric & duodenal ulcers, GI haemorrhage; bradycardia, seizures, rashes & syncope. Senous GI reactions such as anorexia, vomiting & wt loss.
This drug should be used during pregnancy only if the benefit outweighs the risk. A decision should be made to discontinue breastfeeding or discontinue the drug, taking into account the importance of the drug to the mother.
Most cases of accidental overdose have not been associated with any clinical signs or symptoms and almost all of the patients concerned continued rivastigmine treatment. Where symptoms have occurred, they have included nausea, vomiting and diarrhoea, hypertension or hallucinations. Due to the known vagotonic effect of cholinesterase inhibitors on heart rate, bradycardia and/or syncope may also occur. Ingestion of 46 mg occurred in one case; following conservative management the patient fully recovered within 24 hours. As rivastigmine has a plasma half-life of about 1 hour and a duration of acetylcholinesterase inhibition of about 9 hours, it is recommended that in cases of asymptomatic overdose no further dose of rivastigmine should be administered for the next 24 hours. In overdose accompanied by severe nausea and vomiting, the use of antiemetics should be considered. Symptomatic treatment for other adverse reactions should be given as necessary. In massive overdose, atropine can be used. An initial dose of 0.03 mg/kg intravenous atropine sulphate is recommended, with subsequent doses based on clinical response. Use of scopolamine as an antidote is not recommended.
Store in a cool and dry place, protected from light.
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