Indications

Rivas capsules are indicated for the symptomatic treatment of:

• Mild to moderately severe Alzheimer's dementia.
• Mild to moderately severe dementia in patients with Idiopathic Parkinson's disease.

Pharmacology

Rivastigmine is a carbamate derivative that is believed to work by reversibly binding to and inactivating cholinesterase enzymes, such as acetylcholinesterase. This action prevents the breakdown of acetylcholine, leading to increased concentrations of this neurotransmitter at cholinergic synapses in the brain. The anticholinesterase activity of rivastigmine is relatively specific to the brain, with less effect on peripheral tissues.

Dosage

• Rivastigmine Capsule:
  • Initial dose: 1.5 mg twice a day.
  • Dose Titration: If the initial dose is well tolerated after at least two weeks, the dose can be increased to 3 mg twice a day. Further increases to 4.5 mg and then 6 mg twice a day can be considered after a minimum of two weeks at each dose level, based on tolerability.
  • Maintenance dose: The effective dose is 3 mg to 6 mg twice a day. The maximum recommended daily dose is 6 mg twice a day.
  • Re-initiation of therapy: If treatment is interrupted for more than several days, it should be restarted at 1.5 mg twice daily, and the dose should be titrated up again.
• Rivastigmine Transdermal Patch:
  • Initial dose: 4.6 mg/24 hours patch.
  • Dose Titration: After a minimum of 4 weeks, if tolerated, the dose can be increased to 9.5 mg/24 hours. After another 4 weeks, the dose can be increased to the maximum of 13.3 mg/24 hours.
  • Severe Alzheimer's Disease: The recommended dose is a 13.3 mg/24 hours patch.

Administration

Rivastigmine capsules should be taken twice a day with morning and evening meals.

Interaction

• Muscle Relaxants: Rivas may exaggerate the effects of succinylcholine-type muscle relaxants.
• Cholinomimetic substances and anticholinergic drugs: Rivas should not be given with other cholinomimetic substances and may interfere with anticholinergic medications.
• Other drugs: No pharmacokinetic interaction was observed with digoxin, warfarin, diazepam, or fluoxetine.

Contraindications

Rivas is contraindicated in patients with a known hypersensitivity to rivastigmine or other carbamate derivatives.

Side Effects

The most common adverse reactions are gastrointestinal, including nausea (38%) and vomiting (23%), particularly during dose titration. Female patients may be more susceptible to gastrointestinal side effects and weight loss.

Pregnancy & Lactation

There is no clinical data on the use of rivastigmine in pregnant women. Animal studies show that rivastigmine is excreted into milk, so women should not breastfeed while on this medication.

Precautions & Warnings

• Cardiac Conditions: Caution is needed for patients with sick sinus syndrome or conduction defects.
• Gastrointestinal Issues: Cholinergic stimulation can increase gastric acid secretion, so caution is advised for patients with a history of ulcers.
• Other Conditions: Use with caution in patients with asthma, obstructive pulmonary disease, urinary obstruction, or a history of seizures. It may also worsen extrapyramidal symptoms.
• Renal and Hepatic Impairment: Dosing should be carefully titrated based on individual tolerability due to increased drug exposure in these patients.
• Weight Monitoring: Body weight should be monitored.

Use in Special Populations

• Children: Rivas is not recommended for use in children.
• Renal and Hepatic Impairment: Dosing recommendations should be closely followed due to increased exposure in patients with moderate renal and mild to moderate hepatic impairment.

Overdose Effects

Most accidental overdoses are not associated with clinical symptoms. When symptoms do occur, they include nausea, vomiting, diarrhea, hypertension, or hallucinations. Due to the vagotonic effect of cholinesterase inhibitors, bradycardia (slow heart rate) and/or fainting may also occur. In cases of overdose, no further dose should be administered for 24 hours. For severe nausea and vomiting, antiemetics can be used. Atropine may be used in massive overdose.

Therapeutic Class

Rivas is a drug for dementia.

Storage Conditions

Store in a cool and dry place, protected from light.