Rivastigmine

GENERIC NAME: rivastigmine

DRUG CLASS AND MECHANISM
Rivastigmine is an oral medication used to treat patients with Alzheimer's disease. Rivastigmine is in a class of drugs called cholinesterase inhibitors that also includes tacrine (Cognex), donezepil (Aricept), and galantamine (Razadyne - formerly known as Reminyl). Cholinesterase inhibitors inhibit (block) the action of acetylcholinesterase, the enzyme responsible for the destruction of acetylcholine. Acetylcholine is one of several neurotransmitters in the brain, chemicals that nerve cells use to communicate with one another. Reduced levels of acetylcholine in the brain are believed to be responsible for some of the symptoms of Alzheimer's disease. By blocking the enzyme that destroys acetylcholine, rivastigmine increases the concentration of acetylcholine in the brain, and this increase is believed to be responsible for the improvement in thinking seen with rivastigmine. For most patients who take rivastigmine there will not be a dramatic improvement, but the progression of symptoms may be slowed. After six months of treatment with rivastigmine, 25-30% of patients scored better on tests of memory, understanding, and activities of daily living as compared with only 10-20% of patients receiving placebo (a dummy or sugar pill). Rivastigmine was approved by the FDA in 1998.

PRESCRIPTION: Yes

GENERIC AVAILABLE: No

PREPARATIONS: Capsules: 1.5 mg (yellow), 3 mg (orange), 4.5 mg (red) and 6 mg (orange and red).

PRESCRIBED FOR: Rivastigmine is used for the treatment of mild to moderate dementia of the Alzheimer's type.

DOSING
Rivastigmine usually is taken twice daily with meals. Due to gastrointestinal side effects that can be seen early in therapy, rivastigmine therapy is generally started at a low dose, often 1.5 mg twice daily, and gradually increased not more than once every 2 weeks. The goal usually is 6 mg twice daily. If a patient develops severe gastrointestinal side effects such as upset stomach and vomiting, he or she may need to stop taking rivastigmine for a few doses and then start taking it again at the same dose or a lower dose.

DRUG INTERACTIONS
Drugs with anticholinergic effects and which cross into the brain, such as atropine, benztropine (Cogentin), and trihexyphenidyl (Artane) oppose the effects of rivastigmine and should be avoided during therapy with rivastigmine.

Unlike donepezil (Aricept), rivastigmine does not cause the blood levels of other medications to rise and increase their risk for side effects.

PREGNANCY
Studies in pregnant rats and rabbits with high doses of rivastigmine failed to show effects on the offspring; however, no studies have been performed in pregnant women. Therefore, physicians must weigh the potential benefit of prescribing rivastigmine to pregnant women against the potential risks to the fetus.

NURSING MOTHERS
It is not known if rivastigmine is secreted in breast milk.

SIDE EFFECTS
About one-half of patients who take rivastigmine become nauseated, and about one-third vomit at least once, most commonly during the first few weeks of treatment as the dose is slowly increased. Between one in five and one in four patients lose weight during rivastigmine therapy (about 7 to 10 pounds, on average). One in six patients experiences a loss of appetite. About one in fifty patients develops dizziness. Overall, 15% of patients (between one in seven and one in six) discontinue therapy due to side effects.

USES
Rivastigmine is used to treat Alzheimer's disease.

HOW TO USE
Take this medication by mouth, usually twice daily in the morning and evening with food, or take as directed by your doctor. The dose depends on your condition and your response to the drug. If you stop taking rivastigmine for several days, consult your doctor or pharmacist before restarting the medication. Your dosage should be reduced to minimize the chance of developing very severe vomiting. Your dosage should then be increased gradually. Follow all your doctor's dosing instructions exactly.

SIDE EFFECTS
Nausea, vomiting, stomach pain, diarrhea, dizziness, or drowsiness may occur. If any of these effects persist or worsen, contact your doctor or pharmacist promptly. Tell your doctor immediately if any of these serious side effects occur: weight loss or loss of appetite. Tell your doctor immediately if any of these unlikely but serious side effects occur: unusual sweating, weakness, chest pain, swelling, mental/mood changes. Tell your doctor immediately if any of these highly unlikely but serious side effects occur: painful urination, change in the amount of urine, black stools, seizures, unusually slow heart rate. If you notice other effects not listed above, contact your doctor or pharmacist.

PRECAUTIONS
Tell your doctor your medical history, especially of: stomach or intestinal problems (e.g., ulcers, bleeding), eating disorders (e.g., anorexia nervosa), heart problems (e.g., sick sinus syndrome), lung problems (e.g., asthma, obstructive pulmonary disease), seizures, urinary tract problems (e.g., obstruction), allergies (especially drug allergies). This drug may make you dizzy or drowsy. Use caution engaging in activities requiring alertness such as driving or using machinery. Avoid alcoholic beverages. This medication should be used only when clearly needed during pregnancy. Discuss the risks and benefits with your doctor. It is not known if this medication passes into breast milk. Consult your doctor before breast-feeding.

OVERDOSE
If overdose is suspected, contact your local poison control center or emergency room immediately. US residents can call the US national poison hotline at 1-800-222-1222. Canadian residents should call their local poison control center directly. Symptoms of overdose may include: severe nausea, dizziness, weakness, increased sweating or salivation, trouble breathing, seizures, unusually slow heart rate.

MISSED DOSE
If you miss a dose, use it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.

STORAGE
Store at room temperature below 77 degrees F (25 degrees C) away from light and moisture.

Note : This product information is intended only for residents of the India. Taj Pharmaceuticals Limited, medicines help to treat and prevent a range of conditions—from the most common to the most challenging—for people around the world.