Type of Drug:
Reversible cholinesterase inhibitor used in managing mild to moderate Alzheimer disease-associated dementia.
How the Drug Works:
The exact mechanism is unknown. Cholinesterase inhibitors act by enhancing cholinergic function. Deterioration or loss of cholinergic neurons may be a primary cause of cognitive dysfunction associated with Alzheimer disease. Cholinesterase inhibitors may enhance cholinergic transmission in this setting. If this mechanism of action is correct, the effect of cholinesterase inhibitors may lessen as the disease advances and fewer cholinergic neurons remain functionally intact. There is no evidence that cholinesterase inhibitors alter the course of the underlying dementing process.
Uses:
To treat mild to moderate dementia of the Alzheimer type.
Precautions:
Do not use in the following situations:
- Allergy to acridine derivatives (tacrine only)
- Allergy to carbamate derivatives (rivastigmine only)
- Allergy to a cholinesterase inhibitor or any of its ingredients
- Allergy to piperidine derivatives (donepezil only)
- Treatment-associated jaundice from previous treatments (tacrine only)
Nicotine: Nicotine use increases the elimination of tacrine from the body.
Gender: Tacrine and galantamine are eliminated from the body more slowly in women.
Pregnancy: There are no adequate and well-controlled studies in pregnant women. Use only if clearly needed and the potential benefits to the mother outweigh possible hazards to the fetus.
Breastfeeding: It is not known if cholinesterase inhibitors are excreted in breast milk. Contact your doctor before you begin breastfeeding.
Children: Safety and effectiveness in children have not been established.
Elderly: Rivastigmine and galantamine are eliminated from the body more slowly in the elderly.
Lab Tests: Lab tests will be required to monitor therapy with tacrine. Tests include liver function tests every other week from at least week 4 to week 16, after which monitoring may be decreased to every 3 months, and blood counts.
Drug Interactions:
Tell your doctor or pharmacist if you are taking or if you are planning to take any over-the-counter or prescription medications or dietary supplements with a cholinesterase inhibitor. Doses of one or both drug may need to be modified or a different drug may need to be prescribed. The following drugs and drug classes interact with cholinesterase inhibitors:
- Anticholinergics (eg, atropine, scopolamine)
- Cholinergic agonists (eg, bethanechol)
- Cholinesterase inhibitors (eg, neostigmine)
- Cimetidine (eg, Tagamet)
- Food (rivastigmine only)
- Ketoconazole (eg, Nizoral)
- NSAIDs (eg, ibuprofen)
Side Effects:
Every drug is capable of producing side effects. Many cholinesterase inhibitor users experience no, or minor, side effects. The frequency and severity of side effects depend on many factors including dose, duration of therapy, and individual susceptibility. Possible side effects include:
Digestive Tract: Nausea; vomiting; diarrhea; appetite loss; stomach bleeding; black tarry stools; loss of bowel control; bloating; gas; belching; indigestion; stomach pain; weight loss; constipation.
Nervous System: Sleeplessness; fatigue; drowsiness; headache; pain; difficulty moving; dizziness; fainting; depression; abnormal dreams; abnormal thinking; hallucinations; tremors; irritability; numbness or tingling in hands or feet; abnormal skin sensations (eg, burning, prickling, tingling); aggression; feeling of whirling motion; clumsiness; twitching; restlessÂness; nervousness; anxiety; paranoia; convulsions; weakness; confusion; hostility; difficulty speaking.
Circulatory System: Chest pain; abnormal heartbeat; heart pounding; blood pressure changes; flushing; hot flashes.
Skin: Itching; hives; rash; excessive sweating; unusual bruising or bleeding.
Respiratory System: Difficulty breathing; sore throat; nasal congestion; sinus problems; runny nose; coughing; upper respiratory infection; pulmonary congestion.
Urinary and Reproductive Tract: Loss of bladder control; frequent urination; excessive urination at night; urinary tract infection; blood in the urine.
Other: Flu-like syndrome; chills; fever; general body discomfort; muscle cramps; muscle or joint pain; muscle tension; back pain; swelling in hands or feet; anemia; dehydration; eye irritation; blurred vision; elevated transaminase; accidental trauma; abnormal gait; ringing in the ears; nosebleed.
Guidelines for Use:
- Dosage is individualized. Take exactly as prescribed.
- Oonepezil- Take in the evening just before bedtime with or without food.
- Galantamine - Take during morning and evening meal if possible. Fellow recommended dosage and administration. If therapy is interrupted for several days or longer, restart treatment at the lowest dose. Nausea may be reduced by administering with food, antiemetic medication, or ensuring adequate fluid intake.
- Tacrine - Take between meals if possible; however, it may be taken with meals to avoid stomach upset. The effect of tacrine is thought to depend upon its administration at regular intervals.
- Rivastigmine capsules- Take with food in divided doses in the morning or evening.
- Rivastigmine solution - Remove the oral dosing syringe provided in its protective case and, using the provided syringe, withdraw the preÂscribed amount of rivastigmine. Each dose may be swallowed from the syringe or first mixed with a small glass of water, cold fruit juice, or soda. Stir the mixture before drinking.
- If a dose is missed, take it as soon as possible. If several hours have passed or if it is nearing time for the next dose, do not double the dose to catch up, unless advised by your doctor. If more than one dose is missed or it is necessary to establish a new dosage schedule, contact your doctor or pharmacist.
- Tacrine - Do not stop taking this medicine suddenly or change the dosÂage unless instructed to do so by your doctor. Abrupt discontinuation or large reduction in the total daily dose of tacrine may cause a decline in mental function and behavioral disturbances. Unsupervised increases in the dose of tacrine may also have serious consequences.
- Inform your doctor if you are pregnant, become pregnant, planning to become pregnant, or are breastfeeding before beginning therapy.
- Report any new or worsening side effects to your doctor.
- May cause dizziness or blurred vision. Use caution while driving or perÂforming other tasks requiring alertness, coordination, or physical dexterity.
- Rivastigmine - There is a high incidence of nausea and vomiting associated with the use of the drug, along with the possibility of anorexia and weight loss. Monitor for these adverse events and inform your doctor if they occur.
- Tacrine - Contact you doctor if you experience side effects that occur soon after taking a dose (eg, nausea, vomiting, loose stools) or develop side effects that are delayed (eg, rash, yellowing of the skin, changes in stool color).
- Lab tests will be required to monitor therapy. Be sure to keep appointments.
- Store capsules and tablets at controlled room temperature (59 to 86 F) away from moisture. Store rivastigmine solution below 77 F in an upright position. Protect from freezing.
Tagged under:alzheimer disease, drug interactions, Psychotherapeutic Agents, stomach bleeding, vomititng weight loss