ARICEPT - GENERIC

ABSTRACT Aims To conduct a preliminary evaluation of the safety and efficacy of tiagabine, sertraline or donepezil versus an unmatched placebo control as a treatment for cocaine dependence. Design A 10-week out-patient study was conducted using the Cocaine Rapid Efficacy and Safety Trial (CREST) study design. Setting This study was conducted at the Cincinnati Medication Development Research Unit (MDRU) and at an affiliated site in Dayton, Ohio. Participants Participants met Diagnostic and Statistical Manual version IV (DSM-IV) criteria for cocaine dependence. Sixty-seven participants were enrolled with 55 completing final study measures. Intervention The targeted daily doses of medication were tiagabine 20 mg, sertraline 100 mg and donepezil 10 mg. All participants received 1 hour of manualized individual cognitive behavioral therapy on a weekly basis. Measurements Primary outcome measures of efficacy included urine benzoylecgonine (BE) level, Cocaine Clinical Global Impression Scale-Observer and self-report of cocaine use. Safety measures included adverse events, ECGs, vital signs and laboratory tests. Findings Subjective measures of cocaine dependence indicated significant improvement for all study groups. Generalized estimating equations analysis indicated that the tiagabine group showed a trend toward a significant decrease in urine BE level from baseline to weeks 5-8 (P = 0.10) and non-significant changes for the other study groups. No pattern of physical or laboratory abnormalities attributable to treatment with any of the medications was identified. There were three serious adverse events reported, none of which were related to study procedures. Conclusions The present findings suggest that tiagabine may be worthy of further study as a cocaine dependence treatment.

OBJECTIVE: To report 2 cases of patients with Down syndrome and severe cognitive impairment who gained dramatic improvements in quality of life (QOL) upon donepezil treatment. CASE SUMMARIES: Case 1. A 38-year-old woman with Down syndrome, diagnosed with secondary progressive dementia when her mental state had deteriorated rapidly after graduation from junior high school, started donepezil treatment. The loading dose was 3 mg/day and was increased to 5 mg/day for maintenance. One month after the dose was increased, adverse effects such as soft stool and urinary incontinence appeared. These adverse effects disappeared when the dose was decreased again to 3 mg/day. Her QOL improved dramatically with this minimal dose. She recovered verbal and written communication skills that she had lost for the past 21 years. Case 2. A 22-year-old man with Down syndrome, who had been diagnosed as having severe mental retardation, was put on donepezil therapy. Both loading and maintenance doses were 3 mg/day. His QOL had also dramatically improved, with some recovery in verbal communication. Transient agitation/violence and transient muscle weakness appeared during the first few months of treatment. DISCUSSION: Patients with Down syndrome may be more sensitive to donepezil therapy than others and may benefit from this medicine, although they may also have adverse effects more frequently. CONCLUSIONS: Donepezil may be a useful medicine for some patients with Down syndrome with severe cognitive impairment or mental retardation if the adverse effects are manageable.

RATIONALE: APP23 mice are a promising model of Alzheimer's disease, expressing several histopathological, cognitive and behavioural hallmarks of the human condition. A valid animal model should respond to therapeutic interventions in an equivalent manner as human patients. OBJECTIVES: To further validate the APP23 model, we examined whether cognitive deficits could be antagonised by donepezil, rivastigmine, galantamine or memantine, which are approved drugs for symptomatic treatment of dementia. METHODS: Animals were tested at an age at which untreated APP23 mice display severe deficits in visual-spatial learning. Four-month-old APP23 mice and control littermates were administered donepezil (0.3 or 0.6 mg kg(-1)), rivastigmine (0.5 or 1.0 mg kg(-1)), galantamine (1.25 or 2.5 mg kg(-1)), memantine (2 or 10 mg kg(-1)) or saline through daily i.p. injections. After 1 week of treatment, acquisition phase commenced, with daily treatment continuing during cognitive testing. RESULTS: All cholinesterase inhibitors reduced cognitive deficits with the following optimal daily doses: galantamine 1.25 mg kg(-1), rivastigmine 0.5 mg kg(-1) and donepezil 0.3 mg kg(-1). Higher dosages often did not exert beneficial effects in accordance with inverted U-shaped dose-response curves described for cholinomimetics. Symptomatic efficacy of memantine on cognition was mild, with significant amelioration manifesting during probe trial. CONCLUSIONS: This is the first study to simultaneously evaluate the efficacy of therapeutically relevant doses of these four compounds in one particular learning and memory paradigm, being the Morris water maze. The fact that symptomatic intervention was able to diminish cognitive impairment, substantially adds to the validity of the APP23 model as a valuable tool to evaluate future therapeutic approaches.

BACKGROUND: Tardive dyskinesia and other delayed-onset abnormal involuntary movement disorders may occur as a result of the use of psychotropic drugs. A distinction is usually made between classic tardive dyskinesia (TD) (orobuccal-lingual-facial) and tardive dystonia, tardive tremor (TT), tardive akathisia, and other related syndromes. In spite of the development of atypical antipsychotics with fewer side effects, tardive movement disorders nevertheless continue to present a significant clinical and therapeutic challenge. Several reports have suggested that donepezil may be helpful in the treatment of TD. METHOD: A preliminary study was conducted of 7 patients (5 women and 2 men) enrolled over a period of 6 months who had been experiencing TT for a period of at least 1 year. The ages of the patients ranged from 64 to 79 years, and all patients were on stable antipsychotic therapy. Donepezil was added to their usual treatment for 8 weeks. The severity of patients' extrapyramidal symptoms was assessed using the tremor subscale of the Simpson-Angus Scale (SAS) and self-rated with a modification of the Clinical Global Impressions scale, the Subjective Clinical Improvement Impression scale. The clinical response was evaluated by comparing the rating scores at baseline prior to donepezil treatment and every 2 weeks thereafter. RESULTS: The addition of donepezil (up to 10 mg/day) was associated with a clinically significant improvement (from 37.5% to 63.6%) on the SAS tremor subscale following 4 weeks of therapy. Only 1 patient discontinued follow-up due to side effects. CONCLUSION: The results suggest that donepezil may be effective in the treatment of TT, and this finding should be evaluated further by a randomized controlled study.

GENERIC NAME: donepezil
BRAND NAME: Aricept

DRUG CLASS AND MECHANISM: Donepezil is an oral medication used to treat Alzheimer's disease. It belongs to a class of drugs called cholinesterase inhibitors that also includes tacrine (Cognex). Scientists believe that Alzheimer's disease may result from a deficiency in chemicals (neurotransmitters) used by nerves in the brain to communicate with one another. Donepezil inhibits acetylcholinesterase, an enzyme responsible for the destruction of one neurotransmitter, acetylcholine. This leads to increased concentrations of acetylcholine in the brain, and the increased concentrations are believed to be responsible for the improvement seen during treatment with donepezil. Donepezil improves the symptoms but does not slow down the progression of Alzheimer's disease. Donepezil was approved by the FDA in 1996.

PREPARATIONS: 5 and 10 mg tablets.

STORAGE: Tablets should be stored at room temperature, 15-30°C (59-86°F).

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

DOSING: Donepezil is generally taken once daily at night prior to retiring. Its absorption is not affected by food so that it may be taken with or without food.

DRUG INTERACTIONS: Drugs with anti-cholinergic properties that can cross into the brain, such as atropine, benztropine (Cogentin), and trihexyphenidyl (Artane) counteract the effects of donepezil and should be avoided during therapy with donepezil.

Donepezil is metabolized (eliminated) by enzymes in the liver. The rate of metabolism of donepezil may be increased by medications that increase the amounts of these enzymes, such as carbamazepine (Tegretol), dexamethasone (Decadron), phenobarbital, phenytoin (Dilantin), and rifampin (Rifadin). By increasing elimination, these drugs may reduce the effects of donepezil.

Ketoconazole (Nizoral) has been shown to block the enzymes in the liver that metabolize donepezil. Therefore, concurrent use of ketoconazole and donepezil may result in increased concentrations of donepezil in the body and possibly lead to donepezil side effects. Quinidine (Quinidex, Quinaglute) also has been shown to inhibit the enzymes that metabolize donepezil and may cause donepezil side effects.

PREGNANCY: It is not known whether donepezil is harmful to the fetus. Safe use during pregnancy has not been established.

NURSING MOTHERS: It is not known whether the donepezil is secreted into breast milk or if breast-feeding while taking donepezil is safe for the nursing infant.

SIDE EFFECTS: The most frequently reported side effects associated with donepezil include headache, generalized pain, fatigue, dizziness, nausea, vomiting, diarrhea, loss of appetite, weight loss, muscle cramping, joint pain, insomnia, and increased frequency of urination.

Recommended dosage

ADULTS

The usual starting dose is 5 milligrams once a day at bedtime for at least 4 to 6 weeks. Do not increase the dose during this period unless directed. The doctor may then change the dosage to 10 milligrams once a day if response to the drug warrants it.

CHILDREN

The safety and effectiveness of Aricept have not been established in children.

Overdosage

Any medication taken in excess can have serious consequences. If you suspect an overdose, seek medical attention immediately.

· Symptoms of Aricept overdose include:
Collapse, convulsions, extreme muscle weakness (possibly ending in death if breathing muscles are affected), low blood pressure, nausea, salivation, slowed heart rate, sweating, vomiting

Caution! Before starting to take this medicine, it is vital that you should consult your doctor! Do not use it on your own initiative, without medical advice.