[Effect pf anti-dementia drugs on the daily routine and attitude of dementia patients]

The introduction of acetylcholinesterase inhibitors has greatly improved therapeutic opportunities for patients with dementia, in particular with Alzheimer's disease. The most likely outcome of treatment with these compounds is a maintenance of cognitive ability and/or activities of daily living over at least 6 months. Regarding the progressive nature of the underlying neurodegenerative process a temporary stabilization of symptoms is a clear treatment success. Approximately 25 per cent of patients experience a significant improvement in cognitive ability. They show more attentiveness, interest, activity, orientation, communicative ability, as well as better memory. In addition, the new medications can ameliorate non-cognitive symptoms including apathy, agitation, delusions, hallucinations, and disinhibition. Open-label long-term studies have demonstrated that patients receiving treatment with an acetylcholinesterase inhibitor cross their baseline cognitive ability at week 40 to 50 and continue to decline thereafter. In spite of this slow deterioration treated patients perform better than untreated individuals. Since ethical reasons do not permit to include placebo control groups in long-term trials it is not known presently how long the benefit from treatment lasts.

Pituitary-adrenal cortical responses to low-dose physostigmine and arginine vasopressin administration in normal women and men

Animal studies indicate that central cholinergic neurotransmission stimulates CRH secretion, but several human studies suggest that the hypothalamo-pituitary-adrenal cortical (HPA) axis may be activated only by doses of cholinergic agonists that produce noxious side effects and, by inference, a nonspecific stress response. Physostigmine (PHYSO), a reversible cholinesterase inhibitor, was administered to normal women and men at a dose that elevated plasma ACTH1-39, cortisol, and arginine vasopressin (AVP) concentrations but produced few or no side effects. Exogenous AVP also was administered alone and following PHYSO, to determine if it would augment the effect of PHYSO on the HPA axis. Fourteen normal women and 14 normal men matched to the women on age and race underwent four test sessions 5 to 7 days apart: PHYSO (8 micrograms/kg i.v.), AVP (0.08 U/kg i.m.), PHYSO plus AVP, and saline control. Serial blood samples taken before and after pharmacologic challenge were analyzed for ACTH1-39, cortisol, and AVP. PHYSO and AVP administration produced no side effects in about half the subjects and mild side effects in the other half, with no significant female-male differences overall. There also were no significant female-male differences in ACTH1-39 or cortisol responses to AVP. In contrast, the men had significantly greater ACTH1-39 responses to PHYSO administration than did the women. The endogenous AVP response to PHYSO also was significantly greater in the men than in the women, and the ACTH1-39 and AVP responses to PHYSO were significantly correlated in the men (both = +0.70) but not in the women. None of the hormone responses was significantly correlated with the presence or absence of side effects in either group of subjects. These results indicate a greater sensitivity of the HPA axis to low-dose PHYSO in normal men than in normal women, which likely is mediated by increased secretion of AVP. The lack of difference in side effects between the two groups of subjects and the lack of significant correlations between presence or absence of side effects and hormone responses in either group suggest that the increased hormone responses in the men were due to increased responsivity of central cholinergic systems and not to a nonspecific stress response.

Double-blind, randomized, placebo-controlled clinical trial on the efficacy and tolerability of a physostigmine patch in patients with senile dementia of the Alzheimer type

Owing to the pharmacokinetic properties of physostigmine when administered by conventional routes, long-term cholinergic treatment of Alzheimer's disease is difficult to manage. In order to overcome the problems associated with the oral and intravenous application of physostigmine, and to improve patients' compliance, a transdermal therapeutic system was developed. The efficacy and tolerability of this system were evaluated in a double-blind, randomized, multicenter study comparing patches containing 30 mg and 60 mg physostigmine with a placebo patch. The clinical trial followed the basic principles of the various guidelines on the evaluation of anti-dementia drugs, and included patients with mild to moderate probable Alzheimer's disease. A total of 204 patients with probable Alzheimer's disease were included in the study. Of these, 136 patients were eligible for the according-to-protocol analysis of efficacy, 167 subjects for the intention-to-treat analysis of efficacy, and 181 patients were included in the safety analysis. In contrast to the hypothesis to be tested, the efficacy of physostigmine was not superior to that of placebo after a treatment period of 24 weeks. On the contrary, there was even a slight, but not statistically significant, trend toward a better outcome in the placebo group. Median physostigmine plasma concentrations of approximately 100 pg/ml were measured, showing a high degree of interindividual variability and no linear dose relationship between the 30 mg and 60 mg dosages. Plasma cholinesterase activity was not significantly affected by physostigmine. The physostigmine patch application in doses of 30 mg and 60 mg apparently did not lead to physostigmine plasma concentrations that were sufficient to compensate for cholinergic deficiencies in affected brain areas and produce clinical benefits. Both the drug and the transdermal system were generally well tolerated under the study conditions. Modifications of the patch system may perhaps make it possible to achieve higher physostigmine plasma concentrations, which seem to be required to induce the expected beneficial effects during long-term treatment of Alzheimer's disease.

Neuroendocrine responses to intravenous infusion of physostigmine in patients with Alzheimer disease

We have reported that physostigmine, a reversible cholinesterase inhibitor, enhances verbal memory in patients with Alzheimer disease (AD). To elucidate the mechanism of cognition enhancement, plasma hormones were measured during high-dose acute and low-dose chronic steady-state intravenous infusions of physostigmine in nine subjects with AD. High-dose hormone responses were measured during and for 24 h after the infusion of physostigmine 1-1.5 mg over 45-60 min. Chronic responses were measured during continuous intravenous infusions of physostigmine at doses (0.5-25 mg/day) that escalated over 2 weeks, and then during 1 week infusion of the dose that optimized cognition (2-12 mg/day) or placebo administered in a randomized, double-blind, cross-over design. A replicable improvement in verbal memory was found in five subjects. High-dose physostigmine infusion that produced noxious side effects resulted in significant elevation above baseline in plasma levels of adrenocorticotrophic hormone (ACTH) (p = 0.0001), cortisol (p = 0.0001), and beta-endorphin (p = 0.0001). Chronic physostigmine administration, in the absence of adverse effects, produced no significant elevation in ACTH (p = 0.08), cortisol (p = 0.70), or beta-endorphin (p = 0.82). These results indicate that high-dose physostigmine activates the hypothalamic-pituitary-adrenal (HPA) axis, likely representing a "stress response." In contrast, cognition-enhancing doses do not produce a peripheral corticosteroid response. Thus, physostigmine-induced memory improvement is independent of the activation of the HPA axis.

Efficacy and safety of eptastigmine for the treatment of patients with Alzheimer's disease

OBJECTIVE

To evaluate the efficacy and safety of eptastigmine in patients with moderate to moderately severe AD.

BACKGROUND

Eptastigmine is a centrally acting cholinesterase inhibitor.

METHODS

The study was carried out according a multicenter, randomized, double-blinded, placebo-controlled, parallel-group design. Patients received a 24-week treatment with placebo or eptastigmine 15 mg or 20 mg three times daily after a 4-week, stepwise dose escalation. The effects of treatment on cognition, global function, and activities of daily living were evaluated with the Alzheimer's Disease Assessment Cognitive Subscale (ADAS-Cog), the Clinician's Interview-Based Impression of Change Plus (CIBIC-Plus), and the Instrumental Activities of Daily Living scale (IADL), respectively.

RESULTS

Thirty-six centers recruited 491 patients: 164 on placebo, 166 on eptastigmine 15 mg three times daily, and 161 on eptastigmine 20 mg three times daily. Percentages of patients completing double-blinded treatment were 87% in the placebo group and 86% in both the eptastigmine-treated groups. At the end of treatment, the intent-to-treat analysis on 463 patients showed a dose-dependent effect of eptastigmine on all efficacy variables, with a statistically significant effect of the 20 mg three times daily dose compared with placebo on the ADAS-Cog, CIBIC-Plus, and IADL. Patients on eptastigmine 15 mg three times daily performed significantly better than placebo-treated patients only on the ADAS-Cog. Eleven patients on placebo (7%), 13 patients on eptastigmine 15 mg three times daily (8%), and 12 patients on eptastigmine 20 mg three times daily (8%) discontinued study treatment because of adverse events. Adverse events were recorded in 49% of patients on placebo compared with 54% on eptastigmine 15 mg three times daily and 48% on eptastigmine 20 mg three times daily. Cholinergic side effects (nausea, vomiting, diarrhea, and abdominal pain) were reported with similar frequency in the eptastigmine- and placebo-treated patients. There was a dose-dependent transient and mild neutropenic effect associated with eptastigmine treatment, and one patient on 20 mg three times daily had an asymptomatic pancytopenia.

CONCLUSIONS

Eptastigmine produces significant cognitive, clinical, and functional benefits in patients with probable AD. Although the cholinergic tolerability of eptastigmine was found to be favorable, its potential adverse hematologic effects limit its clinical utility.

Two-year treatment of Alzheimer's disease with eptastigmine. The Eptastigmine Study Group

The effectiveness of long-term treatment of Alzheimer's disease with cholinesterase inhibitors is a matter of controversy. We evaluated the effects of prolonged treatment with eptastigmine in 176 patients with mild to moderate Alzheimer's disease participating in the open-label extension phase of a 25-week double-blind, placebo-controlled trial of eptastigmine. The effects of eptastigmine on cognition and daily functioning were evaluated with the cognitive portion of the Alzheimer's Disease Assessment Scale (ADAS-Cog) and the Instrumental Activities of Daily Living (IADL) scale, respectively. Safety was monitored by physical examination, laboratory tests, vital functions and electrocardiogram measurements and by the assessment of adverse events. One hundred and fifty-three patients (87%) completed 1 year of treatment, 77 patients (44%) 18 months and 33 patients (19%) 2 years of treatment. Patients treated for 2 years showed an improvement of mean ADAS-Cog scores compared to baseline for 31 weeks and mean IADL scores remained close to baseline for 25 weeks. Cognitive and functional scores then worsened as expected in this progressive disease. After 2 years, patients deteriorated compared to baseline by 13.4 points on the ADAS-Cog and 6.1 points on IADL. Historical untreated controls with identical disease severity are expected to have an annual worsening of approximately 10.9 points on ADAS-Cog and 4.9 points on IADL. Thus patients treated with eptastigmine for 2 years had a benefit of 8.5 points on ADAS-Cog and 3.8 points on IADL. These benefits translate to about 9 months difference between eptastigmine-treated patients and untreated historical patients. The drug was generally well tolerated with 14 patients (7.9%) withdrawing due to adverse events. Adverse events, not necessarily drug-related, were recorded in 66 patients (37.5%) and were transient and generally mild in severity. This study indicates that prolonged treatment with eptastigmine is safe and produced a clinically long-term benefit in patients with Alzheimer's disease.

A 25-week placebo-controlled study of eptastigmine in patients with Alzheimer disease

The efficacy and safety of eptastigmine in patients with probable Alzheimer disease was evaluated in a double-blind, placebo-controlled, parallel group study. Patients with mild to moderate dementia were randomly assigned to placebo, eptastigmine 10 mg three times a day (t.i.d.), or eptastigmine 15 mg t.i.d. over 25 weeks. The Alzheimer Disease Assessment Cognitive Subscale (ADAS-Cog) and the Clinician's Interview-Based Impression of Change Plus (CIBIC-Plus) were the primary outcome measures for efficacy. Twenty-six centers recruited 320 patients: 106 on placebo, 105 on eptastigmine 10 mg t.i.d., and 109 on eptastigmine 15 mg t.i.d. Six patients on placebo (6%), 18 patients on eptastigmine 10 mg t.i.d. (17%), and 10 patients on eptastigmine 15 mg t.i.d. (9%) discontinued study treatment. The intent-to-treat analysis on 315 patients showed a statistically significant (p=0.047) difference of 2.0 points on ADAS-Cog between the placebo and the eptastigmine 15 mg t.i.d. group at the end of treatment. Patients in the 10 mg t.i.d. group performed better than did placebo-treated patients on the Spontaneous Behavior Interview (SBI) total scores (p=0.015) and on the Activities of Daily Living (ADL, p=0.043) and Behavioral Problems (BP, p=0.028) subscales. The differences in favor of the eptastigmine groups on the CIBIC-Plus did not reach statistical significance. In a post hoc subgroup analysis by staging, the effect size of eptastigmine was found to be greater in the most severely impaired patients (Global Deterioration Scale rating of 4 and 5 at screening) reaching statistical significance in both ADAS-Cog (p=0.007) and CIBIC-Plus (p=0.038). In this patient subgroup (n=222), there was also a significant effect of eptastigmine on SBI (p=0.019). The drug was generally well tolerated, with 8% of patients withdrawing due to adverse events versus 5% on placebo. Adverse events were recorded in 35 patients (33%) on placebo compared with 41 (39%) on eptastigmine 10 mg t.i.d. and 38 (35%) on eptastigmine 15 mg t.i.d. This study shows that eptastigmine doses up to 15 mg t.i.d. for 25 weeks are well tolerated. The drug positively affects cognitive performance of Alzheimer patients. This effect appears greater in more severely impaired patients and also impacts on their behavioral performance.

Effects of lead exposure on licking and yawning behaviour in rats

In the present study, effects of lead exposure on licking and yawning behaviour have been studied. The dopaminergic receptor agonist, apomorphine (0.15, 0.25 and 0.5 mg/kg), induced dose-dependent licking in rats. The maximum response was obtained with 0.5 mg/kg of the apomorphine. Lead acetate (0.05%) exposure significantly increased apomorphine-induced licking. Yawning induced by the D2 dopaminergic agonist, bromocriptine (2, 3, 4, 8 mg/kg), and the cholinergic drug, physostigmine (0.1 or 0.3 mg/kg), was significantly decreased by lead acetate (0.05%) exposure. It may be concluded that the behaviour induced by dopaminergic or cholinergic agents can be affected by lead subchronic exposure.

Maximum tolerated dose and pharmacodynamics of eptastigmine in elderly healthy volunteers

Eptastigmine is a new acetylcholinesterase (AChE) inhibitor currently under development for the symptomatic treatment of Alzheimer disease. This study was conducted to establish the maximum tolerated dose and the pharmacodynamics of eptastigmine in nine healthy elderly volunteers. Subjects received single oral doses of 8 mg, 20 mg, 32 mg, and 40 mg eptastigmine and placebo according to a double-blind, randomized, rising-dose, five-way crossover design. Adverse events, blood pressure, heart rate, body temperature, forced expiratory volume, salivary flow, and pupilar activity were closely monitored during treatment. Pharmacodynamic activity of eptastigmine was evaluated with an assay of AChE activity in red blood cells. Eptastigmine doses of 8 mg, 20 mg, and 32 mg were well tolerated. Two of four subjects receiving the 40-mg dose developed profound AChE inhibition (58-59%) and reported severe adverse events (nausea, vomiting, syncope, and bradycardia), precluding further administration in the remaining subjects. Eptastigmine administration produced a weak effect on supine heart rate, body temperature, and pupil diameter. There were no effects on blood pressure, forced expiratory volume, salivary flow, and near point of focus. Acetylcholinesterase activity was inhibited in a dose-related fashion according to a sigmoidal (logistic) function. The mean (+/- SEM) maximum inhibition of AChE activity (Imax) was 14.5+/-3.3%, 20.4+/-2.3%, 28.7+/-2.9%, 45.2+/-1.3% and 53.6+/-2.9% after placebo, 8 mg, 20 mg, 32 mg, and 40 mg of eptastigmine, respectively. The theoretical maximum response (Emax) was 72.9%, and the dose that produced half of the maximum response (ED50) was 29.5 mg. At 24 hours, residual AChE inhibition ranged from 9% to 15%, with a half-life of recovery of the enzyme of approximately 10 hours. The maximum tolerated dose of eptastigmine after single-dose oral administration in healthy elderly subjects is 32 mg. Single oral doses of eptastigmine produce sustained, dose-related inhibition of AChE activity. Adverse events are related to the degree of AChE inhibition.

Effect of food on the absorption of eptastigmine

OBJECTIVE

The aim of the study was to evaluate the effects of food on the rate and extent of eptastigmine absorption in healthy volunteers.

METHODS

The study was carried out according to a double-blind, randomized, placebo-controlled, three-way cross-over design. On three separate occasions, six young subjects received 30 mg eptastigmine after a 12-h overnight fast (reference treatment), 30 mg eptastigmine 15 min after a standard breakfast (test treatment) and placebo 15 min after a standard breakfast (control treatment). Acetylcholinesterase activity in red blood cells was assayed 24 h after drug administration as a biological marker of eptastigmine plasma concentrations.

RESULTS

Mean maximum acetylcholinesterase inhibition (Imax) was 39.9% after eptastigmine without food and 33.1% after eptastigmine with food. Maximum inhibitions occurred at 4.75 h and 4.88 h after eptastigmine without and with food, respectively. Areas under the curve of acetylcholinesterase per cent inhibition from 0 to 8 h after drug administration (AUC0-8) were 198% h after eptastigmine without food and 124% h after eptastigmine with food. Ninety per cent confidence intervals of test/reference ratios for AUC0-8 and Imax exceeded the 0.80 to 1.20 limits, thus indicating that the two eptastigmine treatments cannot be considered bioequivalent. Mild and transient adverse events were recorded in three subjects receiving eptastigmine without food, one subject receiving eptastigmine with food and one subject receiving placebo.

CONCLUSIONS

The ingestion of food significantly reduces the bioavailability of eptastigmine estimated by the assay of red blood cell acetylcholinesterase activity.

Subchronic physostigmine pretreatment in guinea pigs: effective against soman and without side effects

The behavioral and neurophysiological effects of the subchronically administered cholinesterase-inhibitor physostigmine (PHY) (0.025 mg/kg/h) either with or without the muscarinergic antagonist scopolamine (SCO) (0.018 mg/kg/h) were determined in guinea pigs. In contrast to a single injection of PHY, subchronic application by osmotic minipumps of PHY, even without SCO, caused no behavioral or neurophysiological side effects. Also, the efficacy of such a pretreatment in counteracting soman-induced lethality and apparent symptoms of intoxication were determined. After subchronically administered PHY or PHY + SCO, the treated animals were protected against a 3 x LD50 dose of soman.

Donepezil medicated memory improvement in traumatic brain injury during post acute rehabilitation

Memory dysfunction is a recognized and difficult to treat complication of traumatic brain injury (TBI). Since medial-temporal lobe injury is a frequent contributor to memory dysfunction in TBI, it is likely that an acetylcholine deficit contributes to memory dysfunction in this population. Recently, Donepezil, an acetylcholine-esterase inhibitor which has demonstrated a high selectivity for neural Ach-esterase (with minimal side effects), was approved for use in dementia in Alzheimer's patients. Due to its promising results in Alzheimer's patients, and reports in the literature describing the use of physostigmine (an anti-cholinesterase with significant cardiovascular and autonomic side effects) to treat memory deficits in closed head injury, we decided to begin a trial of Donepezil in two patients with TBI who were experiencing long term static memory dysfunction refractory to conventional treatment. Both patients were admitted to our facility for physical and cognitive rehabilitation, and were started on a trial of Donepezil. Modified memory tests and subjective observations by both family and staff pointed to an improvement in memory within three weeks of starting Donepezil. Should these initial results be supported in larger trials, Donepezil may prove to be a valuable tool for the treatment of memory dysfunction in TBI.

Physostigmine increases aqueous humor production in human eyes

PURPOSE

To investigate if part of the progressive reduction of intraocular pressure (IOP), seen when physostigmine is applied on alternate hours, is due to a reduced aqueous flow.

METHODS

In a randomized, open study, one drop of physostigmine salicylate, 8 mg/ml, was instilled at 7 AM in one randomly assigned eye in each of twenty healthy volunteers. Instillations were repeated on alternate hours throughout the day. Each subject's untreated eye served as control. Fluorophotometry of the anterior segment was performed hourly between 7 Am and 8 PM and aqueous flow was calculated. Subsequently, the subjects underwent tomography and tonometry. The change in anterior chamber depth and volume induced by physostigmine was assessed separately.

RESULTS

The mean aqueous flow during the day was 25-28% higher in the physostigmine-treated eye than in the control eye. The difference was statistically significant from 9 AM (p < 0.05-p < 0.001). Each dose caused a further increase. The mean outflow facility increased by 0.14 microliters/min/mm Hg with 95% confidence interval (CI) 0.09-0.18. Although the increase in outflow facility was small, there was a marked reduction of IOP with a mean difference between treated and untreated eye of 3.2 mm Hg (95% CI: 2.3-4.0).

CONCLUSIONS

Repeated administrations of physostigmine increase the aqueous flow and outflow facility. The combined effect is a marked reduction of IOP.

Physostigmine increases the dose of propofol required to induce anaesthesia

PURPOSE

This prospective, randomized, double-blind study was performed to determine the effect of administration of physostigmine on the dose of propofol required to produce loss of consciousness.

METHODS

Forty female unpremedicated patients were assigned in a random blind design to receive either 2 mg physostigmine or equal volume of normal saline i.v. five minutes before induction of anaesthesia with propofol. All patients received general anaesthesia for breast surgery. Propofol was infused at a constant rate of 200 ml.hr-1 while patients were breathing oxygen 100% via a face mask. In each patient the dose of propofol required to produce loss of the ability to grasp a 20 ml syringe was recorded as the end-point of loss of consciousness. At this point the protocol was terminated and, after intubation of the trachea, anaesthesia was maintained with a nitrous oxide-isoflurane or sevoflurane mixture in oxygen, increments of an opioid and a muscle relaxant. Doses of anaesthetic drugs and duration of anaesthesia varied and depended on the type of breast surgery, determined by frozen section.

RESULTS

The mean +/- SD dose of propofol required to produce loss of consciousness was 2.4 +/- 0.6 mg.kg-1 and 2.0 +/- 0.4 mg.kg-1 in the physostigmine and in the normal saline groups respectively (P = 0.014).

CONCLUSION

Physostigmine pretreatment increases the dose of propofol required to produce loss of consciousness.

Assessment of motor and process skills as a measure of IADL functioning in pharmacologic studies of people with Alzheimer's disease: a pilot study

The purpose of this pilot study was to evaluate the usefulness of the Assessment of Motor and Process Skills (AMPS) as an outcome measure of instrumental activities of daily living (IADL) in pharmacologic studies of people with Alzheimer's disease. The AMPS simultaneously measures motor and process skills and their effect on the ability of the person to perform familiar IADL tasks. We administered the AMPS to 11 Alzheimer inpatients in a 3 1/2-month, double-blind, placebo-controlled, crossover study of fluoxetine and selegiline administered as single agents and in combination with physostigmine. Results indicated that there was a significant difference in IADL ability among study conditions for process skills, but not for motor skills, thereby suggesting that the AMPS is useful as a sensitive outcome measure of IADL ability in drug trials with this population.

Clinical applications of commonly used contemporary antidotes. A US perspective

Poisonings are a common problem. In 1995, over 2 million exposures were reported to American poison information centres alone. The majority of poisoning exposures can be treated without major therapeutic intervention. If therapy is indicated, it is usually in the form of gastrointestinal decontamination with activated charcoal, to prevent absorption of the toxin and the subsequent toxicity that may occur. In a limited number of cases, more aggressive life-support measures may be necessary to treat the adverse effects of poisons. Occasionally, that intervention may include the use of pharmacological antagonists, more commonly referred to as antidotes. According to the American Association of Poison Control Centers, the most commonly used antidotes are acetylcysteine, naloxone, atropine, deferoxamine (desferrioxamine) and antivenins. Overall, 17 antidotes account for 99% of all antidote use and those agents are reviewed in this article. With the exception of naloxone, most antidotes have pharmacological effects that are independent of their inherent antidotal properties. Therefore, antidotes should be used judiciously because their pharmacological properties may exacerbate pre-existing toxicity and only in rare circumstances are they used prophylactically. Some antidotes, such as digoxin-specific antigen binding fragments (digoxin immune Fab), are very expensive, and both the risk: benefit ratio and the associated cost should be considered before the antidote is administered. The principle aims are to "treat the patient, not the poison' and to do no harm to the patient. Antidotes should be used only when they are indicated and may help a patient.

A multicenter double-blind study of controlled-release physostigmine for the treatment of symptoms secondary to Alzheimer's disease. Physostigmine Study Group

OBJECTIVE

A multicenter trial to evaluate the efficacy of controlled-release physostigmine salicylate, a cholinesterase inhibitor, was conducted in 1,111 mild-to-moderate Alzheimer's disease (AD) subjects.

DESIGN

During dose titration, subjects received 18, 24, or 30 mg of physostigmine or placebo daily. After a 2-week washout period, 366 subjects with putative improvement were randomized to receive either placebo or their best dose of physostigmine in a 6-week double-blind trial. Nonresponding patients (439) were randomized to receive in a separate double-blind trial either placebo or their highest tolerated dose of physostigmine. The primary efficacy measures included the cognitive subscale of the Alzheimer Disease Assessment Scale (ADAS) and a Clinical Global Impression of Change (CGIC). Secondary measures included the Mini-Mental State Examination and two activities-of-daily-living scales.

RESULTS

At the end of the 6-week double-blind phase, physostigmine-treated patients scored 1.75 points higher than placebo-treated patients on the ADAS (p = 0.003) and 0.26 points higher on the CGIC (p = 0.012) in the intent-to-treat analysis. There was no significant improvement on the secondary outcome measures. Patients failing to respond to physostigmine during the dose titration phase failed to respond on any of the outcome measures during the double-blind period of re-exposure. Common adverse events included nausea, vomiting, diarrhea, and anorexia. There were no significant changes in liver function tests.

CONCLUSION

This study demonstrated statistically significant differences between physostigmine and placebo on both a performance-based cognitive functioning instrument and a clinician's global evaluation. The magnitude of the effect size was small and occurred only in the subset of patients who responded in the initial dose titration study period. Nevertheless, the results suggest that in a subset of patients, physostigmine can induce a degree of cognitive improvement over 6 weeks of treatment.

Relationship between pharmacodynamic activity and cognitive effects of eptastigmine in patients with Alzheimer's disease. Eptastigmine Study Group

OBJECTIVE

To assess the safety, tolerability, pharmacodynamics, and preliminary efficacy of eptastigmine, a new long-acting cholinesterase inhibitor, in patients with probable Alzheimer's disease.

METHODS

This was a double-blind, randomized, placebo-controlled, unbalanced parallel-group study. One-hundred and three patients (83 in the eptastigmine group and 20 in the placebo group) were recruited by 10 centers. Patients received 20 mg eptastigmine or placebo for 4 weeks with twice-a-day or three-times-a-day regimens, depending on body weight (< or = 65 kg or > 65 kg, respectively). Patient performance on the Logical Memory Test, Semantic Word Fluency Test, Trail Making Test, Index of Independence in Activities of Daily Living, Instrumental Activities of Daily Living Scales (IADL), and the Physician and Caregiver Clinical Global Impression of Change (CGIC) was assessed at baseline and at the end of treatment.

RESULTS

Nine patients, all from the eptastigmine group, did not complete treatment because of uncooperativeness (n = 3), adverse events (n = 3), protocol violations (n = 2), and clinical decline (n = 1). Twenty-five patients receiving eptastigmine (34%) reported adverse events mainly of the cholinergic type. Cholinergic side effects were generally associated with peak red blood cell cholinesterase inhibition exceeding 50% after the first dose, or 70% at steady state. At steady state, average daily acetylcholinesterase inhibition ranged from 13% to 54%. Overall, 34% of patients receiving eptastigmine versus 0% receiving placebo (p = 0.006) improved on the Physician CGIC. This percentage increased to 46% in the subgroup of patients with average daily acetylcholinesterase inhibition ranging from 30% to 35%. Patient performance on the IADL also improved significantly compared with the placebo group (p = 0.019). In the eptastigmine group, performances on all tests and scales improved with an inverted U-shaped relation to average daily acetylcholinesterase inhibition.

CONCLUSIONS

This study shows that doses of 40 to 60 mg per day of eptastigmine are relatively safe and well tolerated and that moderate acetylcholinesterase inhibition is associated with maximal cognitive efficacy.

[Physostigmine in treatment of cerebellar ataxia]

Cerebellar ataxias are still a challenging problem for neurologists, and to this day there exists no medical, physiotherapeutic, psychot-erapeutic or surgical therapy which constantly leads to a reduction of ataxic symptoms. In the pathophysiology of cerebellar ataxia a cholinergic defect has often been described. In a double-blind, cross-over study with 14 patients with cerebellar ataxia and an open follow-up, long-term study with 21 patients, the clinical effects of physostigmine capsules in doses up to 10 mg per day were studied. Moreover, a transdermal application (physostigmine patch) was developed, achieving constant physostigmine plasma levels for 24 h. Of 14 patients treated with physostigmine during the double-blind, cross-over study, nine could correctly distinguish between verum and placebo. They all showed small but constant improvements, clearly experienced by the patients. With the physostigmine patch, 12 of 14 patients improved. Thirteen of 14 patients decided to take part in open follow-up studies with physostigmine, and most of them preferred the physostigmine patch as long-term medication. To date, 21 patients with cerebellar ataxia have been treated with physostigmine. As far as we can judge at the end of a treatment period of at least 2 years, the progression of the disease could be stopped in 17 of 21 patients. These patients reported small but constant effects, and none wants to live without the physostigmine patch.

L-deprenyl and physostigmine for the treatment of Alzheimer's disease

The present study evaluated the safety of and obtained preliminary data on the cognitive effects of L-deprenyl and physostigmine in patients with Alzheimer's Disease. Seventeen outpatients with Alzheimer's Disease participated in a double-blind crossover study in which they received 4 weeks of L-deprenyl at a dose of 10 mg p.o., q.d., and 4 weeks of placebo in random order. During both the L-deprenyl and placebo periods, patients received cognitive assessments during physostigmine (0.5 mg) and placebo infusions separated by 2 days. The cognitive effects of these agents alone and in combination were measured with digit span, verbal fluency, list learning, praxis, delayed recall, and delayed recognition tasks. Fifteen patients completed the study. The two drugs, used alone or in combination, were safe and well tolerated. Analyses of variance demonstrated that neither physostigmine nor L-deprenyl, whether given alone or in combination, significantly improved cognition, when compared with the double placebo condition.

Oral physostigmine in Alzheimer's disease: effects on norepinephrine and vasopressin in cerebrospinal fluid and plasma

Physostigmine is a cholinesterase inhibitor which enhances central and peripheral cholinergic activity. In this study, we explored in persons with Alzheimer's disease (AD) the effects of an acute dose of physostigmine in patients receiving chronic physostigmine treatment on the activity of the cholinergically regulated noradrenergic and arginine vasopressin (AVP) systems. Specifically, we estimated the effects of sustained release oral physostigmine on central and peripheral noradrenergic and AVP systems by measuring norepinephrine (NE) and AVP in cerebrospinal fluid (CSF) and plasma. Lumbar punctures were performed in both physostigmine and no drug treatment conditions. In some subjects the effects of physostigmine on the plasma AVP response to the osmolar stimulus of a hypertonic saline infusion also were measured. NE concentrations in both CSF and plasma were significantly lower in the physostigmine than in the no drug condition. AVP concentrations did not differ between conditions in either compartment, nor did physostigmine affect the AVP response to hypertonic saline. Physostigmine appears to decrease both central and peripheral noradrenergic activity in AD.

[Antagonists in anesthesia]

In modern anaesthesia various antagonists are used. They provide efficient tools to facilitate better control of pharmacological effects and side effects of drugs routinely used in anaesthesia. Naloxone is a competitive antagonist of opioids without any intrinsic activity. It counteracts respiratory depression, pruritus, sedation and analgesia caused by opioids. It is fast-acting with a duration of action of 45 to 90 min. Several investigators have reported severe side effects of naloxone including hypertension, tachyarrhythmias, left heart failure and cardiac arrest, and hence the use of naloxone must be carefully considered in every single patient. Flumazenil is a competitive antagonist of benzodiazepines. It is a remarkably safe drug and very effective to terminate all benzodiazepine effects in anaesthesia and intensive-care patients. Serious complications caused by flumazenil have been reported in patients receiving benzodiazepines in the treatment of seizure disorders and in patients with mixed intoxications. Neostigmine is one of several antagonists of neuromuscular blocking agents. Its side effects include bradycardia, increased bronchial secretions and increased peristalsis. Indication depends on the results of neuromuscular monitoring. Physostigmine is an unspecific antagonist of the central anticholinergic syndrome, an acute psychosis that may be caused by numerous drugs used in anaesthesia. Generally, antagonists should be carefully titrated. In emergency medicine the use of these antagonists is not recommended; the primary goal is to restore vital functions.

Scientific and ethical concerns in clinical trials in Alzheimer's patients: the bridging study

This paper reviews the scientific and ethical issues surrounding the conduct of bridging studies in patients with Alzheimer's disease (AD). Bridging studies, so called because they facilitate the transition from phase I to phase II development, are late phase I safety/tolerance studies which determine the maximum tolerated dose (MTD) in patients before initiating phase II efficacy studies. Determining the MTD in patients is important because we have found that AD patients appear to respond to cholinergic compounds differently from normal volunteers, reaching a different MTD. Preliminary evidence of dose-related efficacy with two cholinergic compounds lends support to our contention that determination of the highest tolerated dose maximizes the potential to detect efficacy. We will review the early clinical development of several cholinergic compounds and make recommendations for the design and conduct of bridging studies based on our experience. A fixed-dose panel design with dosages based on the MTD determined in normal volunteers is recommended. In order to minimize risk to the patients, ensuring that scientific benefits outweigh the risks, a bridging study must be supported by detailed preclinical toxicology, by a clinical research unit that is prepared to handle unexpected contingencies, and by the oversight of a competent, multi-disciplinary review board. Patients should be in good physical health (excluding AD), and a comprehensive informed consent procedure must be instituted. Carefully planned and well run bridging studies represent a scientifically and ethically sound approach to drug development in the Alzheimer's population.

Protracted post-traumatic confusional state treated with physostigmine

A case study is presented of confusion in a head-injured man, lasting for more than 2 years, when intermittent treatment with physostigmine resulted in progressive improvement in both confusion and usable cognitive functions. Aetiological mechanisms and implications for treatment plans are discussed.