Diphenhydramine-Induced Antimuscarinic Delirium Treated with Physostigmine and Transdermal Rivastigmine.

INTRODUCTION: Recurrent physostigmine shortages present a challenge to healthcare providers treating antimuscarinic delirium. Other centrally acting acetylcholinesterase inhibitors such as rivastigmine may represent a therapeutic alternative or adjunct during physostigmine shortage; however, previous reports of use have not documented serum antimuscarinic toxin concentrations, limiting evaluation of effectiveness. Combination therapy with physostigmine and rivastigmine has not been described. In this report, the authors present a case of diphenhydramine-induced antimuscarinic delirium with elevated diphenhydramine serum concentrations treated with physostigmine and transdermal rivastigmine without observed adverse effect. CASE REPORT: A 48-year-old female presented to an emergency department after ingesting 3.75 g (41.2 mg/kg) of diphenhydramine. She had antimuscarinic delirium with a presenting serum diphenhydramine concentration of 1500 ng/mL (therapeutic range, 25-112 ng/mL) and required two doses of physostigmine to avert intubation prior to intensive care unit (ICU) admission. At hospital hour 22, in the ICU, antimuscarinic delirium persisted but no further physostigmine was available due to hospital shortage. Therefore, a 9.5-mg transdermal rivastigmine patch was applied. By hospital hour 24, her delirium had resolved. A serum diphenhydramine concentration at hospital hour 25 was elevated at 760 ng/mL. Transdermal rivastigmine was discontinued at hospital hour 48 without recurrent delirium. Despite persistent normal mental status after rivastigmine discontinuation, the patient had a dry mouth, difficulty urinating, and mydriasis until hospital day 5. She never developed muscarinic toxicity. DISCUSSION: Transdermal rivastigmine may be a useful treatment alternative or adjunct during physostigmine shortage for antimuscarinic delirium and has a long duration of action without aspiration risk. Muscarinic toxicity was not observed.

Physostigmine should be used more readily for antimuscarinic toxicity: PRO.

Physostigmine is the preferred treatment for antimuscarinic toxicity. Its use has a clear biological rationale and is supported by extensive clinical use which demonstrated effectiveness and safety.

[Update - intoxications in critical care medicine]. / Update ­ Intoxikationen in der Intensivmedizin.

While monitoring and symptomatic care is sufficient for most intoxicated patients, some develop life threatening symptoms. We present recent changes in the recommendations of the treatment in patients with calcium channel blocker, beta blocker and high dose paracetamol intoxications. Additionally, new insights in the efficacy and safety of the use of physostigmine in anticholinergic patients and beta blockers in cocaine intoxication are discussed as well as the specific considerations in the resuscitation of intoxicated patients.

Adverse Effects of Physostigmine.

INTRODUCTION: Physostigmine is a tertiary amine carbamate acetylcholinesterase inhibitor. Its ability to cross the blood-brain barrier makes it an effective antidote to reverse anticholinergic delirium. Physostigmine is underutilized following the publication of patients with sudden cardiac arrest after physostigmine administration in patients with tricyclic antidepressant (TCA) overdoses. We completed a narrative literature review to identify reported adverse effects associated with physostigmine administration. DISCUSSION: One hundred sixty-one articles and a total of 2299 patients were included. Adverse effects occurred in 415 (18.1%) patients. Hypersalivation (206; 9.0%) and nausea and vomiting (96; 4.2%) were the most common adverse effects. Fifteen (0.61%) patients had seizures, all of which were self-limited or treated successfully without complication. Symptomatic bradycardia occurred in 8 (0.35%) patients including 3 patients with bradyasystolic arrests. Ventricular fibrillation occurred in one (0.04%) patient with underlying coronary artery disease. Of the 394 patients with TCA overdose, adverse effects were described in 14 (3.6%). Adverse effects occurred in 7.7% of patients treated with an overdose of an anticholinergic agent compared with 20.6% of patients with non-anticholinergic agents. Five (0.22%) fatalities were identified. CONCLUSIONS: In conclusion, significant adverse effects associated with the use of physostigmine were infrequently reported. Seizures were self-limited or resolved with benzodiazepines, and all patients recovered neurologically intact. Physostigmine should be avoided in patients with QRS prolongation on EKG, and caution should be used in patients with a history of coronary artery disease and overdoses with QRS prolonging medications. Based upon our review, physostigmine is a safe antidote to treat anticholinergic overdose.

Physostigmine is superior to non-antidote therapy in the management of antimuscarinic delirium: a prospective study from a regional poison center.

CONTEXT: Poison centers (PCs) frequently manage patients with antimuscarinic delirium. However, controversy surrounds the antidotal use of physostigmine for its treatment. The aim of this study was to prospectively investigate physostigmine versus non-antidote therapy for the management of antimuscarinic delirium in a single regional PC. METHODS: This was a prospective observational analysis of patients diagnosed with antimuscarinic delirium and treated in consultation with a regional PC. Certified Specialists in Poison Information (CSPIs) use a clinical guideline to recommend the use of physostigmine. Using a previously derived altered mental status score, we quantified the rate of delirium improvement with physostigmine compared to non-antidote therapy two hours after initial patient identification. We also recorded adverse events (defined a priori as bradycardia, vomiting, seizures) and resource utilization (intubation and physical restraint). RESULTS: We identified 245 patients and included 154 in the analysis. The most common exposure classes were antihistamines (68%), analgesics (19%), and antipsychotics (19%). CSPIs recommended physostigmine in 81% (125) of cases and the treatment team administered it in 37% (57) of these. We observed delirium control in 79% of patients who received physostigmine versus 36% of those who did not. The odds of delirium control were six times greater for patients receiving physostigmine than for patients treated with non-antidote therapy (OR 6.6). Adverse events were rare and did not differ significantly between the groups. Physostigmine was not associated with changes in the incidence of intubation or restraint. CONCLUSIONS: This study provides further evidence of both the safety and efficacy of physostigmine in the treatment of antimuscarinic delirium.

Safety and effectiveness of physostigmine: a 10-year retrospective review.

BACKGROUND: Physostigmine has long been recognized as an antidote to reverse anticholinergic delirium. However, its effectiveness, safety profile, and dosing have been disputed. OBJECTIVES: To describe effectiveness, adverse events, and dosing associated with the use of physostigmine to reverse anticholinergic delirium. METHODS: A retrospective cohort study of hospitalized patients reported to a regional poison center system between 2003 and 2012 who received physostigmine to reverse an anticholinergic toxidrome. Data extraction of a priori defined variables were recorded with concurrence of investigators. The cases were stratified by the primary ingestant as the presumed causative agent and associations for response were performed using odds ratios (ORs), 95% confidence intervals (CI's), and p values. RESULTS: Of the 1422 cases identified, 191 met the inclusion criteria. Patients exposed to non-diphenhydramine antihistamines (n = 14), antipsychotics (n = 4), and tricyclic antidepressants (n = 3) had 100% response to physostigmine, whereas anticholinergic plants (n = 46/67; 68.7%, OR: 0.70; CI: 0.36-1.35), diphenhydramine (n = 43/56; 64.2%, OR: 1.30; CI: 0.63-2.68), and combination products (n = 8/10; 80%, OR: 1.48; CI: 0.30-7.24) had partial response rates. Of the included patients, 142 (74.3%) were treated with physostigmine alone, and 16 (8.4%) of these patients were discharged directly from the emergency department (ED). DISCUSSION: Most patients, 182 (95.3%), had no documented adverse effects. Four patients (2.1%) experienced emesis, two experienced QTc prolongation (1.0%), and two experienced seizures (1.0%). There was a single fatality 6 h after physostigmine administration. Average initial total doses of physostigmine ranged from 1.0 to 1.75 mg. Most patients were admitted to the ICU (n = 110; 57.6%), however, 36 (18.8%) patients were discharged directly from the ED. CONCLUSIONS: In this retrospective cohort study, physostigmine administration to reverse anticholinergic delirium had a good safety profile, and often improved or resolved anticholinergic delirium when administered in doses less than 2 mg.

Adjunctive use of physostigmine salicylate (Anticholium®) in perioperative sepsis and septic shock: study protocol for a randomized, double-blind, placebo-controlled, monocentric trial (Anticholium® per Se).

BACKGROUND: Severe sepsis and septic shock remain a major challenge, even in modern intensive care. In Germany, about 68,000 patients die annually because of septic diseases, characterized by a complex systemic inflammatory response. Causal treatment of the underlying infection is essential for successful management of sepsis, but the course can be positively influenced by supportive and adjuvant measures. The cholinergic anti-inflammatory pathway (CAP) represents a new approach to adjunctive therapy of septic diseases and can be pharmacologically activated by the acetylcholinesterase inhibitor physostigmine (Anticholium®). Promising effects can be found in several in vitro and in vivo models of sepsis, such as a reduction in pro-inflammatory cytokines and improved survival. METHODS: Anticholium® per Se is a randomized, double-blind, placebo-controlled, monocentric trial to assess whether the CAP can be transferred from bench to bedside. In this pilot study, 20 patients with perioperative sepsis and septic shock as a result of intra-abdominal infection are enrolled. According to randomization, participants are treated with physostigmine salicylate (verum group) or 0.9% sodium chloride (placebo group) for up to 5 days. The mean Sequential Organ Failure Assessment (SOFA) score during treatment and subsequent intensive care of up to 14 days is used as surrogate outcome (primary endpoint). Secondary outcome measures include 30- and 90-day mortality. An embedded pharmacokinetics and pharmacodynamics study investigates plasma concentrations of physostigmine and its metabolite eseroline. Further analyses will contribute to our understanding of the role of various cytokines in the pathophysiology of human sepsis. A computer-generated list is used for block randomization. DISCUSSION: This randomized, controlled, monocentric trial investigates for the first time the adjunctive use of physostigmine (Anticholium®) in patients with perioperative sepsis and septic shock and may be a pivotal step toward the clinical use in this indication. TRIAL REGISTRATION: EudraCT Number: 2012-001650-26 (entered 14 August 2012), ClinicalTrials.gov identifier: NCT03013322 (registered on 1 Jan 2017).

Pharmacological management of anticholinergic delirium - theory, evidence and practice.

The spectrum of anticholinergic delirium is a common complication following drug overdose. Patients with severe toxicity can have significant distress and behavioural problems that often require pharmacological management. Cholinesterase inhibitors, such as physostigmine, are effective but widespread use has been limited by concerns about safety, optimal dosing and variable supply. Case series support efficacy in reversal of anticholinergic delirium. However doses vary widely and higher doses commonly lead to cholinergic toxicity. Seizures are reported in up to 2.5% of patients and occasional cardiotoxic effects are also recorded. This article reviews the serendipitous path whereby physostigmine evolved into the preferred anticholinesterase antidote largely without any research to indicate the optimal dosing strategy. Adverse events observed in case series should be considered in the context of pharmacokinetic/pharmacodynamic studies of physostigmine which suggest a much longer latency before the maximal increase in brain acetylcholine than had been previously assumed. This would favour protocols that use lower doses and longer re-dosing intervals. We propose based on the evidence reviewed that the use of cholinesterase inhibitors should be considered in anticholinergic delirium that has not responded to non-pharmacological delirium management. The optimal risk/benefit would be with a titrated dose of 0.5 to 1 mg physostigmine (0.01-0.02 mg kg(-1) in children) with a minimum delay of 10-15 min before re-dosing. Slower onset and longer acting agents such as rivastigmine would also be logical but more research is needed to guide the appropriate dose in this setting.

Use of a physostigmine continuous infusion for the treatment of severe and recurrent antimuscarinic toxicity in a mixed drug overdose.

INTRODUCTION: Physostigmine was once a widely used antidote for the treatment of antimuscarinic toxicity. However, reports describing the association of physostigmine with asystole and seizures in severe tricyclic antidepressant poisoning resulted in a decrease in use. Recent literature has demonstrated that physostigmine is a safe and effective antidote for the treatment of antimuscarinic toxicity. There are only two previously published articles regarding the use of physostigmine administered as a continuous intravenous infusion for persistent antimuscarinic toxicity. We present a case of physostigmine continuous infusion for the treatment of antimuscarinic symptoms in a polydrug overdose due to the ingestion of diphenhydramine along with bupropion, citalopram, acetaminophen, and naproxen. CASE PRESENTATION: A 13-year-old female presented with hyperthermia, myoclonus and rigidity, hallucinations, severe agitation, and antimuscarinic toxicity including inability to sweat after a polydrug overdose. Several doses of lorazepam were administered followed by physostigmine which produced resolution of hallucinations and attenuation of the antimuscarinic symptoms including perspiration, temperature improvement, and decreased agitation. After periods of improvement and recurrence of antimuscarinic effects, a continuous infusion of physostigmine was administered at 2 mg/h and continued for almost 8 h to maintain attenuation of symptoms. GABAergic agents including lorazepam and phenobarbital were used later in the hospital course for presumed symptoms of serotonergic and adrenergic toxicity after resolution of antimuscarinic effects. The patient did not experience any adverse effects of physostigmine administration. DISCUSSION: Physostigmine administered as a continuous infusion may be a reasonable treatment option for severe and recurrent symptoms related to antimuscarinic toxicity.

Posiphen as a candidate drug to lower CSF amyloid precursor protein, amyloid-ß peptide and τ levels: target engagement, tolerability and pharmacokinetics in humans.

AIM: A first in human study to evaluate tolerability and pharmacokinetics followed by an early proof of mechanism (POM) study to determine whether the small orally, available molecule, Posiphen tartrate (Posiphen), lowers secreted (s) amyloid-ß precursor protein (APP) α and -ß, amyloid-ß peptide (Aß), tau (τ) and inflammatory markers in CSF of patients with mild cognitive impairment (MCI). STUDY DESIGN: Posiphen single and multiple ascending dose phase 1 randomised, double blind, placebo-controlled safety, tolerance, pharmacokinetic studies were undertaken in a total of 120 healthy volunteers to define a dose that was then used in a small non-randomised study of five MCI subjects, used as their own controls, to define target engagement. MAIN OUTCOME MEASURES: Pharmacodynamic: sAPPα, sAPPß, Aß(42), τ (total (t) and phosphorylated (p)) and inflammatory marker levels were time-dependently measured over 12 h and compared prior to and following 10 days of oral Posiphen treatment in four MCI subjects who completed the study. Pharmacokinetic: plasma and CSF drug and primary metabolite concentrations with estimated brain levels extrapolated from steady-state drug administration in rats. RESULTS: Posiphen proved well tolerated and significantly lowered CSF levels of sAPPα, sAPPß, t-τ, p-τ and specific inflammatory markers, and demonstrated a trend to lower CSF Aß(42). CONCLUSIONS: These results confirm preclinical POM studies, demonstrate that pharmacologically relevant drug/metabolite levels reach brain and support the continued clinical optimisation and evaluation of Posiphen for MCI and Alzheimer's disease.

The cholinesterase inhibitor physostigmine for the local treatment of dry mouth: a randomized study.

Application of physostigmine to the oromucosal surface with the aim of stimulating underlying mucin-producing glands while reducing cholinergic systemic effects might be a strategy for treating dry mouth. Subjects suffering from dry mouth and with hyposalivation participated in a crossover, double-blind, randomized study. A gel containing physostigmine (0.9, 1.8, 3.6, and 7.2 mg) or placebo was applied to the inside of the lips and distributed with the tongue. The feeling of dryness was assessed using a visual analogue scale (VAS) (where a score of 100 = extremely dry) and systemic effects were registered. Based on assessments of efficacy and safety, the dose of 1.8 mg of physostigmine was selected for use in the second part of the study to make objective measurements of saliva volumes. Physostigmine (1.8 mg) produced long-lasting (120 min) relief (evident as a score reduction of 25 on the VAS) in the feeling of dryness. Judging from AUC values related to baseline over 180 min, the improvement for both mouth and lips in response to physostigmine was six times greater than that to placebo. At higher doses of physostigmine, gastrointestinal discomfort predominantly occurred. The volume of saliva collected in response to physostigmine was five times higher over 180 min than that collected in response to placebo. Physostigmine, applied locally, therefore appears to be a promising modality for dry-mouth treatment.

Antiparkinson drugs used as prophylactics for nerve agents: studies of cognitive side effects in rats.

Antiparkinson agents possess excellent anticonvulsant properties against nerve agent-induced seizures by exerting both cholinergic and glutamatergic antagonisms. It is important, however, that drugs used as prophylactics not by themselves cause impairment of cognitive capability. The purpose of the present study was to make a comparative assessment of potential cognitive effects of benactyzine (0.3 mg/kg), biperiden (0.11 mg/kg), caramiphen (10 mg/kg), procyclidine (3 mg/kg), and trihexyphenidyl (0.12 mg/kg) separately and each in combination with physostigmine (0.1 mg/kg). The results showed that benactyzine, caramiphen, and trihexyphenidyl reduced rats' innate preference for novelty, whereas biperiden and procyclidine did not. When benactyzine, caramiphen, and trihexyphenidyl were combined with physostigmine the cognitive impairment disappeared. This counteracting effect, however, caused changes in locomotor and rearing activities not seen by each drug alone. Acetylcholinesterase inhibitors and anticholinergics used as prophylactics can offset each other, but exceptions are observed in a previous study when a very potent anticholinergic (scopolamine) or a high dose of procyclidine still results in cognitive deficits in spite of coadministration with physostigmine. Among the present drugs tested, procyclidine appears to be a robust anticonvulsant with few cognitive side effects.

Physostigmine and anaesthesia emergence delirium in preschool children: a randomized blinded trial.

BACKGROUND: A significant proportion of preschool children experiences severe emergence agitation after anaesthesia. The symptoms of disorientation, restlessness, inconsolable crying and thrashing resemble an acute psychosis similar to an agitated central anticholinergic syndrome. The primary aim of this randomized controlled study was to assess the efficiency of the cholinesterase-inhibitor physostigmine in these children and to identify adverse effects. METHODS: We anaesthetized 211 children (1-5 yr) with sevoflurane after midazolam premedication for varying operative procedures. Multimodal intraoperative and prophylactic pain therapy combined alfentanil, piritramide, diclofenac and regional/local bupivacaine. A 5-step score assessed emergence agitation. Severely agitated children were treated immediately with physostigmine (30 mug kg-1) or placebo in a randomized, double-blind fashion. The primary variable was the agitation score after 5 min. RESULTS: Severe delirium occurred in 19% of all children. Five minutes following injection, severe agitation was still present in 10 out of 20 patients treated with physostigmine and 16/20 with placebo. This difference did not reach statistical significance (P = 0.1). Rescue therapy with intravenous propofol was given after 15 min of severe agitation to four children following physostigmine and nine following placebo (non-significant). An increased rate of postoperative nausea and vomiting (45% vs. 15%, P < 0.05) was the only adverse effect observed. CONCLUSIONS: Severe emergence agitation might be related to a central anticholinergic syndrome as diagnosed empirically with a successful treatment with physostigmine. However, the results of this study do not support its routine use. The substance may augment the therapeutic options if injected slowly and after suitable prophylaxis to avoid postoperative nausea and vomiting.

[Therapy of cognitive deficits in schizophrenia with acetylcholinesterase inhibitors. A systematic overview]. / Therapie kognitiver Defizite durch AChE-Hemmer bei Patienten mit Schizophrenie. Eine systematische Ubersicht.

Patients with schizophrenia suffer from cognitive deficits which are important predictors of functional outcome. Alterations such as reduced muscarinic and nicotinic receptors in the central cholinergic system in patients with schizophrenia may contribute to these cognitive impairments. Because such deficits do not respond to neuroleptic treatment, different approaches have been developed regarding pharmacological treatments that enhance central cholinergic transmission, e.g. with acetylcholinesterase inhibitors. In this review the pathophysiology of cognitive impairment in schizophrenia, results of studies using acetylcholinesterase inhibitors (donepezil, rivastigmine, physostigmine, and galantamine), and future research strategies are presented. Till now randomized, placebo-controlled studies exist only for donepezil and rivastigmine, and none could replicate the positive results of previous trials with open designs. More trials with higher numbers of patients are needed, particularly for substances with more complex mechanisms of action (e.g. galantamine).

Physostigmine: is there a role for this antidote in pediatric poisonings?

PURPOSE OF REVIEW: Ingestion of anticholinergic medications is common in pediatrics. Toxicity may result in symptoms such as severe agitation requiring physical restraint. Physostigmine, an antidote for anticholinergic poisoning, could be useful in this situation. Many physicians are hesitant to use physostigmine after case series suggested its use in tricyclic antidepressant overdose was associated with asystole. This paper reviews the anticholinergic toxidrome and pathophysiology, recent literature on the efficacy and toxicity of physostigmine, and its dosing, indications, and contraindications. RECENT FINDINGS: Recent articles suggest that toxicity associated with physostigmine consists mostly of seizures and cardiac arrhythmia, and occurs when used in the absence of anticholinergic symptoms. Despite potential complications, physostigmine has been shown to be useful in cases of confirmed anticholinergic poisoning by controlling agitation and reversing delirium, and appears to be safer and more effective than benzodiazepines in this situation. SUMMARY: In the proper clinical situation such as pure anticholinergic overdose with severe symptoms, physostigmine can be beneficial. The potential for side effects is not insignificant, and the antidote should be used with caution in any patient with unknown ingestions or those with cardiac conduction defects. More research is needed, especially involving children, before we will fully understand the indications and toxicities associated with physostigmine.