Use of pralidoxime without atropine in rivastigmine (carbamate) toxicity

Opposite changes in blood pressure and pulse rate in two patients with distigmine and rivastigmine intoxication

Background

Cholinergic crisis caused by cholinesterase inhibitors is rare but life-threatening. Clinical manifestations are thought to be similar to those caused by organophosphates.

Case presentation

A 77-year-old woman on a standard dose of distigmine presented with impaired consciousness, blood pressure (BP) of 69/40 mmHg, a pulse rate (PR) of 60 beats/min, miosis, bronchorrhea, and serum cholinesterase (ChE) of 8 IU/L. After discontinuation of distigmine, altered mental status and pupil miosis were gradually resolved in 5 days with a concomitant increase of serum ChE. A 91-year-old woman presented with a headache, BP of 202/86 mmHg, PR of 83 beats/min, miosis, 9 rivastigmine patches on her knees, and ChE of 22 IU/L. The day after close observation without rivastigmine use, her symptoms were almost resolved with a concomitant increase of serum ChE.

Conclusion

Our cases and a literature review suggested that, in contrast to distigmine, rivastigmine-induced cholinergic crisis caused hypertension and tachycardia.

Successful Resuscitation of a Young Girl Who Drank Rivastigmine With Respiratory Failure

Rivastigmine is a non-competitive reversible inhibitor of acetylcholinesterase which is approved as one of the fi rst-line treatment options for Alzheimer's disease. We present the case of a 33-year-old woman with acute cholinergic syndrome secondary to deliberate rivastigmine poisoning. The patient presented at the emergency department (ED) with drowsy consciousness, dizziness, vomiting, diarrhea, sweating, and hypertension (171/103 mmHg). At the scene, an empty bottle of Rivast 120 mL/Bot, containing rivastigmine 2 mg/mL, was found beside the patient. Two hours later, we noted bronchorrhea and persistent salivation along with drowsiness, agitation, fatigue, incontinence, and limbs paralysis. A notably low serum cholinesterase level (651 U/l) was identified. Acute cholinergic syndrome secondary to rivastigmine intoxication was diagnosed. Endotracheal intubation with ventilator support was required due to respiratory failure. Atropine (0.5 mg intravenous injection) was administered. She was subsequently admitted to the intensive care unit for further care. Extubation was performed on the third day. The patient insisted on being discharged on the second day after extubation, and after administration of a total of 11 mg of atropine, no signs of either intermediate syndrome or delayed polyneuropathywere noted. rivastigmine, an acetylcholinesterase inhibitor, can precipitate an acute cholinergic crisis in cases of intoxication. Typical clinical features of cholinergic excess include increased secretions in the airway and oral cavity, miosis, diarrhea, anxiety, twitching, bronchoconstriction, convulsions, confusion, and gastrointestinal and muscular cramps. The treatment for acute cholinergic crisis is administration of atropine alone or in combination with an antidote to the cholinesterase inhibitor (such as pralidoxime). Patients often recover well with atropine supplements and optimal supportive care.

The First Use of Pralidoxime in a Child With Rivastigmine Poisoning

The aim of this report is to describe the successful use of pralidoxime in a pediatric patient who accidentally ingested 12 mg of rivastigmine and presented to the emergency department with weakness, drowsiness, hyporeactivity to environmental stimuli, and full cholinergic syndrome.

CASE

The patient presented to the emergency department 2 hours after a suspected ingestion of rivastigmine. He was sleepy but oriented and cooperative, hypotonic, and hyporeflexic and has a Glasgow Coma Scale score of 13 (E3M6V4). Laboratory tests showed a low plasma cholinesterase levels of 2141 U/L (reference range, 5300-12 900 U/L), hyperglycemia (251 mg/dL), and leukocytosis with neutrophilia (21 900/mL, 75.2% neutrophils).

CONCLUSIONS

Only 2 pediatric cases of rivastigmine poisoning have been reported in the literature, and there are no previous reports of using pralidoxime in the management of this poisoning. In the present case, intravenous pralidoxime (30 mg/kg) was administered twice at the fifth and sixth hours of ingestion for nicotinic and central effects. There is reasonable theoretical science to suggest pralidoxime in case of acetylcholinesterase inhibitor toxicity. We conclude that observed clinical improvement in weakness temporally associated with pralidoxime administration. Increased plasma cholinesterase activity after pralidoxime administration also makes it useful in this type of poisoning.

Acute cholinergic syndrome in a patient with mild Alzheimer's type dementia who had applied a large number of rivastigmine transdermal patches on her body

CASE PRESENTATION

A 91-year-old woman was transferred to our Emergency Medical Center and Poison Center with somnolence, hypertension (186/61 mm Hg), and repeated vomiting. Three hours later, 10 transdermal patches, each containing 18 mg of rivastigmine (9.5 mg/24 h), were found on her lower back and both thighs, when miosis, facial and trunk sweating, enhanced bowel sound, hypertension, and sinus tachycardia were noted. She was diagnosed with acute cholinergic syndrome due to rivastigmine poisoning. Her hypertension and sinus tachycardia peaked 8 and 5 h after all the patches were removed, respectively. Her symptoms subsided spontaneously after 17 h.

DISCUSSION

In the present case, our patient was presented with acute cholinergic syndrome due to carbamate intoxication after massive transdermal exposure to rivastigmine. Toxicological analysis revealed a remarkably high estimated serum rivastigmine concentration (150.6 ng/ml) and notably low serum butyrylcholinesterase activity (35 IU/l) on admission, with a markedly prolonged calculated elimination half-life of 6.5 h.

CONCLUSIONS

Emergency physicians should consider acetylcholinesterase inhibitor exposure (e.g., rivastigmine) when patients are present with acute cholinergic syndrome.

Characteristics of Pediatric Exposures to Antidementia Drugs Reported to a Poison Control System

OBJECTIVE

To characterize pediatric exposures to the antidementia drugs donepezil, memantine, rivastigmine, and galantamine by reviewing a poison control system's database.

STUDY DESIGN

A retrospective review of a statewide poison control system's database identified cases of pediatric (less than 19 years of age) exposures to antidementia drugs over an 11-year period. Data collected included age, sex, drug(s) involved, route of exposure, reason for exposure, symptoms, and interventions.

RESULTS

There were 189 cases identified (53% male, median age: 2.3 years, 99% unintentional exposures). Donepezil was the most commonly reported exposure (106 cases), followed by memantine (57), galantamine (18), oral rivastigmine (16), and transdermal rivastigmine (3). Coingestants were reported in 68 (36%) cases. Symptoms were reported in 38 (20%) cases. Gastrointestinal symptoms were most common (n = 21) followed by central nervous system depression (n = 15). Oral rivastigmine was associated with higher rates of symptoms. No bradycardia, seizures, or fasciculations were reported. Eighty-nine cases (47%) were evaluated at a health care facility, and 13 (7%) were admitted to a hospital. Oral rivastigmine exposures were associated with increased rate of health care facility evaluation. Activated charcoal was administered in 28 cases. Atropine was given only once, for drooling. There were no serious outcomes or deaths in this series.

CONCLUSIONS

Reported pediatric exposures to antidementia drugs resulted in minimal morbidity and no mortality. Oral rivastigmine exposures were found to be associated with more symptoms and health care facility evaluations.

Medication errors related to transdermal opioid patches: lessons from a regional incident reporting system

OBJECTIVE

A few cases of adverse reactions linked to erroneous use of transdermal opioid patches have been reported in the literature. The aim of this study was to describe and characterize medication errors (MEs) associated with use of transdermal fentanyl and buprenorphine.

METHODS

All events concerning transdermal opioid patches reported between 2004 and 2011 to a regional incident reporting system and assessed as MEs were scrutinized and characterized. MEs were defined as "a failure in the treatment process that leads to, or has the potential to lead to, harm to the patient".

RESULTS

In the study 151 MEs were identified. The three most common error types were wrong administration time 67 (44%), wrong dose 34 (23%), and omission of dose 20 (13%). Of all MEs, 118 (78%) occurred in the administration stage of the medication process. Harm was reported in 26 (17%) of the included cases, of which 2 (1%) were regarded as serious harm (nausea/vomiting and respiratory depression). Pain was the most common adverse reaction reported.

CONCLUSIONS

Of the reported MEs related to transdermal fentanyl and buprenorphine, most occurred during administration. Improved routines to ascertain correct and timely administration and educational interventions to reduce MEs for these drugs are warranted.