Andis Graudins

A comparison of physostigmine and benzodiazepines for the treatment of anticholinergic poisoning

STUDY OBJECTIVE To compare the efficacy and safety of physostigmine with benzodiazepines for the treatment of agitation and delirium associated with anticholinergic poisoning. METHODS We conducted a retrospective study of 52 consecutive patients referred to a university hospital toxicology consultation service who were treated with physostigmine, benzo-diazepines, or both for anticholinergic agitation and delirium. Patients treated with physostigmine were compared with those treated with benzodiazepines with respect to demographics, severity of poisoning, response to treatment, side effects of treatment, and complications. RESULTS Physostigmine controlled agitation and reversed delirium in 96% and 87% of patients, respectively. Benzodiazepines controlled agitation in 24% of patients but were ineffective in reversing delirium. Initial treatment with physostigmine (n=30) resulted in a significant decrease in the incidence of agitation (P <.001) and level of central nervous system stimulation (P <.001), whereas initial treatment with benzodiazepines (n=22) did not (P =.03 and P =.05, respectively). Patients treated initially with physostigmine had a significantly lower incidence of complications (7% versus 46%; P <. 002) and a shorter time to recovery (median, 12 versus 24 hours; P =. 004) than those treated initially with benzodiazepines. There were no significant differences between these groups in the incidence of side effects (7% versus 14%; P =0.6) and length of stay (median, 32 versus 39 hours; P =.15). CONCLUSION Results suggest that physostigmine is more effective and safer than benzodiazepines for the treatment of anticholinergic agitation and delirium. A prospective controlled study is necessary to confirm such findings.

Delayed Peak Serum Valproic Acid in Massive Divalproex Overdose—Treatment with Charcoal Hemoperfusion

BACKGROUND Increased clearance and apparent clinical improvement in valproic acid overdose has been reported following in-series hemodialysis/hemoperfusion therapy. We report a case of divalproex sodium and chlorpheniramine overdose treated with charcoal hemoperfusion and multiple-dose activated charcoal. CASE REPORT A 32-year-old female presented alert three hours postingestion of her own medication. Serum valproic acid was 105 micrograms/mL. No anticholinergic toxicity was seen. Despite three doses of activated charcoal over 14 hours, serum valproic acid continued to rise. Whole bowel irrigation and multiple-dose activated charcoal were commenced 17 h postingestion when serum valproic acid was 1380 micrograms/mL. Charcoal hemoperfusion was instituted three hours later when serum valproic acid had not fallen and the patient remained obtunded. RESULTS Initial extraction ratio of the hemoperfusion cartridge was 0.54 with plasma clearance of 54.5 mL/min. Valproic acid elimination half-life was 3 h during the 190 min hemoperfusion cycle. Posthemoperfusion elimination half-life was 4.8 h with continued multiple-dose activated charcoal dosing. The clinical condition improved during hemoperfusion. CONCLUSION Enteric coated valproic acid preparations may cause delayed toxicity in overdose, particularly with coingested anticholinergic medications. In our case, charcoal hemoperfusion appeared to increase valproic acid clearance.

Regional intravenous infusion of calcium gluconate for hydrofluoric acid burns of the upper extremity

STUDY OBJECTIVE To describe regional intravenous infusion of calcium gluconate as a therapy for hydrofluoric acid (HF) burns of the forearm, hand, or digits. METHODS This study describes seven patients with HF burns. Calcium gluconate, 10 mL of 10% solution with 30 to 40 mL normal saline solution, was injected intravenously into the affected limb using a Bier block technique. Ischemia was maintained for 20 to 25 minutes. Therapy was considered successful if significant reduction of pain and tenderness was noted after tourniquet release. RESULTS Seven patients were treated. HF concentration varied from 5% to 49%. Exposure sites included the forearm (two cases), thenar eminence and digits (two cases), or digits only (three cases). Complete pain resolution occurred on tourniquet release in four patients (two with burns to the forearm, two with burns to digits only). One patient had partial relief (thenar but not digital exposure site), and two had no relief of symptoms. Intraarterial calcium gluconate perfusion was subsequently administered to the three patients with persistent subungual and pulp, or thenar pain. Recovery was complete in all cases. No adverse effects were noted. CONCLUSION Regional intravenous infusion of calcium gluconate should be considered a therapeutic option in HF burns of the forearm, hand, or digits when topical therapy fails.

Clinical and in vitro evidence for the efficacy of Australian red-back spider (Latrodectus hasselti) antivenom in the treatment of envenomation by a Cupboard spider (Steatoda grossa).

We report the case of a 22-year-old female who was bitten on the shoulder by a spider subsequently identified as a female Cupboard spider (Steatoda grossa). She developed nausea, vomiting, and severe local and regional pain, similar to that seen in latrodectism. Symptoms were treated successfully with red-back spider antivenom (RBSAV). We also present in vitro data, which supports this clinical observation, and suggests that S. grossa venom is immunogenically reactive with both RBSAV and latrotoxin (LTx)-specific antibodies by Western blotting. Moreover, the effects of S. grossa venom on the isolated chick biventer cervicis nerve-muscle preparation are dose-dependent and similar to those seen with Latrodectus spp. venoms. S. grossa venom produced a sustained muscle contracture which could be prevented by pre-incubation of venom with RBSAV. Venom effects could also be reversed by the addition of antivenom after application of venom to the preparation. Although severe envenomation is uncommon following the bite of Steatoda spp. it may resemble latrodectism. These results indicate that RBSAV is likely to be effective in reversing symptoms of envenomation and should be considered in the treatment of patients with distressing or persisting symptoms.

Fluoxetine-induced cardiotoxicity with response to bicarbonate therapy

This report describes a patient with an acute intentional fluoxetine exposure who developed unique cardiovascular and neurovascular toxicity. The patient presented with lethargy and cardiac conduction delays (QRS 110 msec, QTc 458 msec) and developed a delayed seizure. On admission, therapy with intravenous sodium bicarbonate promptly narrowed the QRS to 90 msec. A comprehensive toxicology screen demonstrated only a serum fluoxetine concentration of 901 ng/mL (therapeutic range, 37-301), a serum norfluoxetine concentration of 451 ng/mL (29-329) and a serum acetaminophen concentration of 174 mg/L. Tricyclic antidepresants were specifically noted to be absent. A self-limiting generalized seizure was witnessed 16 hours after ingestion. At this time the bicarbonate infusion had been ceased and the QRS interval was not prolonged. The patient improved over time and no other apparent causes for the observed clinical effects could be discovered. Emergency physicians need to be aware of the uncommon occurrence of fluoxetine-induced cardiotoxicity and the potential benefit of sodium bicarbonate therapy.

Triethylene glycol poisoning treated with intravenous ethanol infusion.

INTRODUCTION Poisoning with triethylene glycol has been rarely reported in humans. Triethylene glycol is thought to be metabolized by alcohol dehydrogenase to acidic products resulting in the production of a metabolic acidemia. Triethylene glycol metabolism has previously been shown to be inhibited by fomepizole (4-methyl pyrazole) administration. We report a case of triethylene glycol ingestion, presenting with a metabolic acidemia, treated with intravenous ethanol administration. CASE REPORT A 23-year-old female presented to the emergency department approximately 1-1.5 hours following ingestion of a gulp of triethylene glycol (99%) brake fluid with coma (GCS-3) and metabolic acidemia (pH 7.03, PCO2 44 mm Hg, Bicarbonate 11 mmol/L, anion gap 30 mmol/L, serum creatinine 90 mumol/L). She was intubated and given 100 mmol of intravenous sodium bicarbonate. An ethanol loading dose was administered followed by an infusion to maintain serum ethanol at 100 mg/dL. Acidemia gradually resolved over the next 8 hours and she was extubated 12 hours later. The ethanol infusion was continued for a total of 22 hours. There was no recurrence of acidemia. Serum ethanol, ethylene glycol, and methanol levels were nondetectable on presentation, as was serum salicylate. Urine drug of abuse screen and thin-layer chromatography revealed no other coingested substances. The patient was discharged to a psychiatric ward 36 hours postingestion. CONCLUSION Pure triethylene glycol poisoning results in coma and metabolic acidemia and may be treated with alcohol dehydrogenase inhibitors such as ethanol.

A Comparison of the Pharmacokinetics of Oral and Sublingual Cyproheptadine

Background: Cyproheptadine is reported to be effective in treating serotonin syndrome. It is only available as an oral preparation and administration after SSRI overdose treated with activated charcoal is problematic. Sublingual administration may circumvent this problem. The pharmacokinetics of sublingual cyproheptadine are not characterized. This study compares the pharmacokinetics of cyproheptadine following oral and sublingual administration. Methods: Cross‐over, non‐blinded, volunteer study using five healthy males. Eight milligrams of oral and sublingual cyproheptadine were administered on separate occasions with a one‐week washout period. Sublingual arm subjects were pretreated with 50 g of oral activated charcoal 30 min prior to cyproheptadine, to prevent any gut absorption. Serum cyproheptadine concentration was measured at baseline, 30 min, and 1, 2, 3, 4, 6, 8, and 10h by liquid chromatography and mass spectroscopy. Results: Mean Cmax for oral and sublingual were 30.0 µg/L and 4.0 µg/L respectively; mean Tmax were 4h and 9.6h; mean AUC were 209 and 25 µg.hr/L. Mean ± SEM within‐subject difference between oral and sublingual Cmax was 25.9 ± 4.1 (p = 0.003) and AUC was 184 ± 31 (p = 0.004). Conclusions: Serum concentrations after sublingual cyproheptadine are significantly less than after oral administration. At these concentrations, the sublingual route is unlikely to be effective in treating serotonin syndrome.