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Clinical and demographic features with outcome predictors of adult patients with acute intoxication admitted to a medical intensive care unit in the Mediterranean part of Croatia

Background

The objective of the study was to assess the demographics, clinical parameters, and outcome of acute intoxications among adult patients admitted to a medical intensive care unit in southern Croatia.

Materials and Methods

An observational retrospective study was conducted over a 1-year period. The subjects were patients admitted to the intensive care unit for acute poisoning.

Results

In all, 81 subjects (32.1% females) aged 43.16 ± 14.77 years were admitted to the intensive care unit because of poisoning (14.97% of the total annual intensive care unit admissions). Psychiatric disorders were previously established in 76.5% participants, and 69.1% of all acute intoxications were classified as suicidal. Non-suicidal subjects differed from suicidal subjects in age (37.36 ± 9.71 vs. 45.75 ± 15.93 years; P = 0.009), in pCO2 (6.38 ± 1.78 vs. 5.50 ± 1.26 kPa; P = 0.020), in length-of-stay in intensive care unit (median 1.00, interquartile range 1.00 vs. median 2.00, interquartile range 2.00 days; P = 0.022), and in length-of-stay in hospital (median 2.00, interquartile range 2.00 vs. median 10.50, interquartile range 15.25 days; P < 0.001). Three (3.7%) patients died. Pharmaceutical psychoactive drug intoxications were the most common poisoning cases; of these, diazepam was the most frequent (16.8%), followed by ethanol (9.0%) and alprazolam (7.8%). Benzodiazepines/hypnotics were the most common group (28.7%), followed by antipsychotics (13.2%). Intoxications with more than 1 poison accounted for the largest number of cases (67.9%). The number of toxins was significantly correlated with length-of-stay in the hospital (rho = -0.265; P = 0.008), systolic blood pressure (rho = -0.318; P = 0.002), and diastolic blood pressure (rho = -0.262; P = 0.009). The electrocardiogram was considered abnormal in 50.62% of the cases.

Conclusion

Acute intoxicants were most commonly caused by psychiatric pharmaceutical drugs. Multidrug exposure was a typical pattern of acute intoxication.

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BACKGROUND

Methylene blue is used in medical practice for various reasons. Recent findings point to a potential interaction with serotonin reuptake inhibitors (SRIs) that could lead to serotonergic toxicity.

OBJECTIVE

To describe the risk of serotonergic toxicity associated with the interaction between methylene blue and SRIs.

DATA SOURCES

Relevant publications were searched systematically via MEDLINE (1946 to March 21, 2013) and Embase (1974 to 2013, week 11) with the following search terms: "methylene blue", "methylthioninium", "monoamine oxidase inhibitors", "serotonin reup-take inhibitors", and "serotonin syndrome". No restrictions were applied in relation to the indication for methylene blue or the language of publication. The reference lists of identified articles were also searched.

STUDY SELECTION AND DATA EXTRACTION

Eighteen case reports and 2 case series were identified for inclusion. To date, no randomized controlled trials have been published.

DATA SYNTHESIS

The first case report indicating suspicion of an interaction between methylene blue and SRIs was published in 2003. Seventeen other case reports describing the same type of interaction have been published since then. The 2 case series provided data from about 325 parathyroidectomies in which methylene blue was used for staining. The 17 patients who experienced central nervous system toxicity were all taking SRIs in the preoperative period.

CONCLUSION

When administered in combination with SRIs, methylene blue may lead to serotonergic toxicity at doses as low as 0.7 mg/kg. Methylene blue would seem to have monoamine oxidase A inhibitory properties. Precautions should be taken to avoid this interaction. [Publisher's translation].