Non-traumatic rhabdomyolysis complicating antihistamine overdose

Clinical and patient characteristics associated with severe outcome in diphenhydramine toxicity

BACKGROUND

Diphenhydramine is frequently misused and ingested recreationally for its antihistaminergic and antimuscarinic effects and is often involved in both serious and fatal poisonings, either in isolation or in combination with other xenobiotics.

OBJECTIVE

This analysis sought to determine which patient and encounter characteristics were associated with severe outcome after diphenhydramine overdose.

METHODS

This is an analysis of the multi-center ToxIC registry (2010-2016). Descriptive analysis of all cases with diphenhydramine listed as the "primary agent" contributing to toxicity were included. Analysis sought to determine which patient and encounter characteristics were associated with severe outcome, defined as occurrence of seizure, ventricular dysrhythmia, or intubation. To determine which patient and encounter characteristics were individually associated with severe outcome, we performed chi-square tests. Fisher's exact tests were used in the case of sparse data. We also performed multivariable logistic regression to further determine independent risk factors for severe outcome in diphenhydramine overdose.

RESULTS

Eight hundred and sixty-three cases remained after exclusion with 15.6% (n = 135) of all patients having one or more severe outcome. The most common severe outcome was seizures which occurred in 98 (11.6%) of all ingestions. Females comprised 59.1% (n = 510) of all ingestions. Most ingestions were intentional (86.0%, n = 742) with the most common known reason for an intentional ingestion being self-harm, accounting for 37.5% (n = 324) of all ingestions. Self-harm ingestions and ingestions in males were more commonly associated with intubation. When examining outcomes by age, there were no significant differences overall or in any individual outcome except intubation in which children 0-12 were less likely to be intubated as compared to teens and adults. Signs and symptoms most strongly associated with a severe outcome included acidemia (pH < 7.2), QRS prolongation (QRS > 120 ms), and elevated anion gap (AG > 20).

DISCUSSION

Acidemia, QRS prolongation, and elevated anion gap are associated with severe outcomes in diphenhydramine toxicity. Further research is warranted to determine their predictive characteristics.

Risk factors for delayed-onset rhabdomyolysis in doxylamine succinate intoxication patients

Background and Objectives:

Patients who overdose on doxylamine, hypnotic agent, usually exhibit good outcomes, but some experience serious complications. Some patients who present with normal creatinine phosphokinase levels in the emergency department later develop rhabdomyolysis during observation. We investigated factors associated with delayed-onset rhabdomyolysis in patients with doxylamine overdoses.

Methods:

Our investigation period was between 1 January 2011 and 29 February 2016. The initial blood samples were obtained for arterial blood gas analysis and measurements of the levels of electrolytes, creatinine phosphokinase, blood urea nitrogen, creatinine, aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase. Urine analyses including pH and occult blood analyses were performed. Follow-up samples were obtained at 6 and 12 h after admission. Delayed-onset rhabdomyolysis was defined by a follow-up serum creatinine phosphokinase level greater than fivefold the upper limit of normal (>1000 IU/L). Comparisons of categorical variables between groups were performed using either the χ2 or Fisher exact tests. Continuous variables were compared between groups using the Mann–Whitney U test.

Results:

A total of 337 patients were enrolled. The large amount of ingested doxylamine (odds ratio = 7.002), tachycardia (odds ratio = 2.809), low arterial blood gas analysis pH (odds ratio = 2.267), and presence of occult blood in the urine (odds ratio = 2.048) were significant associated with delayed-onset rhabdomyolysis.

Conclusion:

Laboratory follow-up examinations were required for patients, ingested more than 18 mg/kg doxylamine poisoning, who had pulses exceeding 120 beats/min, had arterial blood gas analysis pH values below 7.3 on blood and urine testing, and/or exhibited the presence of occult blood in the urine, even if the initial creatinine phosphokinase level was normal.

Risk factors for rhabdomyolysis following doxylamine overdose

The objective of this prospective study was to identify risk factors for developing rhabdomyolysis in patients with doxylamine overdose. Patients who were admitted to a university teaching hospital between July 2000 and September 2005 due to doxylamine overdose were recruited. Demographic information, clinical variables, and laboratory data were investigated. Twenty-seven (M/F 12/15, age 33.2 ±13.1 years) patients were enrolled. Sixteen (59%) of 27 patients developed rhabdomyolysis and three (19%) of 16 patients with rhabdomyolysis also developed acute renal failure. Patients who developed rhabdomyolysis differed from those who did not in the amount of doxylamine ingested, initial serum creatitnine and arterial pH. In multivariate regression analysis, the only reliable predictor of rhabdomyolysis was the amount of doxylamine ingested ( P = 0.039). The amount of doxylamine ingested (≥ 20 mg/kg) predicted the development of rhabdomyolysis with a sensitivity of 81%, a specificity of 82%, a positive predictive value of 87%, and a negative predictive value of 75%.

In conclusion, rhabdomyolysis following doxylamine overdose was common, occurring in 87% of patients who ingested more than 20 mg/kg. The amount of doxylamine ingested was the only reliable predictor for developing rhabdomyolysis following doxylamine overdose. Human & Experimental Toxicology (2007) 26, 617—621

Pheniramine Maleate-Induced Rhabdomyolysis and Aki: Is it Fatal?

Pheniramine maleate is an easily accessible, over-the-counterantihistaminic, which is frequently involved in overdoses. Pheniramine has antimuscarinic effect causing tachycardia, dilated pupils, urinary retention, and dry flushed skin, and decreased bowel sounds, confusion, mild increase in body temperature, cardiac arrhythmias, and seizures at lethal doses. It has not been implicated as an important cause of rhabdomyolysis and acute kidney injury (AKI). Rhabdomyolysis causing AKI is rarely reported in the literature. This case report emphasizes the occurrence of nontraumatic rhabdomyolysis in pheniramine maleate overdose which required hemodialysis. Since there is a lack of a specific antidote, treatment is mainly symptomatic and supportive. We report a fatal case of a young male with a very high dose of consumption of pheniramine maleate (4.077 g), which was complicated by seizures, respiratory depression, nontraumatic rhabdomyolysis, and AKI. Despite hemodialysis, ventilator support, and other intensive supportive care, patient could not survive and death ensued due to multiorgan dysfunction syndrome.

The associative factors of delayed-onset rhabdomyolysis in patients with doxylamine overdose

OBJECTIVES

The aim of this study was to investigate the associative factors of rhabdomyolysis in patients with doxylamine overdose who had normal creatine phosphokinase levels at admission.

METHODS

This study included 169 patients who visited the emergency department of a tertiary teaching hospital after doxylamine overdose between January 1, 1998, and March 31, 2009. Demographic information, clinical variables, and laboratory data were investigated for the associative factors of rhabdomyolysis.

RESULTS

Thirty-five (21%) of the 169 patients developed rhabdomyolysis. Patients who developed rhabdomyolysis differed from those who did not in the amount of doxylamine ingested, sex, heart rate, initial value of serum creatinine, and alanine aminotransferase. In the multivariate regression analysis, the only reliable predictors of rhabdomyolysis were the amount of doxylamine ingested (P = .004) and heart rate (P < .001).

CONCLUSION

Observation and laboratory follow-up are required for patients with large reported ingestions or tachycardia on admission, even if their creatine phosphokinase levels were normal.

Acute renal failure caused by pheniramine maleate induced rhabdomyolysis: an unusual case

Antihistamines are easily available over-the-counter medications, which are frequently involved in overdoses. The usual course is accompanied by the anticholinergic effects of these agents. We report a case of a suicide attempt in a young male, where ingestion of antihistamine pheniramine maleate was complicated by nontraumatic rhabdomyolysis and oliguric acute renal failure. Rhabdomyolysis and acute renal failure is a rarely reported but potentially serious complication among patients who present to the emergency after intentional overdoses making recognition and prompt intervention essential. We also describe the potential mechanism of muscle injury in antihistamine overdose.

Comparison of lactated Ringer's solution and 0.9% saline in the treatment of rhabdomyolysis induced by doxylamine intoxication

OBJECTIVE

To compare the effectiveness and side effects of lactated Ringer's solution (LR) and 0.9% saline (NS) in the treatment of rhabdomyolysis induced by doxylamine intoxication.

METHODS

In this 15-month-long prospective randomised single-blind study, after excluding 8 patients among 97 doxylamine-intoxicated patients, 28 (31%) patients were found to have developed rhabdomyolysis and were randomly allocated to NS group (n = 15) or LR group (n = 13).

RESULTS

After 12 h of aggressive hydration (400 ml/h), urine/serum pH was found to be significantly higher in the LR group, and serum Na+/Cl- levels to be significantly higher in the NS group. There were no significant differences in serum K+ level and in the time taken for creatine kinase normalisation. The amount of sodium bicarbonate administered and the frequency administration of diuretics was significantly higher in the NS group. Unlike the NS group, the LR group needed little supplemental sodium bicarbonate and did not develop metabolic acidosis.

CONCLUSION

LR is more useful than NS in the treatment of rhabdomyolysis induced by doxylamine intoxication.

Diphenhydramine and dimenhydrinate poisoning: an evidence-based consensus guideline for out-of-hospital management

In 2003, there were 28,092 human exposures to diphenhydramine reported to poison centers in the US. A related drug, dimenhydrinate, is a less frequent cause of poisonings. Between January 2000 and June 2004, there were 2,534 reported dimenhydrinate ingestions in children less than 6 years of age. An evidence-based expert consensus process was used to create this guideline. Relevant articles were abstracted by a trained physician researcher. The first draft was created by the primary author. The entire panel discussed and refined the guideline before distribution to secondary reviewers for comment. The panel then made changes based on the secondary review comments. The objective of this guideline is to assist poison center personnel in the appropriate out-of-hospital triage and initial management of patients with a suspected ingestion of diphenhydramine or dimenhydrinate, or a dermal exposure to diphenhydramine. This guideline is based on an assessment of current scientific and clinical information. The expert consensus panel recognizes that specific patient care decisions may be at variance with this guideline and are the prerogative of the patient and the health professionals providing care, considering all of the circumstances involved. This guideline does not substitute for clinical judgment. The panel's recommendations for dermal or oral exposures to diphenhydramine or oral exposures to dimenhydrinate follow. The grade of recommendation is in parentheses: 1) All patients with suicidal intent, intentional abuse, or in cases in which a malicious intent is suspected (e.g., child abuse or neglect) should be referred to an emergency department (Grade D). 2) In patients without evidence of self-harm, abuse, or malicious intent, poison center personnel should elicit additional information including the time of the ingestion or dermal exposure, determination of the precise dose ingested, and the presence of co-ingestants (Grade D). 3) Patients experiencing any changes in behavior other than mild drowsiness or mild stimulation should be referred to an emergency department. Examples of moderate to severe symptoms that warrant referral include agitation, staring spells, inconsolable crying, hallucinations, abnormal muscle movements, loss of consciousness, seizures, or respiratory depression (Grade D). 4) For patients referred to the emergency department, transportation via ambulance should be considered based on several factors including the condition of the patient and the length of time it will take the patient to arrive at the emergency department (Grade D). 5) If the patient has no symptoms, and more than 4 hours have elapsed between the time of diphenhydramine ingestion and the call to the poison center, referral to an emergency department is not recommended. For dermal exposures to diphenhydramine, if the patient has no symptoms and it has been more than 8 hours since the diphenhydramine was thoroughly removed from the skin, referral to an emergency department is not recommended (Grade D). 6) Patients with acute ingestions of less than a toxic dose of diphenhydramine, or chronic exposures to diphenhydramine and no or mild symptoms, can be observed at home with instructions to call the poison center back if symptoms develop or worsen. The poison center should consider making a follow-up call at approximately 4 hours after ingestion (Grade D). 7) Children less than 6 years of age who ingest at least 7.5 mg/kg of diphenhydramine should be referred to an emergency department (Grade D). 8) Patients 6 years of age and older who ingest at least 7.5 mg/kg or 300 mg of diphenhydramine (whichever is less), should be referred to an emergency department (Grade D). 9) If the patient has no symptoms, and more than 6 hours have elapsed between the time of dimenhydrinate ingestion and the call to the poison center, referral to an emergency department is not recommended (Grade D). 10) Patients with acute ingestions of less than a toxic dose of dimenhydrinate, or chronic exposures to dimenhydrinate and no or mild symptoms, can be observed at home with instructions to call the poison center back if symptoms develop or worsen. The poison center should consider making a follow-up call at approximately 6 hours after ingestion (Grade D). 11) Children less than 6 years of age ingesting at least 7.5 mg/kg of dimenhydrinate should be referred to an emergency department (Grade D). 12) Patients 6 years of age and older ingesting at least 7.5 mg/kg or 300 mg of dimenhydrinate (whichever is less), should be referred to an emergency department for evaluation (Grade D). 13) Following oral exposures of diphenhydramine or dimenhydrinate, do not induce emesis. Because of the potential for diphenhydramine or dimenhydrinate to cause loss of consciousness or seizures, activated charcoal should not be administered en route to an emergency department (Grade D). 14) For chronic dermal exposures of diphenhydramine, skin decontamination (with water or soap and water) should be attempted prior to transporting a patient to an emergency department unless moderate to severe symptoms are already present. In this circumstance, transportation should not be delayed, and EMS personnel should attempt skin decontamination en route to the emergency department (Grade D). 15) Intravenous sodium bicarbonate may be administered by EMS personnel if QRS widening (QRS >0.10 msec) is present and if authorized by EMS medical direction (Grade D). 16) Physostigmine should be reserved for administration in a hospital (Grade D). 17) Benzodiazepines may be administered by EMS personnel if agitation or seizures are present, and if authorized by EMS medical direction (Grade D).

Rhabdomyolysis: an evaluation of 475 hospitalized patients

Rhabdomyolysis is a common and potentially lethal clinical syndrome that results from acute muscle fiber necrosis with leakage of muscle constituents into blood. Myoglobinuria is the most significant consequence, leading to acute renal failure (ARF) in 15%-33% of patients with rhabdomyolysis. Rhabdomyolysis occurs from inherited diseases, toxins, muscle compression or overexertion, or inflammatory processes, among other disorders. In some cases, no cause is found. We describe 475 patients from the Johns Hopkins Hospital inpatient records between January 1993 and December 2001 for the following discharge diagnosis codes: myoglobinuria, rhabdomyolysis, myopathy, toxic myopathy, malignant hyperthermia, neuroleptic malignant syndrome, and polymyositis. Of 1362 patients, 475 patients with an acute neuromuscular illness with serum creatine kinase (CK) more than 5 times the upper limit of normal (>975 IU/L) were included. Patients with recent myocardial infarction or stroke were excluded. The etiology was assigned by chart review. For all, the highest values of serum CK, serum creatinine and urine myoglobin, hemoglobin, and red blood cells were recorded. Forty-one patients had muscle biopsy within at least 2 months from the onset of rhabdomyolysis.Of the 475 patients, 151 were female and 324 were male (median age, 47 yr; range, 4-95 yr). Exogenous toxins were the most common cause of rhabdomyolysis, with illicit drugs, alcohol, and prescribed drugs responsible for 46%. Among the medical drugs, antipsychotics, statins, zidovudine, colchicine, selective serotonin reuptake inhibitors, and lithium were the most frequently involved. In 60% of all cases, multiple factors were present. In 11% of all cases, rhabdomyolysis was recurrent. Underlying myopathy or muscle metabolic defects were responsible for 10% of cases, in which there was a high percentage of recurrence, only 1 etiologic factor, and a low incidence of ARF. In 7%, no cause was found. ARF was present in 218 (46%) patients, and 16 died (3.4%). A linear correlation was found between CK and creatinine and between multiple factors and ARF, but there was no correlation between ARF and death or between multiple factors and death. Urine myoglobin detected by dipstick/ultrafiltration was positive in only 19%. Toxins are the most frequent cause of rhabdomyolysis, but in most cases more than 1 etiologic factor was present. Patients using illicit drugs or on prescribed polytherapy are at risk for rhabdomyolysis. The absence of urine myoglobin, by qualitative assay, does not exclude rhabdomyolysis. With appropriate care, death is rare.

Antihistamine-induced Rhabdomyolysis

Antihistamines, which are readily available over the counter in sleeping aids, are commonly found in intentional overdoses. We report three new cases of severe rhabdomyolysis related to ingestion of these agents. This is a rarely reported but potentially overlooked complication among patients who present to the emergency center after intentional overdoses. We also describe the potential mechanism of muscle injury in antihistamine overdoses and comment on the potential for cross-reactivity of antihistamines with the urine screen for phencyclidine.

Clinical experience in acute overdosage of diphenidol

BACKGROUND

Diphenidol (Cephadol, Vontrol), an antiemetic agent used in the treatment of vomiting and vertigo, has been reported to cause various adverse effects including drowsiness, hypotension, confusion, hallucination, restlessness, and other antimuscarinic effects. Serious toxic effects might be anticipated after intentional or accidental ingestion.

MATERIALS AND METHODS

Retrospective analysis of all case records of the PCC-Taiwan defining diphenidol overdose during 1985-1996.

RESULTS

The data of 21 patients with diphenidol overdose were analyzed; 17 were < 3 years old and unintentionally poisoned, in contrast to the suicide attempts by four adults. The average amount of ingestion was 222.5 mg with a range of 25-800 mg. Most patients manifested only transient CNS, cardiovascular, or oculo-facial effects, but four children suffered from severe toxicity after an ingestion of 11.7-80 mg/kg diphenidol. Commonly reported toxicity in diphenidol overdose included facial flush (10), tachycardia, restlessness (6), seizures (4), dyspnea, drowsiness, mydriasis, coma, and fever (3). With supportive therapy, a good recovery was the rule except for one fatality of a 2 1/2-year-old boy who ingested 15 mg/kg diphenidol and presented with recurrent seizures, hypotension, respiratory failure, and coma.

CONCLUSIONS

Although not previously reported, accidental diphenidol overdose may result in serious anticholinergic toxicity in children. Treatment is supportive and the therapeutic role of physostigmine in diphenidol poisoning is still unclear.

Rhabdomyolysis: a rare adverse effect of diphenhydramine overdose

Drug- and toxin-induced rhabdomyolysis is a nonspecific clinical syndrome resulting from the release of skeletal muscle cell contents into the plasma and urine. Antihistamine drugs are the active ingredients in a number of over-the-counter preparations and are frequently ingested in suicide attempts. We report rhabdomyolysis as a rare adverse effect of diphenhydramine toxicity in a 29-year-old man who ingested an unknown quantity of an over-the-counter sleep preparation in a suicide attempt. The patient had documented toxic concentration of diphenhydramine in his cerebrospinal fluid and no history of seizures, coma, or hypothermia. A high index of suspicion and an evaluation for rhabdomyolysis is warranted in antihistamine toxicity.