Fatal theophylline poisoning with rhabdomyolysis. A potential role for dantrolene treatment

The characteristics and costs of severe theophylline toxicity in a tertiary critical care unit in Eastern Cape Province, South Africa

Background. Severe theophylline toxicity requiring haemodialysis accounts for approximately one-third of drug toxicity cases admitted to the Livingstone Tertiary Hospital (LTH) intensive care unit (ICU) in Gqeberha, South Africa, imposing a significant resource burden. Objectives. To investigate the characteristics and burden of severe theophylline toxicity in an Eastern Cape Province tertiary hospital adult ICU. Methods. A retrospective review of all severe theophylline toxicity admissions to the ICU from 1 January 2013 to 31 December 2018 was conducted. Demographic and clinical data were captured and analysed. The National Department of Health 2019 fees schedule was used to calculate costs based on duration of ICU stay and number of haemodialysis sessions received. Results. Of the 57 patients included in the study, 84% were cases of deliberate self-harm. The majority were aged <40 years (77%) and female (79%). The mean (standard deviation (SD)) initial serum theophylline level was 612 (269) µmol/L. Complications included convulsions (n=12; 21%), arrhythmias (n=9; 16%), need for mechanical ventilation (n=7; 12%) and death (n=4; 7%). The main risk factors for these complications were age ≥30 years, an inappropriately normal or elevated initial serum potassium level, an elevated serum creatinine kinase level and an elevated initial serum theophylline level. Receiver operator characteristic curve analysis assessing the initial serum theophylline level as a discriminator for life-threatening complications produced an area under the curve of 0.71 for serum theophylline >400 µmol/L (sensitivity 88%, specificity 12%). All the 4 patients who died had an initial serum theophylline level >1 000 µmol/L. The mean (SD) cost per admission amounted to ZAR16 897 (10 718), with a mean of one 4-hour dialysis session per admission. Conclusion. Severe theophylline toxicity, usually in the context of  deliberate self-harm, is a preventable yet life-threatening toxicity encountered at  LTH.  Demographic  risk factors include young females from certain areas in and around Gqeberha.  Risk factors for complications include older age, paradoxically normal or elevated serum potassium levels, elevated serum creatinine kinase levels and an initial serum theophylline level >400 µmol/L. Patients with these clinical features should be closely monitored and treated timeously at an appropriate level of care. The need for ICU admission and dialysis, both limited resources, makes the treatment of severe theophylline toxicity costly. Further studies of the underlying psychosocial drivers, local prescribing practices and preventive interventions related to severe theophylline toxicity are required.

Severe Headache as a Chief Presentation of Theophylline Intoxication

We describe a case of acute on chronic theophylline intoxication with severe headache as the chief complaint in a Chronic Obstructive Pulmonary Disease (COPD) patient. Headache is a non-specific symptom. The intensity of headache is unusually severe in our patient, and is much worse than the headache commonly encountered by an experienced emergency physician.

Drug-induced hyperthermic syndromes: part I. Hyperthermia in overdose

Drugs and natural compounds that affect the thermoregulatory system can induce or contribute to hyperthermia when used in excess. Hyperthermia associated with drug overdose is dangerous and potentially lethal. This article reviews the body's process of maintaining thermodynamic equilibrium, and describes the mechanisms by which it is influenced by sympathomimetic and anticholinergic drugs, salicylates, and thyroid replacement medications. Appropriate treatment strategies such as cooling and the administration of counteractive medications are discussed.

Effects of Theophylline on Anesthetized Malignant Hyperthermia-Susceptible Pigs

Background. Theophylline was shown to induce contracture development in porcine malignant hyperthermia (MH) susceptible (MHS) skeletal muscles in vitro. The purpose of the current study was to investigate the in vivo effects of theophylline in MHS and MH normal (MHN) swine. Methods. MH-trigger-free general anesthesia was performed in MHS and MHN swine. Theophylline was administered intravenously in cumulative doses up to 93.5 mg·kg⁻¹. The clinical occurrence of MH was defined by changes of central-venous pCO₂, central-venous pH, and body core temperature. Results. Theophylline induced comparable clinical alterations in the anesthetized MHS and MHN swine, especially in regard to hemodynamic data. No pig developed hypermetabolism and/or MH according to defined criteria. All animals died with tachycardia followed by ventricular fibrillation. Conclusions. The cumulative theophylline doses used in this study were much higher than doses used therapeutically in humans, as demonstrated by measured blood concentrations. Theophylline is thus not a trigger of MH in genetically determined swine.

Clinical review: Treatment of heat stroke: should dantrolene be considered?

Rapid and efficient cooling is the most important therapeutic objective in patients with heat stroke (HS). This article reviews the mechanism of action and rationale for the use of dantrolene as a potential supportive cooling method in the treatment of HS. Relevant studies were included to support discussion of the role of dantrolene for the treatment of HS. In some studies dantrolene was shown to accelerate cooling rate when administered after the development of exertional HS. Dantrolene was also found to be effective in reducing the extent of HS signs when given as pretreatment in an animal model. Accumulated data do not support the routine use of dantrolene as an adjuvant cooling technique in HS, but administration of this drug in severe cases, or in which no improvement is observed, appears rational. Further trials are needed in order to assess the true effectiveness of dantrolene in HS.

Extracorporeal therapies for acute intoxications

Intoxications frequently perturb acid-base and electrolyte status, intravascular volume, and renal function. In selected cases, extracorporeal techniques effectively restore homeostasis and augment intoxicant removal. The use of 4-methylpyrazole, an inhibitor of alcohol dehydrogenase, is a new and effective treatment for patients exposed to toxic alcohols. In this section, practical approaches to commonly encountered intoxicants and the use of extracorporeal techniques are critically reviewed.

Exertional heat stroke induced by amphetamine analogues. Does dantrolene have a place?

There are increasing numbers of patients admitted to hospital as a result of ingesting amphetamine-like drugs. The most severe cases exhibit hyperthermia, rhabdomyolysis, coagulopathy and renal failure. We describe six such patients with varying severity of intoxication, and have reviewed the recent literature with particular reference to the use of dantrolene. One of our patients died but the others all survived. There is little evidence that dantrolene influenced the outcome in patients reported to date. We believe that a controlled trial should be carried out in amphetamine-related hyperthermia before the use of dantrolene becomes widespread.

Rhabdomyolysis following life-threatening acute asthma attack

The authors report a life-threatening, acute asthmatic attack in a young man, which was followed by rhabdomyolysis and acute myoglobinuria. A discussion of the possible rôle of the pharmacological treatment of asthma in initiating muscle damage is included, based on a review of the current literature.

An overdose of ecstasy

An overdose of the semisynthetic, hallucinogenic amphetamine 3,4-methylenedioxymethamphetamine resulted in convulsions, hyperthermia, hyperkalaemia and rhabdomyolysis. The patient's management, which included the use of dantrolene, is discussed.