Rapid reversal of life-threatening diltiazem-induced tetany with calcium chloride

Safety and efficacy of prehospital diltiazem

Introduction: Very few studies exist on the use of diltiazem in the prehospital setting. Some practitioners believe this medication is prone to causing hypotension in this setting. Our goals were to determine whether the prehospital administration of diltiazem induced hypotension and to evaluate the efficacy of the drug.

Methods: Our two-tiered system is located in a suburban region of New Jersey with advanced life support (ALS) care provided by fly-car units. The ALS units do not transport patients, and all of them are hospital based. The ALS providers are employed by the hospital system. In New Jersey, all ALS care requires online medical control, including the administration of diltiazem. We retrospectively reviewed patient care records for those who were believed to be in rapid atrial fibrillation and were given diltiazem in a suburban emergeny medical services system over a 22-month period. We examined the differences between heart rate (HR) and blood pressure (BP) on the initial evaluation and on arrival to the emergency department (ED). A hypotensive response was defined as a final systolic BP (SBP) less than 90 mmHg and a drop in SBP of at least 10 mmHg. Diltiazem was considered effective if the ED HR was <100 beats per minute (bpm) or if it decreased ≥20%.

Results: During the study period, 26,979 patients were transported. Of these patients, 2,488 had a documented rhythm of atrial fibrillation or atrial flutter. Of the 320 patients who received diltiazem, 42 patient encounters were excluded for incomplete data, yielding 278 patients for analysis. The average initial SBP was 139 mmHg and the average diastolic BP was 84 mmHg. The average diltiazem dosage was 16.7 mg. Two patients became hypotensive. The average initial HR was 154 bpm. On arrival to the ED, 33% of the patients had an HR < 100 bpm and 69% had a drop in HR ≥ 20%. The overall efficacy of prehospital diltiazem was 73%.

Conclusion: In the prehospital setting, diltiazem is associated with a very low rate of hypotension and appears to be effective in decreasing HR adequately. Prospective studies are needed to confirm these findings.

A review of drug-induced hypocalcemia

Hypocalcemia (defined as total serum calcium lower than 8.5 mg/dl or as ionized serum calcium lower than 4.7 mg/dl) is a relatively common metabolic abnormality observed in hospitalized patients. Although it is associated with certain pharmacological agents such as bisphosphonates and cisplatin, hypocalcemia may occasionally develop in the course of treatment with drugs used in everyday clinical practice, including antiepileptics, aminoglycosides, and proton pump inhibitors. Hypocalcemia associated with drug treatment can be easily missed as a consequence of coexistence of multiple factors contributing to low serum calcium levels. Drug-related hypocalcemia is usually mild and asymptomatic but may be severe as well. Effective clinical management can be handled through awareness of this adverse effect induced by certain pharmaceutical compounds on serum calcium concentrations. Herein, we review pertinent clinical information on the incidence of hypocalcemia associated with specific drug treatment and discuss the underlying pathophysiological mechanisms.

Drug-Induced Endocrine and Metabolic Disorders

Complex interactions exist amongst the various components of the neuroendocrine system in order to maintain homeostasis, energy balance and reproductive function. These components include the hypothalamus-pituitary- adrenal and -gonadal axes, the renin-angiotensin-aldosterone system, the sympathetic nervous system and the pancreatic islets. These hormones, peptides and neurotransmitters act in concert to regulate the functions of many organs, notably the liver, muscles, kidneys, thyroid, bone, adrenal glands, adipocytes, vasculature, intestinal tract and gonads, through many intermediary pathways. Endocrine and metabolic disorders can arise from imbalance amongst numerous hormonal factors. These disturbances may be due to endogenous processes, such as increased secretion of hormones from a tumour, as well as exogenous drug administration. Drugs can cause endocrine abnormalities via different mechanisms, including direct alteration of hormone production, changes in the regulation of the hormonal axis, effects on hormonal transport, binding, and signalling, as well as similar changes to counter-regulatory hormone systems. Furthermore, drugs can affect the evaluation of endocrine parameters by causing interference with diagnostic tests. Common drug-induced endocrine and metabolic disorders include disorders of carbohydrate metabolism, electrolyte and calcium abnormalities, as well as drug-induced thyroid and gonadal disorders. An understanding of the proposed mechanisms of these drug effects and their evaluation and differential diagnosis may allow for more critical interpretation of the clinical observations associated with such disorders, better prediction of drug-induced adverse effects and better choices of and rationales for treatment.

Prehospital management of rapid atrial fibrillation: recommendations for treatment protocols

The present study was completed to establish an epidemiological database defining prehospital rapid atrial fibrillation (RAF) and interventions given such patients in the hope of developing recommendations for further treatment protocols. On review of 4,749 paramedic run reports from a low-volume urban emergency medical services (EMS) system, 33 persons (0.69%) presented with RAF. Data collected included vital signs/ventricular rate, patient age, ambulance field times, patient chief complaint, prehospital interventions, efficacy of interventions, additional cardiac rhythms, iatrogenic complications, and patient past medical history. Neither intravenous (IV) diltiazem or electrical cardioversion were used within the 12-month period of this study. Symptomatic/supportive care consisting of observation (72.73%) and interventions (27.27%) with nitroglycerine, furosemide, aspirin, morphine, and/or IV fluid bolus therapy accounted for all prehospital treatment. Paramedics documented improvement in 100% of patients. No cases occurred in which RAF resulted in severe hemodynamic instability. No inappropriate use, point estimate (PE) [(0)/(33) (0.00% to 10.60%)], or unmet need, PE [(0)/(4,716) (0.00% to 0.08%)] of care was noted. The data presented in this study suggest that given similar EMS system characteristics, prehospital RAF is an infrequently encountered, predominantly hemodynamically stable cardiac arrhythmia, readily treatable with symptomatic/supportive care, and cautious observation. The prehospital application of adult advanced cardiac life support guidelines utilizing IV diltiazem and electrical cardioversion for the treatment of RAF may be unnecessary.

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