Massive diltiazem overdose

Extracorporeal treatment for calcium channel blocker poisoning: systematic review and recommendations from the EXTRIP workgroup

BACKGROUND

Calcium channel blockers (CCBs) are commonly used to treat conditions such as arterial hypertension and supraventricular dysrhythmias. Poisoning from these drugs can lead to severe morbidity and mortality. We aimed to determine the utility of extracorporeal treatments (ECTRs) in the management of CCB poisoning.

METHODS

We conducted systematic reviews of the literature, screened studies, extracted data, summarized findings, and formulated recommendations following published EXTRIP methods.

RESULTS

A total of 83 publications (6 in vitro and 1 animal experiments, 55 case reports or case series, 19 pharmacokinetic studies, 1 cohort study and 1 systematic review) met inclusion criteria regarding the effect of ECTR. Toxicokinetic or pharmacokinetic data were available on 210 patients (including 32 for amlodipine, 20 for diltiazem, and 52 for verapamil). Regardless of the ECTR used, amlodipine, bepridil, diltiazem, felodipine, isradipine, mibefradil, nifedipine, nisoldipine, and verapamil were considered not dialyzable, with variable levels of evidence, while no dialyzability grading was possible for nicardipine and nitrendipine. Data were available for clinical analysis on 78 CCB poisoned patients (including 32 patients for amlodipine, 16 for diltiazem, and 23 for verapamil). Standard care (including high dose insulin euglycemic therapy) was not systematically administered. Clinical data did not suggest an improvement in outcomes with ECTR. Consequently, the EXTRIP workgroup recommends against using ECTR in addition to standard care for patients severely poisoned with either amlodipine, diltiazem or verapamil (strong recommendations, very low quality of the evidence (1D)). There were insufficient clinical data to draft recommendation for other CCBs, although the workgroup acknowledged the low dialyzability from, and lack of biological plausibility for, ECTR.

CONCLUSIONS

Both dialyzability and clinical data do not support a clinical benefit from ECTRs for CCB poisoning. The EXTRIP workgroup recommends against using extracorporeal methods to enhance the elimination of amlodipine, diltiazem, and verapamil in patients with severe poisoning.

Calcium Channel Blocker Ingestion: An Evidence-Based Consensus Guideline for Out-of-Hospital Management

In 2003, U.S. poison control centers were consulted after 9650 ingestions of calcium channel blockers (CCBs), including 57 deaths. This represents more than one-third of the deaths reported to the American Association of Poison Control Centers' Toxic Exposure Surveillance System database that were associated with cardiovascular drugs and emphasizes the importance of developing a guideline for the out-of-hospital management of calcium channel blocker poisoning. The objective of this guideline is to assist poison center personnel in the appropriate out-of-hospital triage and initial management of patients with suspected ingestions of calcium channel blockers. An evidence-based expert consensus process was used to create this guideline. This guideline applies to ingestion of calcium channel blockers alone and 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. The panel's recommendations follow. The grade of recommendation is in parentheses. 1) All patients with stated or suspected self-harm or the recipient of a potentially malicious administration of a CCB should be referred to an emergency department immediately regardless of the amount ingested (Grade D). 2) Asymptomatic patients are unlikely to develop symptoms if the interval between the ingestion and the call is greater than 6 hours for immediate-release products, 18 hours for modified-release products other than verapamil, and 24 hours for modified-release verapamil. These patients do not need referral or prolonged observation (Grade D). 3) Patients without evidence of self-harm should have further evaluation, including determination of the precise dose ingested, history of other medical conditions, and the presence of co-ingestants. Ingestion of either an amount that exceeds the usual maximum single therapeutic dose or an amount equal to or greater than the lowest reported toxic dose, whichever is lower (see Table 5), would warrant consideration of referral to an emergency department (Grade D). 4) Do not induce emesis (Grade D). 5) Consider the administration of activated charcoal orally if available and no contraindications are present. However, do not delay transportation in order to administer charcoal (Grade D). 6) For patients who merit evaluation in an emergency department, ambulance transportation is recommended because of the potential for life-threatening complications. Provide usual supportive care en route to the hospital, including intravenous fluids for hypotension. Consider use of intravenous calcium, glucagon, and epinephrine for severe hypotension during transport, if available (Grade D). 7) Depending on the specific circumstances, follow-up calls should be made to determine outcome at appropriate intervals based on the clinical judgment of the poison center staff (Grade D).

Lessons learnt in the pharmacokinetic analysis of the effect of haemoperfusion for acute overdose with sustained-release diltiazem

The effect of charcoal haemoperfusion on the pharmacokinetics of diltiazem is described in a patient with severe clinical toxicity following acute overdose. The patient presented within 3 h following acute ingestion of multiple medications including sustained-release diltiazem. Routine resuscitation and supportive care were administered, but hypotension did not resolve despite intravenous fluids and infusions of calcium, adrenaline, noradrenaline and vasopressin. Multiple-doses of activated charcoal, haemodialysis and charcoal haemoperfusion were prescribed to expedite the elimination of diltiazem. The maximum diltiazem concentration (577 microg.l(-1)) was recorded 7 h post ingestion which was followed by an erratic and prolonged elimination phase. The maximum clearance of diltiazem due to haemoperfusion was calculated to be 19.4 and 15.1 ml.min(-1) at different times, equating to removal of approximately 1.5 mg diltiazem during 4 h of haemoperfusion. Haemoperfusion did not appear to remove sufficient diltiazem to recommend its routine use in the treatment of patients with acute diltiazem overdose.

Easily reversible hypoxemia and hypotension induced by nimodipine

Calcium antagonists are drugs commonly prescribed for the treatment of hypertension, angina pectoris, cardiac arrhythmias and other disorders because of their efficacy and tolerability. Nevertheless, overdosage and intoxication are well documented. In this paper we report a case of nimodipine overdosage resulting in prolonged hypotension and hypoxemia, which was successfully treated with calcium gluconate.

Massive diltiazem overdose treated with extracorporeal membrane oxygenation

OBJECTIVE

To describe a case of massive diltiazem overdose with a good outcome achieved after early and aggressive supportive therapy.

DESIGN

Case report.

SETTING

Pediatric Critical Care Unit.

PATIENT

Sixteen-year-old adolescent girl.

MEASUREMENTS AND MAIN RESULTS

A 16-yr-old adolescent girl presented to the emergency department 6 hrs after the intentional ingestion of 40 300-mg sustained-release diltiazem tablets (12 g of Cardura CD). She was hypotensive and required a glucagon and epinephrine infusion despite initial fluid resuscitation with saline and intravenous calcium (1 g). Multiple asystolic cardiac arrests ensued which became increasingly refractory to high-dose epinephrine. Hemodynamic support was achieved with a 48-hr period of extracorporeal membrane oxygenation for atrial standstill. Severe multiorgan dysfunction ensued (cardiac, neurologic, renal, hepatic, gastrointestinal, hematologic, and metabolic). Plasma diltiazem and its metabolites were measured and its half-life was reported between 28 and 48 hrs. A sustained decline in plasma diltiazem levels and its metabolites was not observed after two periods of charcoal hemoperfusion. Recovery of organ function occurred with sinus rhythm noted on the ninth day. The patient made a full recovery and was discharged from the critical care unit after 15 days.

CONCLUSIONS

Although massive calcium channel blocker overdose can produce profound and prolonged cardiac or multiorgan dysfunction, its toxic effects may be reversible. Supportive therapy, particularly of the cardiovascular system, is the most important goal.

Severe atenolol and diltiazem overdose

CASE REPORT

A case of combined, massive overdose of both atenolol and diltiazem in an adult male is reported. Cardiac arrest ensued which was responsive to cardiopulmonary resuscitation. Bradycardia, hypotension, and oliguria followed which were resistant to intravenous pacing and multiple pharmacologic interventions, including intravenous fluids, calcium, dopamine, dobutamine, epinephrine, prenalterol, and glucagon. Adequate mean arterial pressure and urine output were restored only after addition of phenylephrine to therapy with multiple agents and transvenous pacing. The patient survived until discharge after a hospital course complicated by nontransmural myocardial infarct on hospital day 4 and pneumonia. Laboratory testing subsequently revealed high serum levels of both atenolol and diltiazem. The atenolol level of 35 microg/mL in this patient is the highest reported associated with survival.

CONCLUSION

This case illustrates severe cardiovascular toxicity after overdose of both atenolol and diltiazem. Oliguria, which has previously been reported in severe atenolol overdose, was successfully treated without hemodialysis by the addition of phenylephrine to aggressive therapy with pacing, inotropic, and pressor support.

Pharmacokinetics of diltiazem in massive overdose

Several cases of poisoning with diltiazem have been described in the literature, but information about the pharmacokinetics of diltiazem in overdose is sparse. The authors report pharmacokinetic and clinical observations in a patient who ingested 7.2 g of slow-release dilitiazem. Grave, persistent hypotension was the overriding clinical manifestation, but the patient eventually survived with aggressive cardiovascular support. No serious conduction abnormalities were seen. Blood samples were taken repeatedly for 2-3 days for analysis of serum diltiazem and desacetyldiltiazem and desacetyldiltiazem concentrations. The serum diltiazem concentration measured in the first sample taken (16.5 h postingestion), 3,171 ng/ml, is one of the highest concentrations reported in a patient who survived. The half-life was 13.3 h for diltiazem and 10.5 h for desacetyldiltiazem. Charcoal hemoperfusion had no apparent effect on the elimination of either compound. The relatively long half-life of diltiazem may have resulted from rate-limiting absorption and probably does not indicate saturation of diltiazem metabolism. The patient was discharged with no apparent neurological or cardiological deficits.

Massive Overdose of Cardizem CD

Long-acting diltiazem preparations are currently frequently prescribed, and the potential for serious morbidity and mortality with an overdose can be significant. We present a case of Cardizem CD overdose in which a 22-year-old patient ingested 18.0 g, in an apparent suicide attempt. She presented within 5 hours of ingestion with a blood pressure of 80/30 mm Hg and a pulse of 80 beats/minute. Interventions included intravenous fluids, activated charcoal, atropine, calcium, dopamine, norepinephrine, glucagon, bowel irrigation with polyethylene glycol, and placement of a temporary transvenous pacemaker. Diltiazem levels were obtained, and an elimination half-life was calculated. Unique side effects of this overdose are discussed, and a treatment approach is suggested. Early and aggressive treatment is essential, and preparation for anticipated side effects should be initiated as soon as possible.