Angiotensin axis antagonists increase the incidence of haemodynamic instability in dihydropyridine calcium channel blocker poisoning

Unique Case of Cardiogenic Shock in the Setting of Cumulative Calcium Channel Blocker Toxicity

Calcium channel blockers (CCBs) are the most prescribed medications in clinical practice. These drugs treat many conditions, including migraine headaches, vasospasms, abnormal heart rhythms, and hypertension. This widespread use, however, has also been linked with the increased incidence of CCB toxicity cases. CCB toxicity may be from accidental ingestion or iatrogenic. Patients may show signs of cardiovascular toxicity such as hypotension, bradyarrhythmia, coma, or even death. The treatment includes discontinuing the offending medication, securing the airway, and raising blood pressure. Herein, we report a rare case of a 40-year-old male with a history of uncontrolled hypertension and advanced kidney disease who experienced iatrogenic cumulative calcium channel blocker toxicity while switching CCB classes due to a hypertensive emergency with concomitant atrial flutter. Although uncommon in clinical practice, iatrogenic CCB toxicity is possible and equally lethal. Clinicians must be cautious when initiating these drugs, switching between oral and intravenous formulations, or switching from one class to another to avoid overdoses.

Intoxication with massive doses of amlodipine and candesartan requiring venoarterial extracorporeal membrane oxygenation

Background

Calcium channel blockers and angiotensin II receptor blockers are commonly prescribed to treat hypertension. Massive overdoses can cause both distributive and cardiogenic shock because of their effects on vascular smooth muscles and severe myocardial depression.

Case Presentation

We present the case of a 46-year-old man who was brought to our emergency department after ingesting 1210 mg amlodipine and 936 mg candesartan. The patient's hemodynamic status deteriorated despite treatment with vasopressors, calcium gluconate, and hyperinsulinemia-euglycemia therapy with mechanical ventilation. Venoarterial extracorporeal membrane oxygenation was initiated for refractory shock. The patient was weaned off extracorporeal membrane oxygenation on day 5 and discharged on day 18 of hospitalization.

Conclusion

When medical therapies are ineffective, aggressive venoarterial extracorporeal membrane oxygenation should be considered for the management of refractory shock in the setting of calcium channel blocker with angiotensin II receptor blocker overdose.

The Role of Angiotensin II in Poisoning-Induced Shock-a Review

Background

Shock in drug poisoning is a life-threatening condition and current management involves fluid resuscitation and vasopressor therapy. Management is limited by the toxicity of high-dose vasopressors such as catecholamines. Clinical trials have shown the efficacy of angiotensin II as an adjunct vasopressor in septic shock. The aim of this review is to assess the use of angiotensin II in patients with shock secondary to drug overdose.

Methods

Medline (from 1946), Embase (from 1947) and PubMed (from 1946) databases were searched until July 2021 via OVID. Included studies were those with shock due to drug poisoning and received angiotensin II as part of their treatment regimen. Of the 481 articles identified, 13 studies (case reports and scientific abstracts) were included in the final analysis with a total of 14 patients. Extracted data included demographics, overdose drug and dosage, angiotensin II dosage, time of angiotensin II administration, haemodynamic changes, length of hospital stay, mortality, complications, cardiac function and other treatment agents used.

Results

Thirteen studies were included consisting of 6 case reports, 6 scientific abstracts and 1 case series. Overdose drugs included antihypertensives (n = 8), psychotropics (n = 4), isopropanol (n = 1) and tamsulosin (n = 1). Out of a total of 14 patients, 3 patients died. Ten patients had their haemodynamic changes reported. In terms of MAP or SBP changes, three patients (30%) had an immediate response to angiotensin II, four patients (40%) had responses within 30 min, one patient (10%) within two hours and two patients (20%) did not have their time reported. Two patients were shown to have direct chronotropic effects within 30 min of angiotensin II administration. The median hospital stay for patients was 5 days (IQR = 4). The time from overdose until angiotensin II administration ranged from 5 to 56 h. Other vasopressors used included phenylephrine, noradrenaline, adrenaline, vasopressin, dobutamine, dopamine, methylene blue and ephedrine. A median of 3 vasopressors were used before initiation of angiotensin II. Twelve patients received angiotensin II as their final treatment.

Conclusions

Angiotensin II may be useful as an adjunct vasopressor in treating shock secondary to drug poisoning. However, the current literature consisted of only very low-quality studies. To truly assess the utility of angiotensin II use in drug-induced poisoned patients, further well-designed prospective studies are required.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13181-022-00885-4.

Quantitative Estimation of the Hydrogen-Atom-Donating Ability of 4-Substituted Hantzsch Ester Radical Cations

The purpose of this study is to investigate thermodynamic and kinetic properties on the hydrogen-atom-donating ability of 4-substituted Hantzsch ester radical cations (XRH•+), which are excellent NADH coenzyme models. Gibbs free energy changes and activation free energies of 17 XRH•+ releasing H• [denoted as ΔG HD o(XRH•+) and ΔG HD ≠(XRH•+)] were calculated using density functional theory (DFT) and compared with that of Hantzsch ester (HEH2) and NADH. ΔG HD o(XRH•+) range from 19.35 to 31.25 kcal/mol, significantly lower than that of common antioxidants (such as ascorbic acid, BHT, the NADH coenzyme, and so forth). ΔG HD ≠(XRH•+) range from 29.81 to 39.00 kcal/mol, indicating that XRH•+ spontaneously releasing H• are extremely slow unless catalysts or active intermediate radicals exist. According to the computed data, it can be inferred that the Gibbs free energies and activation free energies of the core 1,4-dihydropyridine radical cation structure (DPH•+) releasing H• [ΔG HD o(DPH•+) and ΔG HD ≠(DPH•+)] should be 19-32 kcal/mol and 29-39 kcal/mol in acetonitrile, respectively. The correlations between the thermodynamic driving force [ΔG HD o(XRH•+)] and the activation free energy [ΔG HD ≠(XRH•+)] are also explored. Gibbs free energy is the important and decisive parameter, and ΔG HD ≠(XRH•+) increases in company with the increase of ΔG HD o(XRH•+), but no simple linear correlations are found. Even though all XRH•+ are judged as excellent antioxidants from the thermodynamic view, the computed data indicate that whether XRH•+ is an excellent antioxidant in reaction is decided by the R substituents in 4-position. XRH•+ with nonaromatic substituents tend to release R• instead of H• to quench radicals. XRH•+ with aromatic substituents tend to release H• and be used as antioxidants, but not all aromatic substituted Hantzsch esters are excellent antioxidants.