Dihydropyridine (calcium channel blocker) overdose is one of the leading causes of death from cardiovascular drug poisoning. In contrast, angiotensin-II receptors blockers (ARBs) and angiotensin converting enzyme inhibitor (ACEIs) causes minimal toxicity in overdose. Frequently, these medications are co-ingested with dihydropridines. 

Recently, a retrospective study was conducted to evaluate the hemodynamic impact of  dihydropyridines with ARBs/ACEIs co-ingestion.

Results

Cohort

• 68 mixed overdoses of dihydropyridines with ARBs/ACEIs
• 21 single agent overdose (dihydropyridines)

Mixed overdose group had:

• Lower median nadir mean arterial pressure: 62 vs. 75 mmHg (p<0.001)
• Higher OR for hypotension: OR 4.5, (95% CI: 1.7 – 11.9)
• Higher OR for bradycardia: OR 8.8 (95% CI: 1.1 – 70) 
• Lower minimum systolic blood pressure by 11.5 mmHg (95% CI: 4.9 – 18.1)

Higher proportion of the mixed overdose group received:

• IV fluids: OR 5.7, (95% CI: 1.8-18.6)
• Antidotes and/or vasopressor: OR 2.9 (95% CI: 1.004 – 8.6)

Conclusion

Combined overdose of dihydropyridines with ARBs/ACEIs can result in more significant hypotension.

References

Huang J et al. Angiotensin axis antagonists increase the incidence of haemodynamic instability in dihydropyridine calcium channel blocker poisoning. Clint Toxicol (Phila) 2020. Epub. https://doi.org/10.1080/15563650.2020.1826504