Effect of Ranolazine on White Blood Cell Count
Based on the available evidence, ranolazine (Ranexa) does not appear to have any significant effect on white blood cell (WBC) count.
Pharmacological Profile of Ranolazine
Ranolazine is a piperazine derivative approved for the treatment of chronic stable angina pectoris. Its mechanism of action differs from traditional anti-anginal medications:
- Acts primarily by inhibiting the late inward sodium current, reducing calcium overload and left ventricular diastolic tension 1
- Does not exert its anti-anginal effects through changes in heart rate or blood pressure 1, 2
- Is extensively metabolized by cytochrome P450 (CYP) 3A enzymes and to a lesser extent by CYP2D6 1
- Has an elimination half-life of approximately 7 hours for the extended-release formulation 1
Hematologic Safety Profile
The available evidence does not indicate that ranolazine has any significant effect on white blood cell count:
- None of the clinical pharmacokinetic studies of ranolazine report effects on WBC count as an adverse effect 1, 3, 2
- Unlike medications such as azathioprine or cyclophosphamide that are known to affect WBC counts 4, ranolazine is not mentioned in any guidelines as having hematologic toxicity
Medications Known to Affect WBC Count
For context, several medications are known to affect WBC counts:
- Azathioprine and cyclophosphamide require monitoring of WBC counts, with dose adjustments needed if WBC decreases to <4,000/mm³ 5
- Clozapine requires regular WBC monitoring due to risk of agranulocytosis 6
- Corticosteroids typically cause an increase in WBC count, with mean increases of up to 4.84 × 10⁹/L within 48 hours after high-dose administration 7
Clinical Implications
When managing patients on ranolazine:
- Routine monitoring of WBC count is not required specifically for ranolazine therapy
- If abnormal WBC counts are observed in patients taking ranolazine, clinicians should consider other causes or concomitant medications
- Unlike medications such as azathioprine or clozapine, there are no established protocols for WBC monitoring with ranolazine therapy
Conclusion
Ranolazine appears to have a favorable hematologic safety profile with no documented effects on WBC count based on available evidence. Any significant changes in WBC count observed in patients taking ranolazine should prompt investigation for other causes rather than being attributed to ranolazine itself.