From the FDA Drug Label
Missed Doses and Re-initiating Treatment: Inform patients and caregivers that if the patient misses taking clozapine for more than 2 days, they should not restart their medication at the same dosage but should contact their physician for dosing instructions [see Dosage and Administration (2.5), Warnings and Precautions (5.1,5. 3)].
The patient missed only one dose, which is less than 2 days. Therefore, the next dose can be 350mg. However, it is always best to consult the physician for dosing instructions if there are any concerns. 1
From the Research
If a patient misses a single dose of clozapine 350mg taken at night, they should take their regular 350mg dose at the next scheduled time and continue their normal dosing schedule. This approach is based on the understanding that clozapine is a potent antipsychotic with a narrow therapeutic window, and doubling the dose could lead to serious side effects including severe sedation, hypotension, seizures, or cardiac complications 2. The provided evidence does not directly address the issue of missing a dose, but it emphasizes the importance of careful management and monitoring of patients on clozapine due to its potential side effects 3, 4, 5, 6, 2. Key considerations include:
- The risk of agranulocytosis, which necessitates regular blood work and monitoring 3, 2.
- The potential for other serious side effects, such as seizures, myocarditis, and cardiomyopathy, which may require discontinuation of clozapine 2.
- The importance of maintaining therapeutic plasma levels, which is crucial for the drug's efficacy and safety 4. Given these considerations, it is crucial to prioritize caution and maintain the regular dosing schedule to minimize the risk of adverse effects while ensuring the patient continues to receive the therapeutic benefits of clozapine. If a patient has missed multiple doses (typically 48 hours or more), they should contact their healthcare provider immediately as they may need dose adjustment or monitoring when restarting, as tolerance to some side effects can be lost quickly. Patients on clozapine should always be enrolled in a monitoring program and maintain regular blood work regardless of missed doses, underscoring the need for vigilant management of this medication 2.