GANAXOLONE Drug Interactions: What You Need to Know

INTERACTIONS UGT inhibitors may increase ganaxolone exposures; consider reduction of a stable ZTALMY dosage when initiating a UGT inhibitor. ( 7.1 ) Cytochrome P450 inducers will decrease ganaxolone exposure. It is recommended to avoid concomitant use with strong or moderate CYP3A4 inducers; if unavoidable, consider a dosage increase of ZTALMY, but do not exceed the maximum recommended dosage. ( 7.2 )

7.1 Effect of UGT Inhibitors on ZTALMY Concomitant use of ZTALMY and UGT inhibitors (e.g., valproic acid) may increase the exposure of ganaxolone, which may increase the risk of ZTALMY associated adverse reactions in patients who have titrated to a stable ZTALMY dosage. Consider a reduction of ZTALMY maintenance dosage when initiating a UGT inhibitor <span class="opacity-50 text-xs">[see Clinical Pharmacology (12.3) ]</span>.

7.2 Effect of Strong or Moderate Cytochrome P450 Inducers on ZTALMY Coadministration of ZTALMY with CYP450 inducers, such as strong or moderate CYP3A4 inducers, will decrease ganaxolone exposure, which can lower the efficacy of ZTALMY <span class="opacity-50 text-xs">[see Clinical Pharmacology (12.3) ]</span> . It is recommended to avoid concomitant use of strong or moderate CYP3A4 inducers with ZTALMY. When concomitant use of strong or moderate CYP3A4 inducers is unavoidable, consider an increase in the dosage of ZTALMY; however, do not exceed the maximum daily dosage of ZTALMY <span class="opacity-50 text-xs">[see Dosage and Administration (2.1) ]</span> . In patients on a stable ZTALMY dosage who are initiating or increasing the dosages of enzyme-inducing antiepileptic drugs (e.g., carbamazepine, phenytoin, phenobarbital, and primidone), the ZTALMY dosage may need to be increased; however, do not exceed the maximum daily dosage of ZTALMY <span class="opacity-50 text-xs">[see Dosage and Administration (2.1) ]</span> .

7.3 Concomitant Use of ZTALMY with CNS Depressants and Alcohol Concomitant use of ZTALMY with CNS depressants, including alcohol, may increase the risk of somnolence and sedation <span class="opacity-50 text-xs">[see Warnings and Precautions (5.1) ]</span> .

None. None. ( 4 )

AND PRECAUTIONS Somnolence and Sedation: Monitor for somnolence and sedation and advise patients not to drive or operate machinery until they have gained sufficient experience with ZTALMY. Concomitant use with other CNS depressants or alcohol could potentiate adverse effects. ( 5.1 )

Suicidal

Behavior and Ideation: Monitor patients for suicidal behavior and thoughts. ( 5.2 ) Withdrawal of Antiepileptic Drugs: ZTALMY should be withdrawn gradually to minimize the risk of increased seizure frequency and status epilepticus. ( 5.3 )

5.1 Somnolence and Sedation ZTALMY can cause somnolence and sedation.

In Study

1 [see Clinical Studies (14) ] , the incidence of somnolence and sedation was 44% in patients treated with ZTALMY, compared with 24% in patients receiving placebo. Somnolence and sedation appeared early during treatment and were generally dose-related [see Adverse Reactions (6.1) ] . Other central nervous system (CNS) depressants, including opioids, antidepressants, and alcohol, could potentiate somnolence and sedation in patients receiving ZTALMY [see Clinical Pharmacology (12.3) ] . Prescribers should monitor patients for somnolence and sedation, and advise patients not to drive or operate machinery until they have gained sufficient experience on ZTALMY to gauge whether it adversely affects their ability to drive or operate machinery.

5.2 Suicidal Behavior and Ideation Antiepileptic drugs (AEDs), including ZTALMY, increase the risk of suicidal thoughts or behavior in patients taking these drugs for any indication. Patients treated with an AED for any indication should be monitored for the emergence or worsening of depression, suicidal thoughts or behavior, or any unusual changes in mood or behavior. Pooled analyses of 199 placebo-controlled clinical trials (mono- and adjunctive therapy) of 11 different AEDs, that did not include ZTALMY, showed that patients randomized to one of the AEDs had approximately twice the risk (adjusted Relative Risk 1.8, 95% CI:1.2, 2.7) of suicidal thinking or behavior compared to patients randomized to placebo. In these trials, which had a median treatment duration of 12 weeks, the estimated incidence rate of suicidal behavior or ideation among 27,863 AED-treated patients was 0.43%, compared to 0.24% among 16,029 placebo-treated patients, representing an increase of approximately one case of suicidal thinking or behavior for every 530 patients treated. There were 4 suicides in drug-treated patients in the trials and none in placebo-treated patients, but the number is too small to allow any conclusion about drug effect on suicide. The increased risk of suicidal thoughts or behavior with AEDs was observed as early as 1 week after starting drug treatment with AEDs and persisted for the duration of treatment assessed. Because most trials included in the analysis did not extend beyond 24 weeks, the risk of suicidal thoughts or behavior beyond 24 weeks could not be assessed. The risk of suicidal thoughts or behavior was generally consistent among drugs in the data analyzed. The finding of increased risk with AEDs of varying mechanisms of action and across a range of indications suggests that the risk applies to all AEDs used for any indication. The risk did not vary substantially by age (5–100 years) in the clinical trials analyzed.

Table

5 shows absolute and relative risk by indication for all evaluated AEDs.

Table

5 Risk of Suicidal Thoughts or Behaviors by Indication for Antiepileptic Drugs in the Pooled Analysis Indication Placebo Patients with Events per 1000 Patients Drug Patients with Events per 1000 Patients Relative Risk: Incidence of Events in Drug Patients/ Incidence in Placebo Patients Risk Difference: Additional Drug Patients with Events per 1000 Patients Epilepsy 1.0 3.4 3.5

2.4 Psychiatric 5.7 8.5 1.5

2.9 Other 1.0 1.8 1.9

0.9 Total 2.4 4.3 1.8

1.9 The relative risk for suicidal thoughts or behavior was higher in clinical trials in patients with epilepsy than in clinical trials in patients with psychiatric or other conditions, but the absolute risk differences were similar for the epilepsy and psychiatric indications. Anyone considering prescribing ZTALMY, or any other AED must balance the risk of suicidal thoughts or behaviors with the risk of untreated illness. Epilepsy and many other illnesses for which AEDs are prescribed are themselves associated with morbidity and mortality and an increased risk of suicidal thoughts and behavior. Should suicidal thoughts and behavior emerge during treatment, consider whether the emergence of these symptoms in any given patient may be related to the illness being treated.

5.3 Withdrawal of Antiepileptic Drugs As with most AEDs, ZTALMY should be withdrawn gradually because of the risk of increased seizure frequency and status epilepticus <span class="opacity-50 text-xs">[see Dosage and Administration (2.4) ]</span> . If withdrawal is needed because of a serious adverse event, rapid discontinuation can be considered.