Belsomra and Testosterone Interaction: What Patients and Clinicians Need to Know

Is there a known interaction between Belsomra and testosterone?

The Belsomra prescribing information has a drug interactions section that covers strong CYP3A inhibitors, moderate CYP3A inhibitors, strong CYP3A inducers, digoxin and CNS-active agents such as alcohol [1]. Testosterone is not named among the examples of strong or moderate CYP3A inhibitors, and the label gives no testosterone-specific dose change for the pair [1].

The label's examples of moderate CYP3A inhibitors include diltiazem, verapamil, fluconazole, erythromycin, ciprofloxacin, aprepitant and grapefruit juice [1]. With these, the label sets the recommended Belsomra dose at 5 mg [1].

What the Belsomra label says about CYP3A

CYP3A is the major elimination pathway for suvorexant [1]. The label says concomitant use with strong CYP3A inhibitors such as ketoconazole, itraconazole, clarithromycin or ritonavir is not recommended [1]. With moderate CYP3A inhibitors, the recommended dose is 5 mg, generally not above 10 mg [1].

The usual Belsomra dose is 10 mg once nightly, taken within 30 minutes of bed with at least 7 hours left before planned awakening; the maximum is 20 mg once nightly [1]. The mean half-life is about 12 hours [1].

What testosterone adds that matters alongside a sleep drug

Testosterone products can raise blood pressure. FDA says ambulatory blood pressure studies confirmed an increase with all testosterone products, class-wide [5]. The Depo-Testosterone label says testosterone can increase blood pressure, which can increase cardiovascular risk over time, and that testosterone products are not recommended in men with uncontrolled hypertension [2].

Testosterone can also raise hematocrit. The Depo-Testosterone label lists polycythemia as an adverse reaction and advises checking hemoglobin and hematocrit periodically during long-term use [2]. A network meta-analysis of 29 placebo-controlled trials in 3,393 men found that intramuscular testosterone enanthate or cypionate raised mean hematocrit by 4.0% versus placebo [6]. That is a testosterone effect, not a suvorexant effect.

Sleep apnea is the other overlap. The Endocrine Society guideline recommends against starting testosterone in men with untreated severe sleep apnea [3]. The Belsomra label says the drug has not been studied in people with severe obstructive sleep apnea [1].

Next-day sedation and driving

Belsomra is a CNS depressant and can impair daytime wakefulness even when taken as prescribed [1]. In a study of healthy adults, driving ability was impaired in some people taking 20 mg [1]. The label cautions patients taking 20 mg about next-day driving and other activities needing full alertness, and says lower doses can also impair driving because people vary [1]. Alcohol added to psychomotor impairment in the label's interaction data [1].

Monitoring for each drug

For Belsomra, the label focuses on dose, timing, alcohol and next-day alertness [1]. For testosterone, the Depo-Testosterone label addresses blood pressure, hematocrit and prostate-related risks [2]. Neither label lists the other drug among its interactions [1][2].