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

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What each label says about the other drug

Provigil (modafinil tablets) is a Schedule IV wakefulness drug approved for excessive sleepiness in narcolepsy, obstructive sleep apnea and shift work disorder. In sleep apnea it treats the sleepiness, not the airway obstruction, and the label says a maximal effort to treat with CPAP should be made before and during treatment [1]. Its drug interactions section covers four things: CYP3A4/5 substrates (steroidal contraceptives, cyclosporine, midazolam, triazolam), CYP2C19 substrates (phenytoin, diazepam, propranolol, omeprazole, clomipramine), warfarin, and MAO inhibitors [1]. Testosterone is not named.

The Depo-Testosterone label for intramuscular testosterone cypionate lists oral anticoagulants, oxyphenbutazone, and the blood-glucose effect that matters for diabetes medicines in its interactions section [2]. Modafinil is not named.

Neither label lists the other drug as a contraindication. Provigil's only contraindication is hypersensitivity to modafinil or armodafinil or their inactive ingredients [1]. Depo-Testosterone's are hypersensitivity, breast carcinoma in men, known or suspected prostate carcinoma in men, pregnancy in women, and serious cardiac, hepatic or renal disease [2].

Why enzyme induction gets raised

The Provigil label states that clearance of CYP3A4/5 substrates may be increased through induction of metabolic enzymes, lowering their systemic exposure, and that dose adjustment of those drugs should be considered [1]. The substrates it names are steroidal contraceptives, cyclosporine, midazolam and triazolam; testosterone is not among them [1].

The Depo-Testosterone label says inactivation of testosterone occurs primarily in the liver, with metabolism to 17-keto steroids through two different pathways [2].

The birth-control warning does not carry over

The Provigil label says the effectiveness of steroidal contraceptives such as ethinyl estradiol may be reduced while taking modafinil and for one month after stopping, and recommends alternative or concomitant methods of contraception during that period [1]. Testosterone injections are not contraceptives and are not part of that warning.

Blood pressure: the overlap that is documented

Provigil's pooled placebo-controlled trials (934 patients on modafinil, 567 on placebo) reported hypertension in 3% vs 1% and palpitation in 2% vs 1% [1]. A larger share of modafinil patients needed new or increased antihypertensive medicine: 2.4% vs 0.7% overall, and 3.4% vs 1.1% in the sleep apnea studies [1]. The label also calls for increased monitoring in patients with known cardiovascular disease [1].

On the testosterone side, FDA's February 2025 class-wide labeling action states that completed ambulatory blood pressure studies confirmed a blood pressure increase with all testosterone products, class-wide [3]. The Depo-Testosterone label says testosterone can increase blood pressure, which can increase cardiovascular risk over time; that blood pressure should be monitored periodically, especially in men with hypertension; and that testosterone products are not recommended in uncontrolled hypertension [2].

Hematocrit: the monitoring comes from testosterone

A network meta-analysis of 29 placebo-controlled trials (3,393 men) found that every testosterone formulation raised mean hematocrit versus placebo: intramuscular enanthate and cypionate by 4.0% (95% CI 2.9 to 5.1), gel by 3.0%, and patch by 1.4% [4]. A retrospective review of 178 hypogonadal men found erythrocytosis (hematocrit above 50%) in 66.7% of those on injectable testosterone, 12.8% on gels and 35.1% on pellets; that study was not randomized, and the injection group was younger with a higher baseline hematocrit [5]. Another review put the risk of erythrocytosis (hematocrit above 0.52) at 315% higher than in controls [6]. The European Academy of Andrology guidelines treat a hematocrit above 48% to 50% as a relative contraindication to testosterone therapy [7], and the Endocrine Society recommends monitoring hematocrit in the first year [8].

Erythrocytosis and polycythemia do not appear in Provigil's table of adverse reactions. That table lists eosinophilia at 1% versus 0% on placebo, and the hematologic reaction named in the postmarketing section is agranulocytosis [1].

Warfarin: both labels give instructions

Each label speaks separately about warfarin. Modafinil: more frequent monitoring of prothrombin time and INR should be considered when it is coadministered with warfarin [1]. Testosterone cypionate: androgens may increase sensitivity to oral anticoagulants, the anticoagulant dose may need to be reduced, and INR and prothrombin time should be monitored more often when testosterone is started or stopped [2]. Both are instructions for warfarin plus each individual drug, not for modafinil plus testosterone.

Sleep apnea sits underneath both prescriptions

For obstructive sleep apnea, Provigil treats excessive sleepiness rather than the underlying obstruction [1]. Separately, the Endocrine Society guideline recommends against starting testosterone therapy in men with untreated severe sleep apnea [8].

Standing label warnings for each drug

Provigil has no boxed warning but carries serious skin and hypersensitivity warnings. The label says to stop at the first sign of rash unless it is clearly not drug-related; nearly all serious cases occurred within 1 to 5 weeks of starting, and stopping may not prevent a rash from becoming life-threatening or disfiguring [1]. The Depo-Testosterone label says to evaluate leg pain, swelling, warmth and redness for deep vein thrombosis and acute shortness of breath for pulmonary embolism, and to discontinue if a venous thromboembolic event is suspected [2]. These are the labels' warnings for each drug on its own; they do not describe a combined effect.