Addyi and Rosuvastatin Interaction: What You Need to Know

What Is the Addyi and Rosuvastatin Interaction?

Flibanserin and rosuvastatin do not share a major metabolic pathway, which means a pharmacokinetic drug-drug interaction (DDI) driven by enzyme competition is unlikely at standard doses. Flibanserin is broken down primarily by CYP3A4 and, to a lesser extent, CYP2C19 in the liver. Rosuvastatin bypasses those enzymes almost entirely, relying instead on the organic anion transporting polypeptide (OATP) transporters OATP1B1 and OATP1B3 for hepatic uptake and on breast cancer resistance protein (BCRP) for efflux.

The FDA label for flibanserin identifies strong CYP3A4 inhibitors (e.g., ketoconazole, fluconazole, clarithromycin) and moderate CYP3A4 inhibitors (e.g., fluconazole at lower doses, grapefruit juice) as contraindicated or requiring caution. Rosuvastatin is not a CYP3A4 inhibitor, so that mechanism of harm does not apply here. [1]

Pharmacokinetic Profile of Flibanserin

Flibanserin reaches peak plasma concentration approximately 45 minutes after an oral bedtime dose of 100 mg. Its half-life is roughly 11 hours. CYP3A4 is responsible for the bulk of its hepatic clearance, with CYP2C19 contributing a secondary pathway. [2] Co-administration with a strong CYP3A4 inhibitor can raise flibanserin exposure by as much as 4.5-fold, which is why the FDA label carries a contraindication against that combination.

Flibanserin is also a weak inhibitor of CYP2C19 and P-glycoprotein (P-gp) at supratherapeutic concentrations. At the approved 100 mg bedtime dose, clinical inhibition of P-gp substrates has not been demonstrated to a degree that alters outcomes in registered trials.

Pharmacokinetic Profile of Rosuvastatin

Rosuvastatin is absorbed in the small intestine and taken up into hepatocytes via OATP1B1 and OATP1B3, the same transporters that handle many other statins. Approximately 10% of rosuvastatin undergoes CYP2C9-mediated metabolism; the rest is excreted unchanged. [3] BCRP-mediated efflux in the gut and liver also shapes rosuvastatin bioavailability significantly, which is why BCRP inhibitors such as cyclosporine can increase rosuvastatin AUC by up to 7-fold per the Crestor label. [4]

Flibanserin does not appear to meaningfully inhibit OATP1B1, OATP1B3, or BCRP at therapeutic concentrations. The Addyi prescribing information does not list rosuvastatin or other statins under known interactions.

Where a Theoretical Risk Exists

The weakest signal worth tracking is P-gp. Rosuvastatin is a mild P-gp substrate, and flibanserin shows weak P-gp inhibitory activity in vitro. In vitro studies suggest that clinically meaningful P-gp inhibition by flibanserin is unlikely at the 100 mg dose, but no published crossover pharmacokinetic study has specifically tested flibanserin 100 mg alongside rosuvastatin in a head-to-head design. [2] That absence of data is not the same as confirmed safety; it simply means the theoretical risk has not been definitively excluded by a dedicated clinical trial.

Severity Classification of This Interaction

Most clinical DDI databases (Lexicomp, Micromedex, Clinical Pharmacology) assign flibanserin-rosuvastatin a low-severity or "monitor" classification, reflecting the absence of a shared major metabolic enzyme and the lack of documented adverse event reports in the literature. This contrasts sharply with the flibanserin-fluconazole combination, which the FDA rates as contraindicated. [5]

How DDI Severity Is Graded

The FDA Guidance for Industry on drug interaction studies categorizes interactions by the degree of AUC change a perpetrator drug causes in a victim drug. An interaction producing a greater than 5-fold increase in victim AUC is "strong," 2-fold to 5-fold is "moderate," and less than 2-fold is "weak." [6] Rosuvastatin does not alter flibanserin's CYP3A4 clearance. Flibanserin does not substantially alter OATP-mediated uptake of rosuvastatin. Neither drug qualifies as a strong or moderate perpetrator for the other under this framework.

Pharmacodynamic Overlap

Flibanserin exerts its therapeutic effect through agonism at serotonin 1A (5-HT1A) receptors and antagonism at serotonin 2A (5-HT2A) receptors, with secondary dopamine D4 antagonism. Its CNS-active profile produces somnolence and dizziness as common adverse effects. In the pooled VIOLET/DAISY/BEGONIA trial dataset (N=2,955), somnolence occurred in 11% of flibanserin-treated women vs. 2% of placebo-treated women. [2]

Rosuvastatin has no CNS activity. It does not lower blood pressure. It does not potentiate sedation. The two drugs do not share a pharmacodynamic target, so additive or synergistic adverse effects are not expected on those axes.

Myopathy is the primary pharmacodynamic concern for any statin. Rosuvastatin-associated myopathy risk scales with plasma statin concentration, which in turn scales with OATP transporter function and BCRP activity. Because flibanserin does not appear to substantially alter either, the myopathy risk from rosuvastatin is not expected to change with co-administration.

Flibanserin's Full Interaction Profile: The Interactions That Actually Matter

Understanding the flibanserin-rosuvastatin pairing requires context from flibanserin's clinically significant interactions. These interactions are pharmacokinetically proven and FDA-labeled.

CYP3A4 Inhibitors (Contraindicated or Major)

Strong CYP3A4 inhibitors raise flibanserin AUC by 4- to 5-fold, producing extreme somnolence, hypotension, and syncope. The FDA label for Addyi lists the following as contraindicated: ketoconazole, itraconazole, posaconazole, clarithromycin, nefazodone, ritonavir, saquinavir, nelfinavir, indinavir, boceprevir, telaprevir, telithromycin, and conivaptan. [7] Moderate CYP3A4 inhibitors, including fluconazole, require caution and carry specific dosing guidance.

Rosuvastatin inhibits none of these enzymes. That is a key differentiator.

Alcohol (Black Box Warning)

The FDA placed a black box warning on Addyi for alcohol co-ingestion. [7] A pharmacodynamic interaction between flibanserin and alcohol causes symptomatic hypotension and syncope, with onset possible within 30 minutes of drinking. Women are counseled to abstain from alcohol entirely while taking flibanserin.

Rosuvastatin has no alcohol-interaction black box. This remains among the most practically important counseling points for any patient on flibanserin, regardless of what other drugs are co-prescribed.

CYP2C19 Inhibitors

Because CYP2C19 provides a secondary clearance route for flibanserin, inhibitors such as omeprazole, esomeprazole, and fluvoxamine may raise flibanserin levels modestly. The magnitude of this effect is smaller than with CYP3A4 inhibition. Rosuvastatin does not inhibit CYP2C19.

P-gp Inducers

Rifampin, a potent CYP3A4 and P-gp inducer, reduces flibanserin AUC by approximately 95%, effectively eliminating therapeutic exposure. [2] Women on rifampin-based regimens cannot achieve adequate flibanserin levels. Rosuvastatin is not a P-gp inducer, so this mechanism is not relevant to the combination discussed in this article.

Rosuvastatin's Full Interaction Profile: Key Comparators

Rosuvastatin interactions are driven almost entirely by OATP1B1/1B3 inhibitors, BCRP inhibitors, and a handful of CYP2C9-relevant drugs. These mechanisms are distinct from flibanserin's.

OATP Inhibitors and Rosuvastatin Exposure

Cyclosporine co-administration raises rosuvastatin AUC by approximately 7-fold by inhibiting OATP1B1/1B3 and BCRP simultaneously. [3] The rosuvastatin label caps the dose at 5 mg daily in patients receiving cyclosporine. Gemfibrozil inhibits OATP1B1 and CYP2C8, raising rosuvastatin AUC by roughly 2-fold per the FDA label data.

Flibanserin is not an OATP inhibitor. Women taking both drugs do not need rosuvastatin dose reduction on that basis.

Antacids and Rosuvastatin

Aluminum and magnesium hydroxide-containing antacids reduce rosuvastatin Cmax by approximately 54% when taken simultaneously. [1] Separating administration by at least 2 hours restores full exposure. This is unrelated to flibanserin.

Race and SLCO1B1/ABCG2 Genotype

Rosuvastatin plasma concentrations are approximately 2-fold higher in Asian patients compared to Caucasian patients, driven by polymorphisms in SLCO1B1 (encoding OATP1B1) and ABCG2 (encoding BCRP). The FDA label recommends initiating rosuvastatin at 5 mg daily in patients of Asian ancestry. [1] Flibanserin does not alter transporter genotype expression and does not modify this pharmacogenomic risk.

Clinical Monitoring When Co-Prescribing Both Drugs

Even with a low DDI severity rating, clinicians should follow a structured monitoring plan whenever flibanserin is added to an existing regimen that includes rosuvastatin, or vice versa.

Baseline Assessment Before Starting Flibanserin

Before initiating flibanserin in a woman already taking rosuvastatin, review the complete medication list for CYP3A4 inhibitors and alcohol use patterns first. Obtain a baseline blood pressure reading. The Addyi REMS program, as described on the FDA REMS database, requires prescribers to counsel patients specifically on hypotension and syncope risk, alcohol avoidance, and the hazard of operating machinery within 6 hours of the bedtime dose. [8]

Confirm the rosuvastatin dose. Doses of 20 mg to 40 mg are associated with higher myopathy rates than lower doses, so documenting baseline creatine kinase (CK) and muscle symptom status is reasonable practice before adding any new medication. The ACC/AHA 2018 Cholesterol Guideline recommends CK measurement when myopathy is suspected. [9]

First 4 Weeks on Combination Therapy

Ask about new or worsening dizziness, excessive daytime sleepiness, and episodes of near-syncope or syncope at the first follow-up. These are the adverse effects most likely to emerge from flibanserin regardless of rosuvastatin status, and catching them early prevents falls and injury. In the BRIGHT trial (N=1,543), dizziness occurred in 11.4% of flibanserin recipients. [10]

Ask about muscle pain, weakness, or dark urine at this same visit. While the flibanserin-rosuvastatin combination does not theoretically raise myopathy risk, patients who develop new musculoskeletal complaints after any medication change deserve prompt evaluation.

Ongoing Monitoring

Re-evaluate rosuvastatin tolerability at every annual lipid panel visit. If the patient is titrated upward on rosuvastatin (e.g., from 10 mg to 20 mg or 40 mg) while remaining on flibanserin, repeat the muscle symptom inquiry and consider a CK level if symptoms arise. The FDA safety communication on statin myopathy notes that risk increases with higher statin doses and drug interactions that raise statin plasma levels. [11]

Dose Adjustment Recommendations

No dose adjustment of rosuvastatin is required specifically because of flibanserin co-administration, based on the current pharmacokinetic profile of both drugs and available DDI data. [12]

No dose adjustment of flibanserin is required specifically because of rosuvastatin co-administration.

Flibanserin has only one approved dose, 100 mg at bedtime, and it cannot be titrated upward. If adverse effects (somnolence, hypotension) emerge during combination therapy, the clinician should first exclude other culprits on the medication list (CYP3A4 inhibitors, antihypertensives, CNS depressants) before attributing the event to the rosuvastatin combination.

If the patient's rosuvastatin dose needs to increase for cardiovascular risk reduction goals per the 2018 ACC/AHA cholesterol guideline's risk-based intensity thresholds, flibanserin co-administration alone is not a reason to delay that escalation. [9]

Patient Counseling Points for Women Taking Both Drugs

Clear counseling at the point of prescribing reduces adverse outcomes and improves adherence to both medications.

Timing and Alcohol

Take flibanserin at bedtime only, not in the morning or afternoon. Avoid alcohol completely while taking flibanserin; this is a black-box-level warning from the FDA, not a routine caution. Rosuvastatin is typically taken in the evening as well, but timing relative to flibanserin does not need to be separated.

Symptoms to Report Immediately

Any episode of fainting, feeling faint on standing, or sudden severe dizziness warrants same-day contact with the prescriber. These symptoms could reflect flibanserin-related hypotension, which is dose-independent and most pronounced within the first few hours after ingestion. Muscle pain that is new, severe, or accompanied by dark-colored urine warrants evaluation for statin-related myopathy, though this risk is not amplified by flibanserin.

Grapefruit and Supplement Interactions

Grapefruit juice is a moderate CYP3A4 inhibitor. Drinking grapefruit juice while taking flibanserin can raise flibanserin plasma concentrations, which increases sedation and hypotension risk. [7] Women taking both drugs should avoid grapefruit juice regardless of rosuvastatin status. St. John's Wort, a CYP3A4 inducer, reduces flibanserin exposure substantially and should be avoided.

What to Tell Your Pharmacist

Every pharmacy visit is an opportunity to reconcile the full medication list. Women should inform the pharmacist about flibanserin specifically, since it is a relatively infrequently dispensed drug and may not appear in all pharmacist DDI screening workflows. The FDA MedWatch program accepts voluntary adverse event reports; patients who experience unexpected symptoms while on both drugs can report directly.

Special Populations

Women With Hepatic Impairment

Flibanserin is contraindicated in patients with any degree of hepatic impairment per its FDA label. Because flibanserin depends heavily on hepatic CYP3A4 metabolism, impaired liver function raises plasma concentrations sharply. Rosuvastatin exposure is also increased by hepatic impairment due to reduced OATP-mediated clearance. [3] A woman with liver disease who requires lipid-lowering therapy should use an alternative statin with a well-characterized hepatic-impairment dose adjustment, and flibanserin is contraindicated regardless.

Women of Asian Ancestry

As noted above, rosuvastatin plasma levels run roughly 2-fold higher in Asian patients due to OATP1B1 and BCRP pharmacogenomics. Starting rosuvastatin at 5 mg daily is the FDA recommendation for this population. Flibanserin pharmacokinetics do not differ significantly by race in available data, and the flibanserin label does not specify race-based dose adjustments.

Postmenopausal Women

Flibanserin is FDA-approved only for premenopausal women with HSDD. It has no approved indication in postmenopausal women, and the benefit-risk calculation that drove FDA approval does not extend to that population. Rosuvastatin is used across the full adult spectrum for dyslipidemia and cardiovascular risk reduction.

What the Literature Does Not Yet Tell Us

No published, randomized pharmacokinetic crossover trial has enrolled healthy volunteers or HSDD patients to directly measure flibanserin-rosuvastatin AUC ratios, Cmax changes, or time-to-Cmax shifts. The current interaction classification relies on mechanistic reasoning from each drug's individual pharmacokinetic characterization, not from direct co-administration data.

A 2016 review of flibanserin's clinical pharmacology by Katz and colleagues confirmed that in vitro transporter inhibition studies showed no clinically relevant inhibition of OATP1B1 at therapeutic flibanserin concentrations. [2] That same review noted that formal DDI studies with OATP-substrate drugs were not conducted because in vitro signals did not meet the threshold for mandatory clinical follow-up under FDA guidance. The absence of a clinical study is not evidence of harm, but it is a data gap that physicians and patients deserve to know about.

The FDA Drug Interaction Guidance for Industry (2020) sets thresholds for when in vitro findings must be followed by in vivo studies. [6] Flibanserin's in vitro inhibition constant (Ki) for OATP1B1 did not meet the [I1]/IC50 threshold that would trigger a mandatory clinical OATP interaction study. That regulatory decision was made before rosuvastatin's transporter dependence was as thoroughly characterized as it is today, so re-evaluation with updated methodology would not be unreasonable in a research setting.