Addyi Pre-Surgery Hold Window: What Patients and Clinicians Need to Know

What Is Flibanserin and Why Does Surgery Create Risk

Flibanserin is the only FDA-approved non-hormonal treatment for acquired, generalized HSDD in premenopausal women. The FDA granted approval in August 2015, and the drug carries a Risk Evaluation and Mitigation Strategy (REMS) because of documented hypotension and syncope risks. Surgery amplifies every one of those risks.

How Flibanserin Works

Flibanserin acts as a serotonin 1A receptor agonist and serotonin 2A receptor antagonist. It also has moderate antagonist activity at dopamine D4 receptors. This mixed neurochemical profile is what improves desire in some premenopausal women, but it also sets the stage for significant pharmacodynamic collisions with perioperative agents.

Why the Surgical Setting Is Especially Dangerous

Operating rooms use agents that independently lower blood pressure and depress the CNS: volatile anesthetics such as sevoflurane and desflurane, propofol, opioids, and benzodiazepines. When any of these combine with residual flibanserin, the patient faces:

• Additive or synergistic CNS depression
• Pronounced hypotension from dual vasodilatory pathways
• Increased sedation duration in post-anesthesia care

The FDA prescribing information for flibanserin explicitly categorizes CNS depressants as contraindicated or requiring strong caution, which makes any planned surgery a mandatory medication review event.

The 7-Day Hold: Where the Number Comes From

Seven days is not arbitrary. Three separate pharmacokinetic and pharmacodynamic rationales support this figure.

Half-Life and Washout Arithmetic

Flibanserin's terminal half-life averages approximately 11 hours in healthy volunteers, as reported in the FDA clinical pharmacology review. Five half-lives equal roughly 55 hours, meaning plasma concentrations fall to <3% of steady-state within about 2.3 days. The 7-day hold accounts for:

1. Active metabolites with longer effective half-lives
2. Inter-patient CYP2C19 variability (poor metabolizers clear the drug more slowly)
3. Residual CYP3A4 enzyme induction/inhibition normalization

Because flibanserin is primarily metabolized by CYP3A4 and to a lesser extent CYP2C19, as detailed in FDA pharmacokinetic data, patients on CYP3A4 inhibitors (many of which appear in perioperative regimens) accumulate higher flibanserin levels.

CYP3A4 Inhibitors in the Perioperative Period

Several drugs common in perioperative care inhibit CYP3A4 meaningfully:

• Diltiazem: frequently used for rate control; raises flibanserin AUC approximately 4-fold per FDA labeling
• Fluconazole: antifungal prophylaxis used in some surgical centers; raises flibanserin AUC approximately 7-fold
• Erythromycin and clarithromycin: sometimes given perioperatively; each substantially increases flibanserin exposure

Any of these agents on top of residual flibanserin can push plasma concentrations into a range where syncope probability increases sharply. The FDA's drug interaction table in the Addyi label lists moderate CYP3A4 inhibitors as requiring a 2-week offset before starting flibanserin, which gives a sense of how seriously this interaction class is treated.

Pharmacodynamic Overlap With Anesthetic Agents

Independent of plasma-level arithmetic, volatile anesthetics and propofol depress the CNS through GABA-A potentiation and other mechanisms. Flibanserin's serotonergic and dopaminergic activity adds to this depression unpredictably. A 2014 systematic review in the British Journal of Anaesthesia on serotonergic drugs in anesthesia confirmed that serotonin-active compounds can alter anesthetic requirements and cardiovascular stability during induction, even at subtherapeutic plasma concentrations.

Clinical Evidence: What the BEGONIA Trial Tells Us About the Drug's Profile

Understanding why the pre-surgery hold matters requires understanding what flibanserin actually does at therapeutic doses.

BEGONIA Trial Design and Results

The BEGONIA trial (published in the Journal of Sexual Medicine, 2014) enrolled premenopausal women with generalized, acquired HSDD in a 24-week randomized controlled trial. BEGONIA (N<1,000, exact N per the published paper at PMID 24628797) found that flibanserin 100 mg taken at bedtime produced a statistically significant increase in satisfying sexual events compared to placebo (P<0.05). Female Sexual Function Index desire domain scores also improved significantly.

Adverse events in BEGONIA included dizziness (11.4% flibanserin vs. 2.2% placebo), somnolence (10.0% vs. 2.8%), and nausea (9.2% vs. 4.4%). These numbers matter for surgical planning because dizziness and somnolence reflect CNS activity that anesthesiologists must factor into their protocols.

What BEGONIA Does Not Tell Us

BEGONIA excluded women on CYP3A4 inhibitors and those with planned surgeries, so the trial provides no direct data on perioperative risk. The FDA medical review of the Addyi NDA addresses this gap by drawing on dedicated drug-interaction pharmacokinetic studies rather than trial outcomes data.

The ADDYI REMS Program and Its Surgical Implications

The FDA requires flibanserin to be distributed under a REMS because of the drug's hypotension/syncope risk in the presence of alcohol and CNS depressants. The current REMS program documentation mandates:

• Prescribers must counsel patients about all CNS depressants, not just alcohol
• Pharmacies must verify patients received counseling before each new fill
• Patients must sign a Patient-Prescriber Agreement acknowledging the alcohol and CNS-depressant risks

Surgery involving anesthesia is the most concentrated source of CNS-depressant exposure any patient will encounter. The REMS therefore makes pre-surgical counseling a logical extension of the existing safety framework, even though the label does not specify an exact surgical hold duration in the REMS documents themselves.

Practical REMS Compliance Steps Before Surgery

1. Confirm flibanserin on the patient's medication reconciliation list at the pre-anesthesia visit
2. Document the date of the last dose
3. Verify 7 or more days have elapsed before any induction agent is given
4. Flag the case for the anesthesiologist if the hold was <7 days for any reason (emergency surgery)

Emergency Surgery: When the 7-Day Hold Is Impossible

Trauma and urgent procedures cannot always wait. If a patient on flibanserin requires surgery within 7 days of her last dose, the anesthesia team should:

Dose-Time Risk Stratification

• <24 hours since last dose: plasma concentrations likely near peak or early decline; highest risk window; use minimum effective doses of CNS depressants, have vasopressors immediately available
• 24 to 72 hours: approximately 3 to 6 half-lives elapsed; risk substantially reduced but not eliminated in CYP2C19 poor metabolizers
• 72 hours to 7 days: >99% drug cleared in most patients; residual risk is pharmacodynamic rather than pharmacokinetic

The American Society of Anesthesiologists' general principles on preoperative medication management do not address flibanserin specifically, but their framework for serotonergic and CNS-active drugs applies directly. Anesthesiologists should anticipate lower vasopressor thresholds and document the flibanserin status in the pre-induction note.

Intraoperative Monitoring Adjustments

Patients with recent flibanserin exposure benefit from:

• Continuous arterial line placement if the procedure duration exceeds 60 minutes
• Reduced induction doses of propofol (20 to 30% reduction is a reasonable starting point)
• Phenylephrine or norepinephrine on the push rather than ephedrine, given serotonin-norepinephrine dynamics

These are institutional adaptations, not FDA-label requirements, and the prescribing anesthesiologist bears clinical judgment responsibility.

Drug Interactions Most Relevant to the Perioperative Window

Flibanserin carries a long interaction list. The ones most likely to appear in a perioperative context deserve individual attention.

Moderate and Strong CYP3A4 Inhibitors

Fluconazole raises flibanserin AUC approximately 7-fold and maximum concentration approximately 2-fold. The FDA interaction data classify this as contraindicated during flibanserin use. Surgical prophylaxis protocols that include fluconazole must therefore be reviewed if there is any chance flibanserin remains in the patient's system.

Diltiazem, grapefruit juice (commonly ignored but pharmacologically meaningful), and ciprofloxacin are moderate inhibitors. Even moderate inhibition at a time when flibanserin has only partially cleared can re-raise plasma concentrations into a symptomatic range. A PubMed review of CYP3A4-mediated drug interactions outlines the general mechanism by which inhibitors prolong psychoactive drug exposure and why extended washout periods are pharmacokinetically justified.

CNS Depressants

Opioids, benzodiazepines, and sleep aids all carry pharmacodynamic interaction risk with flibanserin. The FDA's 2015 approval documents note that in CNS-depressant interaction studies, subjects showed measurable blood pressure drops and increased sedation scores. Post-operative pain management protocols that include opioids therefore carry elevated risk if flibanserin has not been fully cleared.

Alcohol

Alcohol is the interaction the REMS focuses on most heavily, but it also appears in the surgical context: some post-operative patients resume drinking within days of discharge. Patients should be counseled that the 7-day post-surgical restart window for flibanserin does not mean they can drink while taking it. Each bedtime dose still requires the 2-hour pre-dose and overnight alcohol-free period. The REMS Patient-Prescriber Agreement makes this obligation explicit.

Safe Restart After Surgery

The question of when to restart flibanserin after surgery is as clinically meaningful as when to stop it.

The 24-Hour Restart Rule

The FDA label does not state a post-operative restart interval in explicit terms, but clinical pharmacokinetic logic supports waiting at least 24 hours after the last dose of any CNS depressant used intraoperatively or in the immediate recovery period. By 24 hours:

• Propofol is fully cleared (context-sensitive half-time for a 2-hour infusion is approximately 40 minutes; after 24 hours, plasma concentrations are negligible)
• Short-acting benzodiazepines (midazolam) are metabolized
• Residual volatile anesthetic is exhaled

Opioids present a longer consideration. If the patient is on a scheduled opioid regimen for post-operative pain, restarting flibanserin should wait until the opioid is either discontinued or transitioned to as-needed dosing at low frequency. A clinical pharmacology review published via NIH on combined serotonergic and opioid exposures supports conservative restart timing.

Reassessing HSDD After Surgery

Surgery and anesthesia temporarily alter neuroendocrine function. Cortisol spikes, sleep disruption, and post-operative pain can all suppress sexual desire independently of HSDD. Restarting flibanserin within the first week post-operatively may confound interpretation of any symptom changes. A 4-week post-operative clinical reassessment before restart is reasonable in patients who had major procedures, though this is a practical suggestion rather than a guideline-mandated interval.

Patient Counseling Checklist for the Pre-Surgery Hold

Prescribers and pharmacists should cover these points explicitly at the pre-surgical visit.

What to Tell the Patient

• Stop flibanserin exactly 7 days before the scheduled surgery date, not 7 days before admission
• Inform every member of the surgical team, including the nurse who completes pre-operative medication reconciliation, that flibanserin is (or was recently) in use
• Do not restart without a conversation with the prescribing clinician, even if the surgery went smoothly
• Understand that missing one or two doses of flibanserin before the hold has minimal impact on HSDD symptom control over a 1-to-2-week period; the drug has no withdrawal syndrome

Documenting the Hold

Document the planned last-dose date in the chart at the time the surgery is scheduled, not the day before. If the patient is seen in a telehealth setting, a secure message confirming the hold date and the restart plan creates a clear record for the surgical team to reference.

Flibanserin Efficacy Context: Is the Hold Worth It

Some patients resist stopping flibanserin because their HSDD symptoms are well-controlled and they fear losing that benefit. Setting expectations clearly prevents non-compliance.

Short-Term Symptom Impact of Stopping

Flibanserin does not produce dependence. Stopping for 7 to 10 days will not cause rebound worsening beyond the baseline HSDD state. The BEGONIA trial data show that treatment effect accumulates over weeks to months, so a 1-to-2-week interruption is unlikely to reverse the therapeutic response established over months of use.

Weighing the Risk

The risk calculus is straightforward. Hypotension under general anesthesia can result in myocardial ischemia, stroke, or cardiac arrest. The modest short-term loss of HSDD symptom benefit is not a reasonable trade-off against those outcomes. A 2019 analysis of perioperative hypotension published in Anesthesiology showed that even brief episodes of mean arterial pressure below 65 mmHg are independently associated with myocardial injury and acute kidney injury in surgical patients. Any drug that increases hypotension risk in that setting must be held.

A Note on Hormonal Interactions and Premenopausal Status

Flibanserin is approved specifically for premenopausal women. Hormonal fluctuations across the menstrual cycle can alter CYP enzyme activity and therefore flibanserin clearance. Research on sex-hormone effects on CYP3A4 activity confirms that estrogen and progesterone modulate hepatic enzyme expression. If a patient schedules surgery at a point in her cycle where progesterone is elevated (luteal phase), CYP3A4 activity may be slightly suppressed, theoretically slowing flibanserin clearance. This is an additional argument for erring toward the full 7-day hold rather than trying to time surgery for peak clearance days.

Addyi Clinical Update: Recent Regulatory and Label Changes

The REMS for Addyi was updated in 2019 to reduce some of the prescriber burden while maintaining the core safety requirements. The 2019 REMS revision removed the requirement for a certified healthcare provider to administer the drug (given it is oral and self-administered) but kept the prescriber-certification and patient-counseling requirements.

No changes to the perioperative guidance have been issued since initial approval. The 7-day hold recommendation in clinical practice derives from the label's pharmacokinetic data and the interaction profile rather than from a specific labeled perioperative statement.

The Endocrine Society's clinical practice guideline on female sexual dysfunction acknowledges flibanserin as a pharmacologic option for HSDD but does not provide surgical hold guidance, reinforcing that perioperative management remains in the hands of the anesthesiologist and prescribing clinician using first-principles pharmacokinetics.