Can dienogest (synthetic progestin) cause low libido?

Dienogest and Low Libido

Yes, dienogest can cause decreased libido as a documented side effect, with studies specifically identifying it as one of the major adverse effects of this synthetic progestin.1

Mechanism and Evidence

Dienogest is a synthetic progestin with unique pharmacological properties that is commonly used in the treatment of endometriosis at a dosage of 2 mg/day and as a component in some hormonal contraceptives. It has several key characteristics that may contribute to its effects on libido:

• Dienogest exhibits highly selective binding to progesterone receptors with strong progestational effects2
• It has significant antiandrogenic activity2, which may directly impact sexual desire
• It demonstrates moderate antigonadotropic effects3

In one of the earliest clinical studies of dienogest for endometriosis treatment, decreased libido was specifically identified as one of the major side effects reported by patients taking 2 mg daily1. This finding is particularly significant as it was highlighted alongside menstrual spotting as the primary adverse effects in this pioneering study.

Hormonal Contraceptives and Sexual Function

The impact of hormonal contraceptives on female sexual function is complex:

• Hormonal contraceptives in general can have mixed effects on libido, with some women experiencing decreases, some increases, and the majority being unaffected4
• Progestins with antiandrogenic properties (like dienogest) may be more likely to negatively affect libido due to their impact on androgen levels
• A 1997 study demonstrated that ethinylestradiol-dienogest combinations significantly decreased serum androgens, including:
  • Total testosterone (by 17-40%)
  • Free testosterone (by 48-54%)
  • Dehydroepiandrosterone sulfate (by 51%)5

Clinical Considerations

When evaluating sexual dysfunction in patients taking dienogest, consider:

1. Timing of symptoms: Decreased libido typically emerges after starting dienogest therapy
2. Differential diagnosis: Other causes of low libido should be considered, including:
   • Psychogenic causes
   • Other medication effects (e.g., spironolactone, beta-blockers)
   • Underlying hormonal abnormalities
   • Chronic illness effects6

Management Options

For patients experiencing decreased libido while on dienogest:

1. Benefit-risk assessment: Weigh the therapeutic benefits of dienogest (e.g., endometriosis symptom control) against the impact on quality of life from decreased libido
2. Alternative treatments: Consider alternative progestins or treatment approaches if appropriate
3. Dose adjustment: In some cases, a lower dose may maintain efficacy while reducing side effects
4. Referral: For persistent issues, referral to appropriate specialists for evaluation and management may be warranted6

Important Caveats

• Sexual side effects of hormonal contraceptives are generally understudied4
• Individual responses to progestins vary significantly
• The impact on libido may be more pronounced in certain patient populations
• Patients should be informed about this potential side effect before starting therapy

In conclusion, decreased libido is a recognized side effect of dienogest that should be discussed with patients prior to initiating therapy and monitored throughout treatment.