Is oral Finasteride (Finasteride) contraindicated with anabolic steroids?

Finasteride and Anabolic Steroids: Contraindication Considerations

Finasteride should not be used concurrently with anabolic steroids due to potentially counterproductive effects and altered metabolism of both substances, which may impact their efficacy and safety profiles.

Mechanism of Action and Interactions

Finasteride is a 5α-reductase inhibitor that blocks the conversion of testosterone to dihydrotestosterone (DHT) 1. This mechanism directly conflicts with the intended effects of anabolic steroids, which are designed to enhance androgenic activity.

Pharmacological Considerations:

• Finasteride has a half-life of 6-8 hours and is approximately 90% plasma protein bound 1
• Anabolic steroids are metabolized through similar pathways as endogenous androgens
• When used together:
  • Finasteride may alter the metabolism of anabolic steroids
  • Anabolic steroids may overwhelm finasteride's inhibitory effects on 5α-reductase

Evidence from Guidelines

The North American Clinical Practice Guidelines for Hidradenitis Suppurativa (2025) mention finasteride as a potential anti-androgen therapy, but do not recommend combining it with anabolic agents 2. While not explicitly stating a contraindication, the therapeutic goals of these medications are fundamentally opposed.

The ESPEN guidelines on nutrition in cancer patients (2021) note that androgenic steroids have been investigated for their ability to increase protein synthesis and muscle mass, but do not recommend currently approved androgenic steroids for this purpose due to insufficient clinical data 2. This suggests caution when combining medications that affect androgenic pathways.

Clinical Implications

Potential Consequences of Concurrent Use:

1. Reduced Efficacy:

   • Anabolic steroids may override finasteride's DHT-blocking effects
   • Finasteride may diminish some of the desired effects of anabolic steroids

2. Altered Steroid Profiles:

   • Research shows that finasteride significantly affects steroid excretion profiles 3
   • Finasteride reduces production of 5α-steroids such as androsterone 3
   • This interaction could complicate monitoring and dosing of anabolic steroids

3. Metabolic Pathway Disruption:

   • Finasteride decreases multiple 5α-reduced steroids and some 5-ene steroids 4
   • These alterations could unpredictably affect the metabolism of exogenous anabolic steroids

4. Potential for Increased Side Effects:

   • Both medications can cause sexual dysfunction independently
   • Combined use may increase risk of adverse effects

Practical Recommendations

For patients requiring treatment for conditions where finasteride is indicated (such as androgenetic alopecia or benign prostatic hyperplasia):

1. Avoid concurrent use with anabolic steroids

2. Consider alternatives:

   • For hair loss: Topical minoxidil may be a better option for those using anabolic steroids 5
   • For BPH: Alpha-blockers may be preferable if anabolic steroid use cannot be discontinued

3. If treatment with finasteride is essential:

   • Discontinue anabolic steroids
   • Allow sufficient washout period before initiating finasteride
   • Monitor for efficacy and side effects closely

Conclusion

While there is no absolute contraindication listed in drug labeling, the concurrent use of finasteride and anabolic steroids represents a pharmacologically contradictory approach that may reduce the efficacy of both agents and potentially increase side effects. The opposing mechanisms of action make this combination illogical from a therapeutic standpoint.