Levonorgestrel

證據等級: L5

預測適應症: 6 個

Levonorgestrel: From Contraception to Acne

One-Sentence Summary

Levonorgestrel (LNG) is a synthetic progestogen widely used in hormonal contraception — including oral contraceptive pills, intrauterine systems (IUS), and implants. The TxGNN model predicts it may be effective for Acne (disease), with 5 clinical trials and 20 publications retrieved in this direction. However, mechanistic analysis reveals a fundamental paradox: LNG’s high intrinsic androgenic activity is more likely to worsen acne than improve it, and the clinical evidence to date derives entirely from LNG-containing combination oral contraceptives where the co-administered ethinylestradiol (EE) drives the anti-acne effect — not LNG itself.

Quick Overview

Item	Content
Original Indication	Hormonal contraception (oral, intrauterine, implant) — not registered in the Philippines per this evidence pack
Predicted New Indication	Acne (disease)
TxGNN Prediction Score	99.88%
Evidence Level	L3
Philippines Market Status	✗ Not Marketed
Number of Registrations	0
Recommended Decision	Hold

Why is This Prediction Reasonable?

Currently, detailed mechanism of action data is not available in this evidence pack (flagged as Data Gap DG002). Based on established pharmacological knowledge, Levonorgestrel is a 19-nortestosterone-derived synthetic progestogen with high androgenic potency — it binds androgen receptors with meaningful affinity, stimulates sebaceous gland secretion, and upregulates 5α-reductase activity. These are precisely the mechanisms that drive acne pathogenesis, not its resolution.

In combined oral contraceptives (COCs) containing both LNG and ethinylestradiol (EE), the EE component raises sex hormone-binding globulin (SHBG), which in turn lowers free circulating androgens. This anti-androgenic net effect is responsible for any observed acne improvement in LNG-containing COC users. The benefit is attributable to EE, not to LNG. Clinical comparative studies (e.g., EE/chlormadinone acetate vs EE/levonorgestrel) consistently show that switching from LNG-containing to anti-androgenic progestin-containing COCs improves acne outcomes — implying LNG is the less favourable progestin for acne-prone women.

The TxGNN graph model likely identified LNG’s association with acne through its knowledge graph proximity to female hormonal pathways and dermatological outcomes. This is a plausible graph-traversal artefact rather than a direct biological signal. As a standalone treatment for acne — without co-administered EE — LNG presents a mechanistic contradiction. Any further development in this indication would require robust evidence that LNG alone, at therapeutically relevant doses, reduces acne lesion counts without the confounding effect of estrogen.

Clinical Trial Evidence

Trial Number	Phase	Status	Enrollment	Key Findings
NCT01650168	N/A	Completed	101,498	Large prospective cohort comparing NOMAC-E2 COC vs LNG-containing COC for safety; provides comparative dermatological side-effect profiles including skin-related outcomes for LNG-OC users
NCT00480532	N/A	Completed	131	Doxycycline adjunct to continuous COC to reduce unscheduled bleeding; acne mentioned only as a known doxycycline indication — LNG’s independent effect on acne not assessable
NCT05570786	Phase 2	Completed	100	RCT of subdermal gestrinone pellet for endometriosis-associated pelvic pain; androgenic progestin context is informative for mechanism but primary endpoint is not acne
NCT00161226	N/A	Terminated	44	LNG-IUS for endometrial cancer prevention in obese women aged 40–50; trial terminated early; acne noted as a systemic side effect of oral progestins in background — not a therapeutic target
NCT05492487	Phase 2	Unknown	60	Mirena (LNG-IUS) vs megestrol for atypical endometrial hyperplasia in fertility-preserving setting; acne data, if any, would only appear in secondary safety endpoints

Note: None of the identified trials prospectively evaluated LNG as a primary treatment for acne. The closest evidence (NCT01650168) is a comparative safety cohort, not an efficacy trial for acne.

Literature Evidence

PMID	Year	Type	Journal	Key Findings
12196750	2002	RCT	J Am Acad Dermatol	Randomized placebo-controlled trial of EE 20 µg + LNG 100 µg OC for moderate acne; EE/LNG improved biochemical markers of androgenicity, suggesting net anti-androgenic effect of the combination — driven by EE-mediated SHBG elevation
6084924	1984	Clinical Study	Acta Derm Venereol	Serum testosterone and SHBG in 54 female acne patients treated with desogestrel/EE or LNG/EE OCs; pretreatment androgen abnormality in 57% of patients; both combinations reduced free testosterone, but the estrogen component is the common driver
15025547	2004	Review	Drugs	EE/chlormadinone acetate was significantly more effective than EE/LNG 0.03/0.15 mg for treating mild-to-moderate papulopustular acne — directly implying LNG is the less favourable progestin for acne management
21895044	2011	Review	Am J Clin Dermatol	EE/chlormadinone acetate for dermatological benefits including acne, hirsutism, and seborrhea; positions anti-androgenic progestins as superior to androgenic progestins like LNG for pilosebaceous disorders
16796485	2006	Review	J Womens Health	Drospirenone (anti-androgenic, antimineralocorticoid) vs LNG and MPA; drospirenone reduces acne and hirsutism while LNG does not — LNG used as the less favourable reference progestin
7825629	1995	Review/Mechanistic	Am J Med	Androgenicity of progestins: 19-nortestosterone-derived progestins (including LNG) retain androgenic receptor binding activity; explains why LNG-containing preparations may worsen androgen-sensitive conditions
14688179	2004	Clinical Study	Hum Reprod	LNG-IUS for endometriosis symptom management; supports LNG’s progestogenic efficacy via intrauterine route but is unrelated to acne
32909630	2020	Cochrane Review	Cochrane Database Syst Rev	LNG-IUS for endometrial hyperplasia; comprehensive systematic review confirming LNG’s endometrial antiproliferative properties — does not address acne
11727177	2001	Review	Semin Reprod Med	LNG-releasing IUS: mechanisms and clinical outcomes; background reading on LNG pharmacology
10652979	1999	Cohort Study	Hum Reprod Update	VTE risk with LNG-containing COCs vs third-generation progestins; LNG COCs show lower VTE risk — safety context, not acne-specific

Philippines Market Information

Levonorgestrel is not registered in the Philippines according to this evidence pack (0 active licenses, market status: Not Marketed). No product authorization data is available for tabulation.

Globally, LNG-containing products include emergency contraception (Plan B, Postinor), levonorgestrel-releasing IUS (Mirena, Liletta), and combination oral contraceptives. If Philippine registration status requires verification, a direct query to the Food and Drug Administration Philippines (FDA-PH) online drug database is recommended.

Safety Considerations

Please refer to the package insert for safety information. All safety fields in this evidence pack are flagged as Data Gap (DG001: TFDA package insert warnings/contraindications unavailable; DDI data: not found in query). The following general considerations are relevant based on LNG’s pharmacology:

Androgenic effects: Acne, hirsutism, and seborrhea may occur or worsen, particularly with high-dose or progestin-only preparations — this is mechanistically counterproductive to the predicted indication
Thromboembolic risk: LNG-containing COCs are associated with venous thromboembolism, though LNG-containing formulations carry lower VTE risk than some third-generation progestins
Hormonal effects: Irregular bleeding, mood changes, weight changes; breast tenderness

Conclusion and Next Steps

Decision: Hold

Rationale: The TxGNN model’s prediction of Levonorgestrel for acne treatment is mechanistically contradicted by LNG’s well-established androgenic activity — a property that promotes, rather than suppresses, androgen-driven skin pathology. All clinical evidence showing acne improvement derives from LNG combined with ethinylestradiol (EE), where EE’s SHBG-elevating effect drives the benefit. Comparative studies consistently rank LNG as an inferior progestin for acne-prone women relative to anti-androgenic progestins (drospirenone, chlormadinone, cyproterone). The Philippines regulatory pathway is also blocked by zero current registrations.

To proceed, the following is needed:

A clinical study isolating the effect of LNG alone (without EE) on acne lesion counts — no such study currently exists
Mechanistic studies clarifying whether any specific LNG dose or route (e.g., intrauterine, with minimal systemic exposure) could achieve a net anti-androgenic or sebosuppressive effect
Resolution of Data Gaps DG001 (package insert safety data) and DG002 (complete MOA characterization) before any safety assessment can be completed
Philippines FDA registration review and local regulatory pathway assessment before any market entry planning
Disclaimer

This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.