Levonorgestrel

證據等級: L5

預測適應症: 6 個

Levonorgestrel: From Contraception to Acne

One-Sentence Summary

Levonorgestrel is a synthetic progestin best known as a contraceptive agent (oral, emergency, and intrauterine formulations). The TxGNN model predicts it may be effective for Acne (disease), but the supporting evidence is mechanistically mixed: 5 clinical trials and 20 publications were retrieved, and the strongest literature signal points to the combined oral contraceptive’s estrogen component — not levonorgestrel itself — as the likely driver of any anti-acne effect.

Quick Overview

Item	Content
Original Indication	Contraception (based on known pharmacology; no SAHPRA-approved indication text is available — this evidence pack contains no South African licence records for levonorgestrel)
Predicted New Indication	Acne (disease)
TxGNN Prediction Score	99.88%
Evidence Level	L2
South Africa Market Status	Not Marketed
Number of SAHPRA Registrations	0
Recommended Decision	Hold

Why is This Prediction Reasonable?

Currently, detailed mechanism of action data for levonorgestrel is not available in this evidence pack. Based on known pharmacology, levonorgestrel is a 19-nortestosterone-derived synthetic progestin used primarily for contraception (oral combined pills, emergency contraception, and intrauterine systems); its contraceptive efficacy is well established, and progestins as a class are known to modulate the hypothalamic-pituitary-gonadal axis and androgen-related signalling — a pathway relevant to acne, which is an androgen-driven dermatological condition.

However, the evidence here contains an important mechanistic conflict. Levonorgestrel itself has comparatively high intrinsic androgenicity among progestins (PMID 7825629), which in theory could worsen rather than improve acne. The clinical benefit reported in the literature (e.g., PMID 12196750, PMID 6084924) is specifically for combined oral contraceptives containing ethinyl estradiol plus levonorgestrel, where the estrogen component lowers bioavailable androgens by raising sex hormone-binding globulin (SHBG) and suppressing ovarian androgen production. At least one comparative study (PMID 15025547) found that an alternative progestin (chlormadinone acetate) combined with estrogen was more effective against acne than the estrogen/levonorgestrel combination, suggesting levonorgestrel’s androgenicity may partially offset the estrogen-driven benefit.

In short, the TxGNN signal is plausible only in the context of levonorgestrel as part of a combined estrogen-progestin product, not as monotherapy or as the mechanistic driver of the effect. This distinction needs to be resolved before treating the prediction as a levonorgestrel-specific repurposing opportunity.

Clinical Trial Evidence

Trial Number	Phase	Status	Enrollment	Key Findings
NCT00480532	N/A	Completed	131	Continuous oral contraceptive + doxycycline study focused on bleeding patterns; doxycycline is a common acne adjunct, but the contraceptive’s progestin component and acne endpoint are not confirmed (Grade B relevance).
NCT01650168	N/A	Completed	101,498	Large safety cohort comparing nomegestrol acetate/estradiol vs. levonorgestrel-containing COCs; not acne-focused, low relevance (Grade C).
NCT00161226	N/A	Terminated	44	Levonorgestrel IUS trial for endometrial cancer prevention; terminated early, not an acne study (Grade C).
NCT05570786	Phase 2	Completed	100	Gestrinone implant for endometriosis-related pelvic pain; no confirmed levonorgestrel or acne link (Grade C).
NCT05492487	Phase 2	Unknown	60	Mirena (LNG-IUS) vs. megestrol for atypical endometrial hyperplasia; unrelated to acne (Grade C).

None of the retrieved trials directly and confirmedly test levonorgestrel for acne; relevance is indirect (Grade B/C only).

Literature Evidence

PMID	Year	Type	Journal	Key Findings
12196750	2002	RCT	J Am Acad Dermatol	Randomized, placebo-controlled trial: low-dose ethinyl estradiol 20mcg/levonorgestrel 100mcg improved moderate acne, attributed to reduced bioavailable androgens.
15025547	2004	Comparative trial/Review	Drugs	Ethinylestradiol/chlormadinone acetate was significantly more effective than ethinylestradiol/levonorgestrel for mild-to-moderate papulopustular acne.
6084924	1984	Comparative study	Acta Derm Venereol	Compared testosterone/SHBG changes and acne severity in patients on desogestrel- vs. levonorgestrel-containing OCs.
16796485	2006	Review	J Womens Health	Reviews drospirenone vs. medroxyprogesterone acetate/levonorgestrel/progesterone; notes drospirenone’s antiandrogenic profile reduces acne vulgaris occurrence relative to levonorgestrel.
21895044	2011	Review	Am J Clin Dermatol	Reviews androgen-driven dermatologic conditions (acne, hirsutism, FPHL) and hormonal treatment rationale.
7825629	1995	Review	Am J Med	Foundational review establishing that levonorgestrel, as a 19-carbon progestin, has relatively high intrinsic androgenicity compared with other progestins.

South Africa Market Information

No SAHPRA-registered products for levonorgestrel are recorded in this evidence pack. Market status is listed as Not Marketed, with 0 total licences. This means there is currently no local Professional Information (PI), no confirmed local formulation, and no basis to assess route-of-administration compatibility for this candidate within South Africa.

Safety Considerations

Please refer to the SAHPRA-approved Professional Information (PI) for safety information. Report adverse drug reactions to SAHPRA.

Note: This evidence pack flags a blocking data gap — TFDA label warnings/contraindications could not be retrieved — which by itself prevents a Stage 1 (S1) safety assessment.

Conclusion and Next Steps

Decision: Hold

Rationale: The evidence level (L2) rests on a single relevant RCT, and the mechanistic story is internally contradictory: levonorgestrel’s own androgenicity may work against, not for, an anti-acne effect, with benefit apparently driven by the estrogen component of combined products. Combined with a blocking safety data gap and zero SAHPRA registrations (drug not currently marketed in South Africa), there is insufficient basis to proceed.

To proceed, the following is needed:

TFDA/SAHPRA-equivalent Professional Information (warnings, contraindications) to clear the blocking data gap (DG001)
Confirmed mechanism of action data for levonorgestrel specifically (DG002)
Clarification of whether the acne benefit requires the estrogen component (i.e., is this a levonorgestrel effect or a combined-contraceptive-class effect)
Confirmation of any South African-registered levonorgestrel-containing product (combined OC or otherwise) as a route to clinical use
A dedicated trial or literature search isolating levonorgestrel-only formulations against acne outcomes
Disclaimer

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