Plan B vs Clomiphene: side-by-side comparison
Plan B (Levonorgestrel) and Clomiphene (Clomiphene) both belong to the Hormones and Birth Control class. They share clinical context but use different active ingredients. The choice between them depends on mechanism nuances, side-effect profile and individual response.
| Property | Plan B | Clomiphene |
|---|---|---|
| Active ingredient | Levonorgestrel | Clomiphene |
| Manufacturer | Foundation Consumer Healthcare | Various generics |
| Class | Hormones and Birth Control | Hormones and Birth Control |
| Strengths | 1.5mg | 50mg |
| Forms | tablet | tablet |
What's the same
Plan B and Clomiphene both belong to the Hormones and Birth Control class and are used for partially overlapping indications. The active ingredients — Levonorgestrel vs Clomiphene — share the same therapeutic approach, so many safety and management points carry across both.
Key differences
Meaningful differences are in active ingredient (Levonorgestrel vs Clomiphene), strengths (1.5mg vs 50mg), forms (tablet vs tablet), and the mechanism, half-life and side-effect nuances that distinguish members of the class.
Mechanism and action
Plan B: Plan B's primary mechanism is delaying or preventing ovulation when taken before the LH surge. Clomiphene: Clomiphene blocks estrogen receptors at the hypothalamus, preventing the negative feedback that estrogen normally exerts on gonadotropin-releasing hormone production.
When Plan B is preferred
Plan B is indicated for emergency contraception after unprotected intercourse or known/suspected contraceptive failure, in women of reproductive age.
When Clomiphene is preferred
Clomiphene is indicated for ovulation induction in women with anovulatory infertility and intact pituitary-ovarian axis function, when other causes of infertility have been excluded or are being addressed.
Frequently asked questions
Is Plan B or Clomiphene better? ▾
There is no single answer. Plan B and Clomiphene both belong to the Hormones and Birth Control class but differ in mechanism nuances, half-life and side-effect profile. Preference depends on the patient, the prescriber and prior response to other therapies.
Can I switch from Plan B to Clomiphene? ▾
Switching within the Hormones and Birth Control class is done under supervision, typically using equivalent doses and a follow-up period to confirm response and tolerance. It is not a self-directed decision.
Do Plan B and Clomiphene have the same side effects? ▾
They share many of the Hormones and Birth Control class side effects, with differences from mechanism and dose. Each medication's prescribing information lists specifics.
More Plan B comparisons
The information on this website is provided for reference and educational purposes only. It does not replace consultation with a qualified healthcare professional.