Synthetic progestin (emergency contraception)
Levonorgestrel and cannabis (marijuana, THC)
As cannabis becomes legal or decriminalised in more jurisdictions, the practical question of combining it with prescription medication comes up regularly. Levonorgestrel (Levonorgestrel) and cannabis share several pharmacological pathways, and the combination at 1.5mg is not automatically benign even where both are legal.
How cannabis affects Levonorgestrel
THC and other cannabinoids are metabolised partly by hepatic CYP enzymes, including CYP3A4 — the same pathway used by many Synthetic progestin (emergency contraception) medications. Frequent cannabis use can shift the metabolism of Levonorgestrel mildly. THC also has cardiovascular effects (increased heart rate, blood pressure changes) and central nervous system effects that can stack with Levonorgestrel's side-effect profile.
Practical guidance
Occasional moderate cannabis use is unlikely to cause clinically meaningful problems for most adults on Levonorgestrel at 1.5mg. Heavy daily use, edibles with high THC content, or cannabis combined with alcohol substantially raise the risk of dizziness, hypotension, impaired judgement and amplified side effects from Levonorgestrel. According to the prescribing information, the full list of recreational substances should be disclosed to the prescriber.
Frequently asked questions
Can I use cannabis while taking Levonorgestrel? ▾
For most adults at 1.5mg, occasional moderate cannabis is tolerated, but heavy daily use is not advised because of metabolic and additive cardiovascular effects with Levonorgestrel. The safe practice is to mention it to the prescriber.
Does CBD interact with Levonorgestrel? ▾
CBD inhibits several CYP enzymes including CYP3A4, which can raise plasma levels of medications that go through that pathway. For Levonorgestrel specifically, this depends on whether Levonorgestrel uses CYP3A4. Daily high-dose CBD products warrant a pharmacist check.
Products containing Levonorgestrel
More on Levonorgestrel
- With alcoholLevonorgestrel and alcohol — is it safe to drink?
- With foodShould Levonorgestrel be taken with food?
- Side effectsLevonorgestrel side effects: common, rare and warning signs
- Dosage guideLevonorgestrel dosage guide: how much to take and when
- OnsetHow fast does Levonorgestrel start working?
- DurationHow long does Levonorgestrel last?
The information on this website is provided for reference and educational purposes only. It does not replace consultation with a qualified healthcare professional.