Singulair and CBD — interaction profile and FAQ
Cannabidiol (CBD) is widely used as an over-the-counter wellness product, and many people taking Singulair (Montelukast) — used for Singulair is approved in adults and children for the maintenance treatment of asthma, including exercise-induced bronchospasm, and for the treatment of seasonal and perennial allergic rhinitis when co… — wonder whether the two are safe to combine. Unlike most herbal products, CBD has documented interactions with several drug-metabolising enzymes, which means it can change blood levels of co-administered medications. Below is a focused look at the Singulair-and-CBD question at the 4mg, 5mg, 10mg dosing strengths.
How CBD can affect Singulair blood levels
CBD inhibits several cytochrome P450 enzymes — most notably CYP3A4, CYP2C19 and CYP2D6 — which together metabolise a large fraction of prescription medications. Singulair, with active ingredient Montelukast, may or may not be metabolised by these enzymes; if it is, concomitant CBD can raise Singulair blood levels and increase the risk of dose-related side effects. Conversely, in some pathways, induction or competition for transporters can lower exposure. The clinically relevant size of this effect depends on the CBD dose, formulation and individual hepatic metabolism.
Practical guidance for combined use
According to general clinical guidance, anyone planning to combine Singulair at the 4mg, 5mg, 10mg doses with regular CBD use should discuss this with the prescriber and ideally check the Singulair prescribing information and an interaction database (e.g. Lexicomp, the FDA Drug Interactions guidance) for the Montelukast entry. Practical steps include starting at low CBD doses, separating CBD and Singulair doses by several hours where feasible and monitoring for side effects (sedation, dizziness, gastrointestinal symptoms or laboratory changes) during the first weeks. Pure isolate CBD has fewer co-formulants but the CYP-inhibition signal is similar.
Frequently asked questions
Is it safe to use CBD with Singulair? ▾
Whether CBD is safe to combine with Singulair depends on the metabolic pathway of Montelukast, the CBD dose and the indication for which Singulair is taken at the 4mg, 5mg, 10mg dose. For many medications the interaction is mild and manageable; for narrow-therapeutic-index drugs (anticoagulants, anti-epileptics, immunosuppressants and some psychiatric medications) the combination warrants closer follow-up. Discuss with the prescriber and check an interaction database before starting CBD.
How much time should I leave between CBD and Singulair? ▾
For most medications, separating CBD and Singulair by several hours reduces, though does not eliminate, the metabolic interaction; for steady-state regimens with cumulative drug levels, simple time separation has limited effect. According to general pharmacological principles, the more meaningful step is establishing a stable CBD dose, monitoring symptoms and laboratory values, and adjusting Singulair dosing under the prescriber's guidance rather than relying on timing alone.
More on Singulair
- With alcoholSingulair and alcohol — is it safe to drink?
- With foodShould Singulair be taken with food?
- Side effectsSingulair side effects: common, rare and warning signs
- Dosage guideSingulair dosage guide: how much to take and when
- OnsetHow fast does Singulair start working?
- DurationHow long does Singulair last?
The information on this website is provided for reference and educational purposes only. It does not replace consultation with a qualified healthcare professional.