This page is sourced from MHRA-approved Summaries of Product Characteristics for licensed cannabinoid products, peer-reviewed RCT exclusion criteria, and UK regulatory standards.
Contraindications are graded absolute (prescribing is not appropriate under any circumstance) vs relative caution (prescribing may proceed with additional safeguards, MDT review, or enhanced monitoring). For MDT-trigger thresholds relating to relative cautions, see the Governance page.
| Domain | Contraindication | Source — Primary Citation |
|---|---|---|
| Hypersensitivity | Known hypersensitivity to CBD, THC, sesame oil (Epidyolex carrier), or excipients | Epidyolex SmPC [28], Sativex SmPC [67] |
| Pregnancy | Pregnancy or planning pregnancy | Epidyolex SmPC [28] (animal reproductive toxicity), Sativex SmPC [67] |
| Breastfeeding | Breastfeeding | Epidyolex SmPC [28], Sativex SmPC [67] (cannabinoids detected in breast milk) |
| Active psychosis | Current psychotic episode (THC-containing products) | Whiting JAMA 2015 [18]; Volkow NEJM 2014 [128]; Sativex SmPC [67] exclusion |
| Severe hepatic impairment | Child–Pugh C | Epidyolex SmPC [28]; Millar PK review [56] |
| Active untreated substance dependence | Current cannabis use disorder, active drug-seeking | Trial exclusion criteria from Hurd 2019 [13], Freeman 2020 [14] |
| Domain | Caution | Source — Primary Citation |
|---|---|---|
| Cardiovascular | Recent MI, stroke, dysrhythmia, uncontrolled HTN — especially THC-containing products | Whiting [18]; Sativex SmPC [67] |
| Moderate hepatic impairment | Child–Pugh A/B — dose adjustment may be required | Epidyolex SmPC [28] |
| Renal impairment | No dose adjustment data available | Epidyolex SmPC [28] |
| Psychosis / bipolar history | Personal or first-degree family history of psychosis or bipolar disorder (THC products) | Volkow [128]; Di Forti [129] |
| Active suicidal ideation | Current active suicidal ideation | McGuire 2018 [6] exclusion criteria |
| CYP inhibitors / inducers | Concomitant CYP3A4 / CYP2C19 inhibitors or inducers | Gaston 2017 [58]; Epidyolex SmPC [28]; see Interactions |
| Concomitant valproate | Hepatic risk amplified with CBD + valproate | Gaston [58]; Epidyolex SmPC [28] |
| Concomitant clobazam | Somnolence risk amplified | Gaston [58]; Epidyolex SmPC [28] |
| Driving / safety-critical occupation | Patients must be advised of impairment risk, especially THC | Sativex SmPC [67] driving warning |
| Polypharmacy | >5 chronic medications — increased DDI risk | Best practice under GMC [61] |
For each major indication, the following cautions are derived from the corresponding RCT exclusion criteria. Cross-link to the corresponding Evidence Matrix row.
Trial exclusion criteria from McGuire 2018 [6]: comorbid substance dependence; prior cannabis-induced psychosis; active suicidal ideation; significant hepatic impairment. Trial dose was 1000 mg/day on top of stable antipsychotic. Specials prescribing should follow the same exclusion logic.
Trial exclusion criteria from Bhattacharyya 2018/2024 [8], [59]: current substance dependence; active psychotic episode; significant medical comorbidity; pregnancy/breastfeeding. Trial dose was 600 mg/day for 21 continuous days.
Trial exclusion criteria from Masataka 2019 [47], de Faria 2020 [49], Berger 2022 [50]: active psychosis; current substance dependence; unstable medical condition; pregnancy. Doses ranged 300–600 mg/day.
Trial exclusion criteria from Bolsoni-Silva 2022 [12], Elms 2019 [25], Shannon 2019 [48]: active psychosis; current substance dependence; unstable cardiovascular disease. Dose not established.
Trial exclusion criteria from Kesner 2022 [26]: untreated sleep apnoea; current substance dependence; shift-work sleep disorder; pregnancy. Doses 75–300 mg/day.
Trial exclusion criteria from Müller-Vahl 2002 [19]: psychotic disorder; substance dependence; pregnancy. THC 2.5–10 mg/day — additional psychosis-risk caution applies.
Trial exclusion criteria from Hurd 2019 [13], Freeman 2020 [14]: active psychosis; unstable medical condition; pregnancy; concomitant opioid agonist therapy (for opioid-use trials). Doses 400–800 mg/day.
Per Sativex SmPC [67] and Novotna 2011 [20], Wade 2004 [21]: history of psychosis; significant cardiovascular disease; pregnancy/breastfeeding. Nabiximols titrated per SmPC.
Trial exclusion criteria from Chagas 2014 [52], de Faria 2020 [53], Leehey 2020 [54], Zuardi 2009 [55]: dementia (MMSE <24); active psychosis requiring antipsychotic escalation; significant hepatic impairment. Doses 75–300 mg/day.
Per Sativex SmPC [67] and Portenoy 2012 [22], Johnson 2010 [23], Lichtman 2018 [24]: history of psychosis; significant cardiovascular disease; active substance dependence. Nabiximols titrated per SmPC.
Trial exclusion criteria from NCT04527003 [43], [44], [45], [106]: pregnancy/planning pregnancy; significant hepatic impairment; concomitant hormonal therapy outside protocol. Up to 12.5 mg/kg/day (Phase 2).
Per Epidyolex SmPC [28] and Devinsky 2017 [1], Devinsky 2018 [2], Thiele 2018 [3], Thiele 2021 [4]: severe hepatic impairment (Child–Pugh C); concomitant valproate requires enhanced LFT monitoring; hypersensitivity to sesame oil carrier. Licensed doses 10–25 mg/kg/day.
Paediatric CBD prescribing is licensed for Dravet syndrome, Lennox-Gastaut syndrome, and tuberous sclerosis complex with Epidyolex per SmPC [28] and BPNA standards [64]. Paediatric prescribing requires CQC paediatric licence per [66]. Under-18 prescribing outside Epidyolex / Sativex licensed indications requires specialist MDT review (see Governance).
The following four highest-risk drug–cannabinoid pairs require mandatory enhanced monitoring or dose adjustment. See the full CBD Drug Interactions and THC Drug Interactions pages for complete tables.
Last reviewed: 2026-04-30 · Reviewer: Grace Blest-Hopley PhD · Next review: 2026-10-30