CBD Guide: Medical Uses, Doses, Drug Interactions and Safety

Q: What is CBD used for medically?

The only FDA-approved CBD drug is Epidiolex, prescribed for Dravet syndrome, Lennox-Gastaut syndrome, and tuberous sclerosis complex. Clinical evidence also supports CBD for anxiety at 300-600 mg doses, and there is moderate evidence for chronic pain and sleep disturbances secondary to pain or anxiety.

Q: What is the correct dose of CBD?

Clinical trial doses vary by condition: Epidiolex for epilepsy uses 5-20 mg/kg/day; anxiety studies used 300-600 mg single doses; pain studies ranged 50-600 mg. Most consumer products contain 10-50 mg per serving, far below clinical research doses.

Q: Does CBD interact with medications?

Yes. CBD inhibits CYP3A4 and CYP2C9 liver enzymes. This can raise blood levels of warfarin, SSRIs, benzodiazepines, antiepileptics, and immunosuppressants. Always consult your doctor before combining CBD with prescription medications.

Q: Is CBD safe for everyone?

No. CBD should be avoided during pregnancy and breastfeeding. Children should only use pharmaceutical Epidiolex under medical supervision. Elderly patients face higher drug interaction risk due to slower metabolism. High doses can elevate liver enzymes.

Key Findings

The only FDA-approved CBD drug is Epidiolex, prescribed at 5–20 mg/kg/day for Dravet syndrome, Lennox-Gastaut syndrome, and tuberous sclerosis complex.
Anxiety studies used single doses of 300–600 mg — far above the 10–50 mg found in most consumer products.
CBD inhibits liver enzymes CYP3A4 and CYP2C9, creating clinically significant interactions with warfarin, SSRIs, benzodiazepines, and antiepileptics.
Drug interactions between CBD and prescription medications are underreported and poorly understood by most consumers.
No safe dose of CBD has been established for pregnancy or breastfeeding — it should be avoided entirely.
At high doses CBD can elevate liver enzymes; regular monitoring is recommended when taking pharmaceutical CBD.
Third-party COA from an ISO-accredited lab is the minimum quality standard for any CBD product.

What CBD Is Approved For

Cannabidiol (CBD) is a phytocannabinoid found in cannabis and hemp. It does not produce intoxication. The U.S. Food and Drug Administration has approved exactly one CBD-based pharmaceutical: Epidiolex (GW Pharmaceuticals / Jazz Pharmaceuticals), an oral solution indicated for three conditions:

Dravet syndrome — a severe childhood-onset epilepsy resistant to standard antiepileptics
Lennox-Gastaut syndrome — a complex epilepsy with multiple seizure types
Tuberous sclerosis complex (TSC) — a genetic disorder causing benign tumours and seizures

Epidiolex approval does not validate broader CBD health claims. Over-the-counter CBD products are dietary supplements, not drugs, and cannot legally claim to treat any medical condition.

Evidence by Condition

Condition	Evidence Level	Clinical Dose Used	Notes
Epilepsy (Dravet / LGS)	FDA-approved	5–20 mg/kg/day	Pharmaceutical Epidiolex only
Anxiety	Clinical RCTs	300–600 mg single dose	Well above consumer product doses
Pain & Inflammation	Moderate	50–600 mg/day	Meta-analyses support modest benefit
Sleep	Mixed	25–175 mg/day	Often indirect via anxiety/pain relief
PTSD	Emerging	300–400 mg/day	Promising preliminary results
Addiction / Withdrawal	Early	400–800 mg/day	Opioid and cannabis use disorder studies
Cancer Nausea	Limited	Varies widely	THC usually more effective for nausea
Parkinson’s	Early	75–300 mg/day	Small trials; tremor and sleep benefit noted

How CBD Works: Mechanism of Action

CBD is pharmacologically promiscuous — it acts on multiple receptor systems simultaneously:

FAAH inhibition: CBD slows the breakdown of anandamide (the endogenous “bliss molecule”), producing indirect endocannabinoid system upregulation without binding CB1 receptors directly.
5-HT1A agonism: CBD acts as a partial agonist at serotonin 5-HT1A receptors — the primary mechanism behind its anti-anxiety effects at high doses.
CB2 receptor modulation: Weak CB2 activity contributes to anti-inflammatory effects, particularly relevant in arthritis and neuroinflammation research.
TRPV1 activation: CBD activates transient receptor potential vanilloid 1 (TRPV1), a pain-sensing ion channel, contributing to analgesic effects.
GPR55 antagonism: Blocking this receptor may contribute to anticonvulsant and anti-proliferative effects.

Drug Interactions: The Critical Risk

CBD is metabolised by and inhibits cytochrome P450 liver enzymes, particularly CYP3A4 and CYP2C9. This creates the potential to raise blood levels of many prescription drugs to dangerous concentrations — a risk significantly underreported in consumer CBD marketing.

CYP3A4 Interactions

CYP3A4 metabolises approximately 50% of all medications. CBD inhibition of this enzyme can increase plasma levels of:

Benzodiazepines (clonazepam, diazepam, alprazolam) — increased sedation risk
Some SSRIs (sertraline, escitalopram) — serotonin syndrome risk at high CBD doses
Antiepileptics (carbamazepine, phenytoin) — toxicity or reduced efficacy
Immunosuppressants (tacrolimus, cyclosporine) — narrow therapeutic index, dangerous
Some statins (atorvastatin, lovastatin) — myopathy risk

CYP2C9 Interactions

Warfarin — CBD inhibits warfarin metabolism, increasing INR and bleeding risk. This interaction is clinically confirmed.
NSAIDs (ibuprofen, naproxen) — levels may increase modestly
Some antidiabetics (glipizide, tolbutamide) — hypoglycaemia risk

Drug Class	Interaction Type	Clinical Significance	What to Do
Warfarin	CYP2C9 inhibition	High	Monitor INR closely; avoid without physician oversight
Benzodiazepines	CYP3A4 inhibition	High	Increased sedation; consult prescriber
Antiepileptics	CYP3A4 inhibition	Moderate–High	Level monitoring required
SSRIs	CYP3A4 inhibition	Moderate	Watch for serotonin syndrome symptoms
Immunosuppressants	CYP3A4 inhibition	High	Do not combine without specialist guidance
Statins (some)	CYP3A4 inhibition	Moderate	Myopathy risk; pravastatin is safer (not CYP3A4-dependent)

CBD Dosing by Condition

Condition	Study Dose	Consumer Product Typical	The Gap
Epilepsy	5–20 mg/kg/day	10–50 mg/day	10x–100x below study doses
Anxiety	300–600 mg	10–50 mg/day	6x–60x below study doses
Chronic Pain	50–600 mg/day	10–50 mg/day	Overlap only at lower end of study range
Sleep	25–175 mg/day	10–50 mg/day	Overlap possible at high end
PTSD	300–400 mg/day	10–50 mg/day	6x–40x below study doses

Safety Profile

CBD is generally well tolerated but not risk-free. Side effects documented in clinical trials include:

Drowsiness and sedation — especially at doses above 150 mg; additive with alcohol and sedating medications
Diarrhoea and GI upset — dose-dependent; most common adverse effect in Epidiolex trials
Appetite changes — both increased and decreased appetite reported across studies
Elevated liver enzymes (ALT/AST) — seen at high doses (>20 mg/kg/day); requires monitoring in long-term pharmaceutical CBD use
Drug interactions — the most clinically significant safety concern (see drug interaction section above)

Special Populations

Population	Recommendation	Reason
Pregnant	Avoid entirely	No safe dose established; developmental risk
Breastfeeding	Avoid entirely	CBD passes into breast milk; infant exposure risk unknown
Children	Medical supervision only	Epidiolex only; OTC products not validated for paediatric use
Elderly	Increased caution	Slower metabolism → higher drug interaction risk; start low

Choosing a Quality CBD Product

The CBD supplement market is largely unregulated. Key quality indicators:

Certificate of Analysis (COA) — a lab report showing cannabinoid content, potency, and contaminant testing. Must be current (within 12 months) and batch-specific.
ISO-accredited laboratory — ISO 17025 accreditation means standardised testing protocols. Avoid products with in-house lab testing only.
Third-party tested — the testing lab must be independent from the manufacturer.
THC content verified — hemp-derived CBD must contain <0.3% THC by dry weight. COA should confirm this. Higher THC may cause positive drug tests.
Accurate labelling — studies have found 25–50% of CBD products are mislabelled for potency. COA verification is essential.
Extraction method — CO² extraction is the cleanest standard. Avoid solvent-extracted products without residual solvent testing on the COA.

Frequently Asked Questions

What is CBD used for medically?

The only FDA-approved indication for CBD is severe epilepsy (Epidiolex for Dravet syndrome, Lennox-Gastaut syndrome, and TSC). Beyond that, clinical evidence supports CBD for anxiety at 300–600 mg doses, and there is moderate evidence for chronic pain and sleep disturbances. Claims about CBD treating cancer, diabetes, or Alzheimer’s disease are not supported by current clinical evidence.

What is the correct dose of CBD?

There is no universal correct dose — effective doses vary by condition, body weight, metabolism, and product quality. Clinical trials used 300–600 mg for anxiety and 5–20 mg/kg for epilepsy. Consumer products typically contain 10–50 mg per serving. For most medical applications, consumer product doses are insufficient. A physician familiar with cannabis medicine is the best guide for therapeutic dosing.

Does CBD interact with medications?

Yes — this is one of the most important and underreported CBD safety issues. CBD inhibits CYP3A4 and CYP2C9 liver enzymes, which process roughly 50% of all pharmaceuticals. Confirmed interactions include warfarin (bleeding risk), benzodiazepines (excessive sedation), antiepileptics (toxicity or reduced efficacy), SSRIs, immunosuppressants, and some statins. Always consult your prescribing doctor before combining CBD with any prescription medication.

Is CBD safe for everyone?

No. CBD should be avoided during pregnancy and breastfeeding. Children should only use pharmaceutical Epidiolex under strict medical supervision. Elderly patients metabolise CBD more slowly and face higher drug interaction risk. People with liver conditions should use caution — CBD can elevate liver enzymes at high doses. For otherwise healthy adults taking no medications, CBD at low-to-moderate doses has a good short-term safety profile.