Synthetic Cannabinoids (K2/Spice): Effects, Duration, and Dangers

"Herbal incense," "K2," or "Spice" are plant materials sprayed with synthetic cannabinoid receptor agonists (SCRAs). They are **not** cannabis; they are unpredictable, potent, and dangerous.

Pharmacology

• Full CB1 receptor agonists (THC is partial) → much higher potency (10–100× THC).
• Chemical structures change rapidly to evade scheduling; batch variability extreme.
• No quality control; contaminants (fentanyl, brodifacoum) reported.

Acute Effects

• Neuropsychiatric: Agitation, psychosis, hallucinations, paranoia, catatonia, seizures.
• Cardiovascular: Tachycardia, hypertension, MI, stroke, arrhythmias.
• Other: Hyperthermia, rhabdomyolysis, AKI, vomiting.

Duration

Onset: minutes (smoked). Peak: 15–30 min. Duration: **2–6 hours typically**; up to 12+ hours with high-potency analogs or large doses. Prolonged psychosis may persist days-weeks.

Risks

• Addiction, withdrawal syndrome.
• Acute kidney injury (specific analogs).
• Severe bleeding (brodifacoum contamination).
• Death from cardiovascular collapse, seizures, trauma during psychosis.

Management

• Supportive: benzodiazepines for agitation/seizures, cooling, IV fluids, cardiac monitoring.
• No specific antidote.
• Psychiatric follow-up for persistent psychosis.

Bottom Line

Synthetic cannabinoids are **not safe alternatives** to cannabis. Avoid use; seek emergency care for adverse reactions.