An old anesthetic that at low doses shifts mood, suicidal thinking and pain within hours rather than weeks, in people for whom standard treatments have already failed. How large the effect really is remains unsettled. Supervised, spaced courses were tolerated; frequent heavy use damages the bladder and bile ducts. Indefinite ongoing use in healthy people is untested. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Resting blood pressure | Below 120/80 mmHg before each session | Ketamine raises it transiently |
| Resting heart rate | 50–70 bpm | Same sympathetic surge raises it |
| ALT | 10–26 U/L in men, 8–22 U/L in women | Detects liver cell injury reported with heavy use |
| ALP and GGT | ALP 50–100 U/L; GGT below 20 U/L in men, below 15 U/L in women | Cholestatic bile-duct injury is the pattern seen with ketamine |
| Total bilirubin | 0.3–1.0 mg/dL | Completes the cholestatic picture alongside the bile-duct enzymes |
| Urine dipstick: blood, protein, leucocytes | Negative for all three | Earliest detectable sign of bladder lining injury |
| Serum creatinine with eGFR | eGFR above 90 mL/min/1.73 m² | Upper-tract obstruction follows advanced bladder disease |
| PHQ-9 score | Below 5, or at least a 50% fall from the individual's own baseline | Defines response and remission objectively |
| CADSS score | No established target; track the peak against the individual's own first session | Quantifies dissociation so escalation can be detected |
Cadence: Baseline liver panel, kidney function and urine dipstick within two weeks of starting. Blood pressure and heart rate every 10 minutes per session until baseline returns. Symptom scores at 24 hours after the first dose, then weekly through induction. Urine dipstick and liver enzymes at 3 months, then every 6 months while dosing continues, and immediately if urinary symptoms appear.