An old, cheap prescription anti-sickness medicine, well established for preventing the nausea and vomiting that follow cancer treatment and surgery. It also switches on a nicotine-sensing receptor, which has driven testing for pain, thinking and attention. Dosing stays at 5 mg; headache, slowed bowels and drowsiness are common. Never tested in healthy adults or beyond a few weeks. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Corrected QT interval | Below 440 ms in men, below 460 ms in women | Sets the electrical reserve before an additive drug effect matters |
| Serum potassium | 4.0–4.5 mmol/L | Low potassium is the main amplifier of drug-induced electrical delay |
| Serum magnesium | 2.0–2.4 mg/dL | Magnesium stabilises cardiac repolarisation and is commonly depleted |
| CYP2D6 metaboliser phenotype | No numeric target exists — measured metaboliser status is tracked against the normal-metaboliser reference | Determines whether a fixed 5 mg dose delivers normal, sevenfold or half-normal exposure |
| Alanine aminotransferase and aspartate aminotransferase | Below 25 U/L in men, below 20 U/L in women | Hepatic clearance means impaired liver function raises exposure |
| High-sensitivity C-reactive protein | Below 1.0 mg/L | Tracks the systemic inflammatory signal the nicotinic action is proposed to damp |
Cadence: Electrocardiogram and electrolyte panel repeated at 48–72 hours for multi-day intravenous courses; electrolytes and liver enzymes every 3–6 months for repeated oral courses; electrocardiogram repeated whenever another QT-prolonging medicine is added