Complete dosage information for 4F-MPH — threshold, light, common, strong, and heavy dose ranges across 2 routes of administration.
Full 4F-MPH profileImportant Safety Notice
Dosage information is for harm reduction purposes only. Individual sensitivity varies greatly. Always start with the lowest effective dose and work your way up slowly. Never eyeball doses — use a milligram scale.
## Recognizing a 4F-MPH Emergency 4F-MPH overdose presents primarily as a stimulant crisis: cardiovascular overload, severe anxiety or psychosis, and potentially dangerous hyperthermia. There is no specific antidote. Because no clinical dosing guidelines exist, the threshold between "too much" and "medical emergency" is poorly defined. **Warning signs that demand immediate action:** - **Severe tachycardia** -- heart rate pounding, racing, or irregular - **Chest pain or pressure** - **Extreme anxiety, agitation, or psychotic symptoms** -- paranoia, confusion, hallucinations - **Severe akathisia** -- uncontrollable restlessness that feels distinct from normal anxiety - **High body temperature** -- the person is burning hot to touch - **Seizures** - **Severe tremors or muscle rigidity** ## What to Do **1. Call emergency services immediately.** Call 911 (US), 999 (UK), 112 (EU), or your local number. **Good Samaritan laws protect callers in most jurisdictions** -- someone's life is more important than legal anxiety. Tell paramedics exactly what was taken, the approximate dose, and when. **2. Keep them calm.** Dim lights, reduce noise, speak slowly and clearly. Do not physically restrain them -- struggling worsens cardiovascular strain and hyperthermia. **3. Cool them down** if they are overheating. Move to a cool environment, apply cool water to neck, armpits, and groin. **4. Do not give additional stimulants** or try to "counteract" the effects with other substances. ## Clinical Reference In the Papa et al. (2019) intoxication case, the patient (blood concentration 32 ng/mL, urine 827 ng/mL) required **IV diazepam** for sedation and was discharged after two days with prescriptions for **promazine** (antipsychotic) and **quetiapine** (atypical antipsychotic). Symptoms persisted for approximately one week. Post-mortem concentrations in the Shoff et al. (2019) fatal case were 0.012-0.05 mg/L in blood. Hospital treatment is supportive: **benzodiazepines** for agitation, seizures, and hypertension. Active cooling for hyperthermia. Cardiac monitoring. There is no reversal agent.
A common insufflated dose of 4F-MPH is 8–14 mg.
The threshold dose for 4F-MPH via insufflated is approximately 5 mg.
4F-MPH typically lasts 3–6 hours via insufflated.
4F-MPH can be taken via insufflated, oral. Each route has different dosage ranges and onset times.
