Drug DUI
Drug DUI in Pennsylvania.
Pennsylvania has zero tolerance for THC and Schedule I substances — any measurable amount in your blood is enough for a controlled-substance DUI. Prescription meds count too, if the state can prove impairment. Here's how drug DUI works, and how it's defended.
Two theories, one charge.
Pennsylvania prosecutors charge drug DUI under two subsections of 75 Pa.C.S. § 3802(d): the zero-tolerance metabolite theory for Schedule I substances, and the impairment theory for any drug — prescription or otherwise. Both are sentenced at the Highest BAC tier, so the penalties are identical to the harshest alcohol DUI.
§ 3802(d)(1) — Zero tolerance
Any measurable amount of a Schedule I substance or its metabolite in your blood — THC, cocaine, heroin, MDMA, LSD, psilocybin. No proof of impairment required. THC metabolites can linger for days or weeks after legal use in another state.
§ 3802(d)(2) — Impairment
Any drug — prescription or otherwise — that impairs your ability to safely drive. Xanax, Ambien, opioids, Adderall, muscle relaxers, and (for medical marijuana patients) THC. Requires state to prove actual impairment through blood testing plus DRE or officer observations.
Penalties.
Drug DUI is sentenced at the Highest BAC / controlled-substance tier — the harshest of Pennsylvania's three tiers. A first offense carries 72 hours mandatory minimum jail, $1,000–$5,000 fine, 12-month license suspension, and a 1-year ignition interlock. See the full PA DUI penalties guide for second- and third-offense exposure.
Medical marijuana & the Stone defense.
Under Commonwealth v. Stone (Pa. Super. 2024), registered medical-marijuana patients cannot be prosecuted under the zero-tolerance § 3802(d)(1) subsection. But prosecutors regularly charge § 3802(d)(2) instead — the impairment theory — which still applies. Bring your card and your medical records to your consultation.
Defenses to a drug DUI.
- · No probable cause for blood draw (Birchfield / Franks)
- · Blood-draw warrant defects
- · DRE evaluation flaws (12-step protocol violations)
- · Metabolites present without active impairment
- · Medical marijuana registration (Stone defense)
- · Valid prescription defense (§ 3810 for Rx meds)
- · Chain-of-custody problems with blood sample
- · Officer's impairment observations contradicted by video
FAQ
Frequently asked questions.
Common questions about drug DUI, marijuana DUI, prescription-drug DUI, and defense in Pennsylvania.
Pennsylvania has a zero-tolerance rule for Schedule I substances under 75 Pa.C.S. § 3802(d)(1). Any measurable amount of THC or its metabolites in your blood — even from marijuana used legally in another state days earlier — is enough to charge you with drug DUI in the Highest BAC / controlled-substance tier.
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