What Do Common Drugs Do to Your Body? Effects & Testing
Evidence-based answer reviewed against SAMHSA cutoffs and FDA assay documentation · Updated September 2026
Quick answer: Every drug class has a predictable effect profile — and a predictable detection window. Understanding both helps you separate the temporary high from the long-lasting test result.
Opioids (opium, oxycodone, heroin)
Pain relief, euphoria, sedation, slowed breathing, constipation. Tolerance builds fast; respiratory depression is the overdose mechanism. Detection: urine 2–4 days (heroin 1–2), hair up to 90 days.
Stimulants (cocaine, meth)
Energy, focus, elevated heart rate, appetite suppression, euphoria. Overuse risks cardiac strain, paranoia, and psychosis. Detection: urine 2–4 days (meth up to 5), hair 90 days.
Cannabis
Relaxation, euphoria, altered perception, increased appetite. Chronic use stores THC-COOH in fat, stretching urine detection to 30+ days. Hair detection up to 90 days regardless of pattern.
Depressants (benzodiazepines, alcohol)
Anxiety relief, sedation, impaired coordination, slurred speech. Combined with opioids, they multiply respiratory depression risk. Detection: urine 2–7 days (long-acting benzos up to 30), alcohol via EtG 2–3 days.
Certified labs nationwide · Results in 1–2 days
Need a test? Order online, test same-day →People also ask
Do prescriptions count against me?
No — verified prescriptions report as negative through the Medical Review Officer. Declare medications at collection and answer the follow-up call.
Sources & further reading
- SAMHSA — Mandatory Guidelines for Federal Workplace Drug Testing Programs (cutoffs, MRO process)
- DOT — 49 CFR Part 40 procedures for transportation workplace testing
- Brahm NC et al., Mayo Clinic Proceedings 2008;83(1):66–76 — false-positive cross-reactivity reference
- FDA — drug-of-abuse test device labeling (detection window conventions)