Phencyclidine, more commonly known as PCP or “angel dust,” is a potent hallucinogenic drug with a long and complicated history. PCP was originally developed as a surgical anesthetic in the 1950s; however, the use of this drug for surgical purposes was discontinued after the negative psychological side effects became obvious (agitation or combativeness, paranoia, anxiety or panic, hallucinations).
Today, PCP is classified as an illicit drug with a high potential for abuse, and its effects on the brain and body can be both intense and long-lasting. One of the most commonly asked questions about PCP is how long it remains in a person’s system.
Whether you need to know for an upcoming drug test, treatment planning, or concern for your own or someone else’s substance use, the following article will help you understand how long PCP persists in the body and factors that can affect how long it is detectable.
What Is PCP?
Phencyclidine (PCP) is a dissociative drug that distorts one’s perception of sight, sound, oneself, and their environment, creating an experience of detachment or being “disconnected” from reality.[1] PCP works predominantly on the central nervous system (CNS), which is made up of the brain and spinal cord. The drug works by blocking certain receptors in the brain used to regulate perception, mood, and cognition.[2]
According to the National Institute on Drug Abuse (NIDA), PCP is smoked, snorted, swallowed, or injected.[3] How the drug is administered does affect how long it takes for you to start feeling its effects. However, the method used to administer PCP does not greatly change how long it remains in your body.[4]
The Drug Enforcement Administration (DEA) has classified PCP as a Schedule II drug.[5] This means it has a high potential for abuse, which could result in the development of severe psychological or physical dependence, and has limited accepted medical use under very tight restrictions.
Effects of PCP
In order to answer the question of how long PCP is detectable, it helps to explain how the drug works and what the drug does to the human body.
The effects produced by PCP are largely dependent upon the dose that the user takes. At lower doses, users may experience mild dissociation, euphoria, numbness, and some distorted perception of time and space. At higher doses, users may experience many other, more serious, and dangerous effects.
Possible short-term effects caused by the use of PCP include:
- Hallucinations and distorted sense of reality
- Extreme agitation or aggression
- Elevated blood pressure and rapid heart rate
- Numbness and loss of motor coordination.
- Slurred speech and disorientation
- Psychosis – a long-term state with symptoms such as hallucinations (seeing, hearing, or feeling things that are not there), delusions (false, unshakable beliefs), and disordered thinking and speech.
It is more common for users to experience adverse effects at higher doses. These adverse effects can include: seizures, respiratory depression (slowed or shallow breathing that leads to a lack of oxygen), coma, and death.[6]
PCP is a very dangerous drug because of the dissociative state it produces, which could result in erratic and self-destructive behavior while under the influence.
The Half-Life of PCP
Half-life refers to how long it takes to eliminate half the concentration of a drug in your body.
PCP has a relatively long and variable half-life of about 7–46 hours.[7] The wide range is due to individual factors such as a person’s metabolism, body composition, and frequency of use. This is also why withdrawal symptoms from PCP, along with psychological effects (like cravings and mood changes), can continue long after the acute phases of intoxication.
How Long Does PCP Stay in Your System?
Detection times for PCP will vary depending on the type of test used and the individual factors mentioned above.[8] Here is what the research and standard clinical guidelines indicate for each testing method.
| Testing Method | Detection Window |
| Urine | 7–14 days (up to 30 days in heavy users) |
| Blood | 1–4 hours (up to 24 hours) |
| Saliva | 1–10 days |
| Hair | Up to 90 days |
Urine Tests
Urine testing is the most common method used to detect PCP use and is the standard for most workplace drug screenings and pre-employment screening panels.
PCP can stay in urine between 7–14 days after casual or moderate use. In heavy or chronic users, it can persist for 30 days or more. The long detection window is because PCP is a lipophilic drug, which means it binds to the body’s fat tissue. As fat is burned over time, the PCP metabolites are slowly released into the bloodstream and eventually excreted in the urine, which extends the detection window.
Blood Tests
Blood tests detect the active form of PCP rather than the metabolites, making them very useful for detecting recent use.
Depending upon the amount consumed, PCP will be detectable in the bloodstream from 1–4 hours. At heavy use or at high doses, it can stay in the blood as long as 24 hours. Blood tests are not typically used for drug testing as they are invasive and have shorter detection times, but they are often used in emergency medical and legal situations.
Saliva Tests
Saliva tests (also called swab tests) are non-invasive methods of testing drug use and have moderate detection times. PCP can be detected in saliva from 1–10 days after the last use, depending on frequency and amount of use. Saliva tests are increasingly used in roadside and workplace testing due to the ease of obtaining the body fluid sample.
Hair Tests
Hair follicle testing has the longest detection time of any standard drug test. Since drug metabolites are incorporated into the hair shaft as it grows, a standard hair sample of 1.5 inches of hair can detect PCP for a period of approximately 90 days. Hair testing is generally not done for routine pre-employment drug tests, but is frequently used in legal matters, custody situations, and some treatment programs where drug use needs to be monitored.
Factors That Affect How Long PCP Stays in Your System
There are several factors that can influence the rate of elimination of PCP from your body, which include:
- Frequency and amount of use. Higher frequency of use and consuming larger quantities of PCP will result in more accumulation of the drug in fat tissue, making elimination take longer for chronic users than for infrequent users.
- Body fat percentage. Since PCP is lipophilic, users with higher body fat percentages will tend to retain PCP longer than those with lower body fat percentages. The fat tissue functions as a reservoir for PCP, and metabolites will be released from the fat tissue over time.
- Individual metabolism. Your metabolism affects how long PCP stays in your body. Factors such as age, liver function, genetics, and overall health can contribute to your metabolic rate.
- Hydration and kidney function. PCP and its metabolites are eliminated from the body primarily via the urine. Proper hydration can help support kidney function and can mildly contribute to how efficiently PCP is eliminated; however, proper hydration will not significantly alter the period of detection. Excessive water intake to force elimination is not effective and can be dangerous, even life-threatening.
- Health conditions. Certain health conditions, particularly those that adversely affect the kidney and liver, can slow the body’s ability to metabolize and eliminate PCP, prolonging drug elimination.
- pH levels. Research has shown that urine pH affects PCP excretion. Acidic urine promotes faster excretion of PCP, while alkaline urine slows it. This is why some clinical detox protocols have historically used acidification strategies, though this approach carries its own risks and should only be managed by medical professionals. Commercial kits to force drug elimination are not effective.
False Positives and PCP Drug Tests
In some cases, some drugs can cause false-positive results for PCP in an initial immunoassay drug screen.[9] These can include:
- Certain antidepressants
- Antihistamines
- Dextromethorphan (found in many over-the-counter cough medications)
All preliminary positive results should be confirmed through a more specific test prior to taking any action based on the test result.
Your Freedom Starts Here
If you or a loved one is using PCP, help is available. The Freedom Center offers personalized, compassionate addiction treatment in Maryland for those who wish to make a change.
