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How Long Does PCP Stay In Your System? (Phencyclidine)

PCP (Phencyclidine), commonly referred to as “Angel Dust,” was first synthesized in the 1950s and initially approved by the FDA as an anesthetic under the brand Sernyl.  As a result of its extended half-life (approximately 3 days) and adverse psychotomimetic effects (e.g. hallucinations), it was taken off the market in 1965.  Despite its removal from the market as an anesthetic, PCP gained popularity in the late 1960s and 1970s as a common recreational drug.

The drug functions primarily by acting as an NMDA receptor antagonist, triggering dissociative effects.  In addition to its antagonism of NDMA receptors (altering glutamate levels), PCP acts as: an inhibitor of nAChRs (nicotinic acetylcholine receptors), a partial agonist at D2 receptors, and a dopamine reuptake inhibitor (DRI).  As a result of its complex effects on neurotransmission, effects of PCP intoxication tend to include: dissociation from reality, altered mood, and bizarre sensory experiences.

Unwanted effects associated with PCP ingestion include: drug-induced psychosis, excited delirium, and even brain cell death.  Since there is scientific evidence to highlight the dangers of PCP ingestion, its usage as a recreational drug has plummeted.  There are still, however, some individuals that recently quit using PCP and want to know how long the drug stays in their system before they are truly “clean.”

How long does PCP stay in your system? (Phencyclidine)

Assuming you’ve recently stopped using PCP, there’s a chance that the drug (as well as its metabolites) are still in your system.  Because PCP is highly lipid-soluble, it is known that following ingestion of PCP it is stored in fat and brain tissue.  As a result, PCP has a relatively long elimination half-life compared to other drugs, but the specific half-life duration remains unclear.

Some sources suggest that its elimination half-life ranges between 7 hours to 46 hours (with an average of 21 hours).  Assuming these sources are accurate, this means it could take you anywhere from 1.6 and 10.54 days to fully eliminate 100% of the PCP from your system.  Considering the “average” PCP half-life of 21 hours, it would take just under 10 days (9.6) for PCP to get fully eliminated.

Other sources suggest that due to PCPs slow release from lipid stores, its half life is really approximately 3 days (72 hours).  If a half-life of 3 days is accurate for PCP, you can expect that the drug will take up to 17 days for the drug to be fully eliminated from your system.  That said, since there is significant individual variation among PCP users, it can be expected that some people will retain the drug for a longer duration within their system compared to others.

  • Source: http://www.nhtsa.gov/people/injury/research/job185drugs/phencyclidine.htm
  • Source: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2859735/

Factors that influence how long PCP stays in your system

There are numerous factors that will influence how long PCP is likely to stay in your system.  These factors include things such as: dosage, frequency of usage, purity of PCP, modality of administration, and/or whether it was taken along with other drugs.  Due to the array of complex factors that influence PCPs absorption, metabolism, and excretion – it is difficult to predict an exact timeframe for clearance from your system.

  1. Individual factors

Assuming two people ingest the same dosage of PCP with the same method of administration, why can one person clear the drug from their system quicker than the other?  Speed of PCP clearance is usually related to a variety of personal factors including: age, body mass, food intake, liver function, metabolic rate, and urinary pH.

Age: It is understood that younger individuals tend to be in better health, have quicker metabolic rates, and more blood flow to the liver than elderly (individuals 65 and older).  In general, younger people are able to metabolize and excrete PCP from their system more rapidly than elderly because their bodies are usually operating with greater efficiency.  An elderly PCP user may retain the drug (and its metabolites) for longer due to health problems, slower metabolism, and inefficient functioning of the liver.

Body (Weight / Height / Fat): Realize that the amount of PCP you ingest in relation to your weight, height, and body fat could influence how quickly the drug gets cleared.  A tall/heavy individual that takes the same PCP dose as a short/light individual may be able to process and clear the drug quicker due to the fact that they have a bigger system to process more of the drug.  It is also important to consider that body fat percentage can impact clearance of PCP; the greater a person’s body fat, the longer they are likely to retain PCP.

Food intake / hydration: Eating food either prior to taking PCP or after taking it could affect absorption of the drug.  Someone who eats a large meal prior to ingesting PCP may not absorb as much of the drug, whereas someone who takes PCP on an empty stomach may absorb more of it.  The more of the drug a person absorbs, the longer it’ll take to metabolize and clear it from their system.  Level of hydration may also have a subtle effect on how quickly PCP is processed and excreted.

Genetics: It is known that PCP is metabolized within the liver, specifically by cytochrome P450 (CYP450) enzymes such as CYP3A.  Genetic variants of CYP450 can influence how quickly drugs like PCP are metabolized.  Some people have variants of CYP450 that may quickly metabolize PCP (i.e. “rapid metabolizers”), whereas others may have a variant resulting in slower metabolism (i.e. “poor metabolizers”).  The more rapidly you’re able to metabolize PCP via CYP450, the quicker you’ll be able to clear it from your system.

Liver/kidney function: If your liver and/or kidneys aren’t operating to their full capacity, you may have trouble processing and clearing PCP from your system.  Those without any liver and/or kidney abnormalities should be able to metabolize and clear PCP efficiently from the body.  However, individuals with suboptimal (or impaired) liver functionality could take significantly longer to metabolize and excrete the drug.

Metabolic rate: Your basal metabolic rate (BMR) is thought to influence how rapidly you’re able to clear a drug from your system.  Those with faster BMRs tend to metabolize and excrete exogenous substances like PCP quicker than those with slower BMRs.  While genetics has an impact on BMR – so does exercise, diet, and lean body mass.  Since those with quicker BMRs tend to have less body fat, PCP will not remain stored in fat cells for as long of a duration; the opposite is also likely.

Urinary pH: If you have a urinary pH that is highly acidic, chances are that you’ll excrete PCP more efficiently than someone with a highly alkaline urinary pH.  Renal clearance rates of PCP are substantially affected by an individual’s urinary pH.  Someone with a highly alkaline urinary pH will actually decrease their renal clearance rate (per hour) than someone with a highly acidic urinary pH.  In fact, if urinary pH is made highly acidic – renal clearance rates can increase by 100-fold.  Hence, urine is often acidified among those who overdose on PCP.

  1. Dosage + PCP Purity

In addition to individual factors, the dosage and purity of PCP ingested can influence how quickly it is metabolized and excreted.  The greater the dosage a person takes of PCP, the more of the drug will accumulate throughout their system, resulting in a prolonged clearance.  With higher doses, there’s a greater chance of more PCP getting stored within lipids (fats) throughout the body.

Since PCP is released unevenly and slowly from lipid stores, with higher doses a person increases the odds that PCP will stay in their body for a longer duration.  Your average light dose of PCP is thought to fall within the range of 3 mg to 5 mg, whereas an average dose is between 5 mg and 10 mg.  Stronger doses of PCP are considered anything over 10 mg.  Individuals that use lighter doses should clear it from their system quicker than those who use moderate or heavy doses.

In addition to the dose, it is important to consider the purity of the PCP and sourcing.  PCP is difficult to synthesize, often resulting in street formulations of the drug varying in actual concentration of PCP.  Some of these formulations may contain precursors (e.g. PCC) and/or other chemical byproducts.  For this reason it is necessary to consider the purity of your PCP and realize it could alter absorption, metabolism, and excretion rate.

  1. Modality of administration

There are many different ways in which a person can take PCP.  Some of the most common ways include: oral ingestion, smoking, intravenous injection, and intranasal insufflation.  It is important to realize that the route of administration could influence how much of the PCP dose is absorbed and how rapidly it is metabolized.

Both absorption and metabolism are thought to influence how quickly it is excreted from your system.  When PCP is smoked, it may be “lacing” another drug such as marijuana.  The full dose may not be efficiently absorbed via smoking, but the onset of action is quick (within 5 minutes) and peak effects are attained within 15 to 30 minutes post-ingestion.  If added to another drug in the form of “liquid PCP,” it is estimated that 69% will get inhaled.

It is thought that a second peak (window of absorption) will occur 1 to 3 hours after smoking.  Researchers speculate that this could be due to trapping of PCP in the mouth (for later release and absorption) or may be a result of its absorption via lungs (with slower release into the body).  If ingested orally, the plasma levels of PCP are thought to peak 1.5 hours post-ingestion.

As a result of differences in absorption speeds and delivery, the speed by which PCP is eliminated from a person’s system could vary by hours based on how they administered the drug.  The more prolonged the absorption, the longer it will take for the body to excrete PCP and its metabolites.

  1. Frequency of usage (High vs. Low)

Those who use PCP often are more likely to retain the drug in their system for a longer term than individuals who seldom use PCP.  Since PCP is stored in lipids, the more frequently a person uses the drug, the greater the amount will have accumulated within bodily lipids.  As PCP accumulates in lipids and adipose tissues of users, it continues to accumulate.

Frequent PCP users also quickly build up a tolerance to PCPs effects, resulting in the ingestion of higher doses with each successive usage.  Higher doses are also known to provoke greater accumulation of PCP within the body, making it more difficult for frequent users to eliminate the drug.  A less frequent PCP user may efficiently eliminate the drug from their system within a week, whereas a high-frequency/high dose user may be unable to clear the drug from their system for over half-a-month.

  1. Ingestion of other drugs

Simultaneous administration of PCP along with another substance may affect its absorption.  Specifically, ingestion of PCP along with an agent that inhibits cytochrome P450 3A isoenzyme (CYP3A) will interfere with the metabolism of PCP.  It is unclear as to what extent CYP450 inhibitors may affect your ability to metabolize and clear PCP; this is likely subject to significant variation based on dosage of the co-ingested drug and its specific degree of inhibition.

Some examples of potential CYP3A inhibitors include: Abilify, Ambien, Fentanyl, SSRIs, Warfarin, etc.  If you took these drugs along with PCP, it would likely slow metabolism of PCP and may result in severe contraindications.  On the other hand, certain agents known as “inducers” may expedite metabolism of PCP via CYP3A, resulting in quicker clearance.

Examples of CYP3A inducers include drugs like: Phenobarbital, Phenytoin, and St. John’s Wort.  Although these drugs can theoretically speed up the metabolism of PCP – severe contraindications may still occur.  Among most PCP users, co-ingestion with illicit drugs such as marijuana and cocaine is common; realize that these other substances could affect metabolism and clearance times.

  • Source: https://books.google.com/books/about/Pharmacokinetics_and_Pharmacodynamics_of.html
  • Source: http://www.ncbi.nlm.nih.gov/pubmed/7128004
  • Source: http://www.ncbi.nlm.nih.gov/pubmed/9152594
  • Source: http://www.ncbi.nlm.nih.gov/pubmed/7184997

PCP Absorption, Metabolism, and Excretion

Following smoking of PCP, the substance is rapidly absorbed from the lung and quickly crosses the blood-brain barrier.  If ingested orally, the substance is absorbed by the small intestine.  Oral ingestion allows PCP to be secreted into stomach acids in which it accumulates to 50-fold the extent of serum levels, followed by reabsorption by the small intestine.  Each absorbed milligram of PCP equates to an estimated blood concentration of 10 ng/ml.

Up to 90% of PCP will have undergone first-pass metabolism via oxidative hydroxylation in the liver; specifically via CYP450 enzymes (primarily CYP3A).  Hydroxylation within the liver facilitates the creation of 2 monohydroxylated metabolites and 1 dihydroxylated metabolite.  The monohydroxylated metabolites are inactive in humans, but include: PPC (4-Phenyl-4-(1-piperidinyl)-cyclohexanol) and PCHP (1-(1-Phenylcyclohexyl)-4-hydroxypiperidine).

The dihydroxylated metabolite HPPC (4-(4′-hydroxypiperidine)-4-phenylcyclohexanol) remains present in urine as glucuronide conjugates. PCP metabolites will then undergo glucuronidation for excretion via kidneys, and 9% of the active drug will be excreted.  Other minor metabolites excreted after PCP ingestion include: PCA (1-phenylcyclohexylamine) and PCAA (5-[N-(1-phenylcyclohexyl)]-aminopentanoic acid).  If smoked, the metabolites PC (1-phenyl-1-cyclohexene) and piperidine are formed.

It is thought that between 30% and 50% of a PCP dose will have been excreted within urine after 72 hours.  Approximately 19.4% of PCP will remain unchanged via urinary excretion, and 80.6% will be excreted as PCP metabolites.  An estimated 2% of a PCP dose will be eliminated via feces.  PCP levels can remain high in adipose tissue, the brain, and lipid stores throughout the body.

Since PCP has a long half-life, it can take between 2 and 11 days to be completely eliminated from the body.  Ultimately a variety of the aforementioned factors such as urinary pH, liver/kidney function, genetics, metabolism, and dosage will influence its clearance.

  • Source: http://www.nhtsa.gov/people/injury/research/job185drugs/phencyclidine.htm

Types of PCP Drug Tests

There are many modalities of drug tests that can be administered to determine whether someone has recently ingested PCP.  Due to the drug’s relatively long half-life, it is very easy to know whether an individual had used PCP.  Common ways to test for PCP include: urine tests, hair tests, blood tests, and saliva tests.

Urine tests: Among average PCP users, the drug is most likely to remain detectable in the urine for up to 7 days post-ingestion. It is estimated that the urine sample of a PCP user could contain up to 19% unchanged PCP and 30% metabolites (PCAA / PCHP).  Among heavy/frequent PCP users, it is possible for PCP (and metabolites) to remain detectable in a urine sample for up to 2 weeks post-ingestion.

Most PCP will have been excreted via the urine within 3 days, and up to 97% will have been excreted via urine within 10 days.  Even after taking a high dose, it is unlikely that PCP would remain detectable in a urine sample following 7 days (1 week).  If gas chromatography/mass spectrometry (GC/MS) isn’t used to analyze urine samples, false positives could be triggered by the presence of SSRIs, DXM, ketamine, and tramadol.

Blood tests: It is possible to first detect levels of PCP in the blood within the first hour of ingestion, and for up to 3 days post-ingestion.  Most blood tests will be able to determine whether PCP is present in the bloodstream for a period of 1 to 3 days following usage.  Blood tests are seldom preferred over urine tests due to the fact that they are more invasive, and metabolites can be detected in urine than the blood.

A blood test is typically reserved for individuals requiring hospitalization as a result of PCP ingestion.  In most cases, blood tests are best for determining whether someone has ingested PCP within the previous 24 hours.  If administered several days after ingestion, blood tests are usually unable to accurately determine whether PCP usage occurred.

Hair tests: Hair follicle analyses can be utilized to determine whether someone had used PCP over a longer duration.  If subjected to a hair test, an individual will be required to provide a hair follicle sample (usually 3 cm to 6 cm) from their head (or other area of their body).  The follicle sample will be sent to a laboratory and analyzed to determine whether PCP and metabolites (PCHP and t-PCPdiol) are detectable.

Although hair samples are unable to detect PCP if administered just a day or two after ingestion, they are effective for determining PCP usage over the past several months (e.g. 90 days).  Even if PCP is fully out of a person’s system, it is important to realize that it may linger within hair follicles.  Each new “centimeter” of hair that grows can be linked to an approximate 1 month period.  The lengthier a person’s hair, the longer the detection window via a hair sample.

Saliva tests: It is uncommon to conduct a saliva drug test to determine whether an individual has used PCP.  Saliva tests are often inaccurate and unable to detect the presence of PCP and various metabolites.  The metabolite PCHP can be detected in saliva, but is detectable for a longer duration via hair testing.

Saliva may reveal whether an individual had ingested PCP within 24 hours of ingestion.  Some sources believe it is possible to detect the presence of PCP (and metabolites) in saliva for up to 1 week post-ingestion.  Although saliva tests are relatively non-invasive and easy to administer, other testing modalities are usually preferred.

  • Source: https://www.ncbi.nlm.nih.gov/pubmed/9288587
  • Source: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2859735/
  • Source: http://www.ncbi.nlm.nih.gov/pubmed/6503222

Who could get drug tested for PCP?

Since most standardized drug tests assess for the presence of PCP, a variety of individuals are subject to PCP testing.

  • Athletes: Many collegiate and professional athletes are subject to regular mandatory drug testing. Should they have ingested PCP, it will likely show up on one of these drug tests, resulting in a potential suspension and/or ban from competition.
  • Employees: Companies will assess both prospective and current employees via regular drug testing to determine whether they’ve taken any illicit substances. If an employee had taken PCP and tests positive, they’ll likely get fired.  An un-hired, prospective employee will get turned down for a job if PCP is detected.
  • Military personnel: There are strict consequences associated with failing a drug test in the military. Should an individual serving in the military test positive for PCP, they could face harsh penalties and will be delisted.  Furthermore the individual will not receive any compensation for their services.
  • Rehab patients: Individuals in drug rehabilitation facilities are often tested regularly for a variety of drugs. Since PCP is included on both standard and comprehensive testing panels, it is likely that it would be detected if ingested.  This could mean more time spent in rehab and/or some sort of punishment.

Tips to clear PCP from your system faster

If you’ve ingested PCP and want to clear it from your system as quickly as possible, below are some tips that you should consider.  Keep in mind that effectiveness of these tips for clearance of PCP is subject to individual variation.

  1. Discontinue usage: Many users of PCP want to clear the drug from their system, but haven’t actually stopped using it. If you want to ensure that PCP (and all of its metabolites) are excreted from your body, you’ll need to stop as soon as possible. The sooner you discontinue PCP usage, the faster the drug will leave your system.
  2. Acidify urinary pH: An easy way to make sure that PCP is excreted as quickly as possible is to acidify your urine. You could consider taking acidifying agents to enhance excretion of PCP. Some studies have shown that excretion rates per hour can increase by up to 100-fold if urine is highly acidic, whereas excretion rates decrease if urine is alkaline.
  3. Metabolic inducers: Certain substances are known to speed up metabolism of the body, as well as metabolism within the liver. Taking a metabolic inducer to expedite processing of PCP in the liver could result in faster clearance. Keep in mind that you should always discuss supplements and/or drugs you’re considering with a medical professional before you take them.
  4. Hydration / Diet: It is thought that sufficient hydration along with intake of the right foods could help eliminate PCP from your system quickly. Those that are dehydrated may be unable to excrete as much of the drug via urine, and individuals that eat more food may expedite clearance of PCP. Eating healthy foods will also ensure that your body has proper antioxidants for optimal liver/kidney functioning (which will help excrete the drug).
  5. Daily exercise: Exercising on a daily basis can speed up your metabolic rate and help your body process PCP more efficiently. It will do this by optimizing blood circulation, metabolism, and will help burn fat that stores PCP. Try going for a jog each day and it may help with clearance.

Have you failed a drug test because of PCP?

If you’ve been drug tested and failed because of PCP, share your experience below.  Provide details regarding: the type of drug test, how long after PCP ingestion you were tested, dosage of PCP ingested, the route of administration, and your frequency of usage.  If you’ve been drug tested and ended up passing, did you initially think you might fail because of PCP or its metabolites?

Leave a comment discussing how long you believe PCP stayed in your system.  Did you utilize any tips or tricks to help you clear PCP from your system quicker than usual?  Feel free to mention any techniques that you believe can help eliminate PCP from the body quickly.

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{ 9 comments… add one }
  • Dacola Colemon April 14, 2016, 7:21 am

    I haven’t smoked PCP 35 days and it’s still showing positive on urine tests. I weigh approximately 215 pounds I’m 5’4 inches tall. Courts tell me it takes 4 days to get out my system, but that is not right because I literally haven’t smoked in 35 days and it’s still testing positive. What can I do to clean my system?

  • Ron June 15, 2016, 10:58 pm

    I smoked weed that was lace with PCP 15 years ago, and I’m still having the effects from it that comes and goes. Lately it’s been getting worse. I have visual distortion, and separations. I’m 34 your old and been clean ever since. I’ve been to the doctors but no one can help. I’ve been depressed and scared and don’t know what else to do. How can I rid this evil out of my body (hope it’s not to late for me) please help!?!?

  • Audrey June 17, 2016, 12:32 am

    I smoked pcp a couple times in a week span. How long will it take to get completely outta my system? I last used Sunday June 11th. Only took 3 small tokes of a cig. So how long will it take to be out my system?

  • tony June 22, 2016, 7:53 pm

    I smoked PCP a week ago and it still shows up in my urine. I thought it takes about 4 days, but I was wrong.

  • Wendy S Tucker July 8, 2016, 12:12 am

    I use to be a heavy PCP user and thank God I am free from my addiction to this drug. I have read similar information indicating that PCP will leave your system by 2 weeks. I have no idea why I am different, but whether I was using heavily or just a one time use PCP always stays in my system for at least 30 days. Even testing at 28 days it would still be detected.

    The mental addiction had been very over powering for me and it caused major problems in every aspect of my life. I am truly surprised I am still alive. Anyone struggling with this substance should definitely stop using immediately what it will do to your life is just not worth it.

  • Lashae July 27, 2016, 3:09 am

    I’ve done PCP for 6 years and stopped for over a month and still can’t pass a drug test. I don’t know what to do and I’m a heavy woman, but done other drugs and stopped and they have not shown up in drug tests.

  • Janill Perez August 27, 2016, 3:14 pm

    I’ve been a smoker for 10 + years… I quit almost 3 weeks ago, its still in my system. It takes like 2 months.

  • Ray September 20, 2016, 6:33 am

    Smoked PCP over the weekend and tonight. Will it be out of my system in 20 days?

  • Rita September 30, 2016, 4:43 am

    I haven’t used PCP since August 3 and as of the 16th of Sept I’m still testing positive. I haven’t done anything major to try and clean my system other than water, exercise, and changing my diet. I have to get this crap out of my system. Can anyone offer advice?

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