All drugs have different rates of action and are eliminated from the body at different rates. Actual elimination rates will vary depending on a number of factors, including the half-life of the drug, the mode of administration, how much of the drug the person has taken, the length of time and the regularity with which the person took the drug, and individual factors that vary from person to person, such as metabolism, gender, weight, and so forth. This article looks at the general elimination times for many popular drugs of abuse (the time it can be detected in the urine).
Alcohol is the most commonly abused drug in the United States. Chronic alcohol use can lead to physical dependence, addiction, and serious health issues. There is no stated half-life for alcohol in the body. The reported average amount of pure alcohol that a person can metabolize per hour varies greatly depending on the source, but is generally quoted as being 0.25-0.60 ounces of pure alcohol per hour. Again, this rate will vary among people due to a number of variables.
However, it should be noted that “pure alcohol” does not refer to the number of alcoholic beverages one drinks. It would take about 20 ounces of regular beer consumption to be the equivalent of one fluid ounce of pure ethyl alcohol. If a person drinks four 20-ounce beers at a baseball game, it would take the person over 6.5 hours to metabolize the alcohol at the rate of 0.6 ounces per hour, which explains why many people who drink heavily in the evening wake up intoxicated.
The detection time for alcohol via urine analysis will vary depending on the individual’s blood alcohol concentration, but appears to be anywhere between 18-24 hours.
Narcotic drugs are derived from the poppy plant or synthetic analogs of opium. These drugs were developed for the control of pain and also produce significant feelings of euphoria. They are highly addictive and possess a high potential for the development of physical dependence. These drugs include:
- Heroin: The half-life of heroin is about six hours. On average, heroin can be detected in one’s urine for about 2-4 days (average of three days).
- Morphine: The half-life of morphine is reported to be anywhere from 1.5 to 7 hours and can be detected in one’s system for about 2-4 days (average of three days).
- Codeine: The half-life of codeine is about three hours (2.9), and it can be detected in urine for about three days.
- Hydrocodone (the narcotic medication in Vicodin and Lortab): The half-life of hydrocodone is about four hours (3.8), and it can be detected in the urine for about an average of three days after use.
- Hydromorphone (Dilaudid): The half-life for intravenous administration is about 2-3 hours, and it can be detected in the urine for up to three days.
- Oxycodone (OxyContin): The half-life is about 4.5 hours, and it is detectable in urine for about 2-4 days, with an average of three days.
Stimulants were designed to improve attention and focus, help people stay awake, and provide stimulation to individuals with illnesses or disorders that made them lethargic. Some were even designed to assist in the treatment of depression. Stimulants include:
- Cocaine: Cocaine has a relatively short half-life that may be less than an hour to a full hour. Typically, cocaine is eliminated from the system very quickly and may only be detectable in urine for a day or two. Depending on the route of administration and the amount taken, it may even be undetectable in less than 24 hours.
- Amphetamine (Ritalin, Adderall, etc.): Amphetamine half-lives vary but average around 8-11 hours. Typically, they can be detected in urine up to three days.
- Methylenedioxymethamphetamine (MDMA, Ecstasy): With a relatively short half-life of about 7 hours, it is detectable in urine for up to two days in most cases.
Marijuana receives quite a bit of attention in the United States due to attempts to legalize it and to establish validity to its use as a medicinal herb. The active ingredient in cannabis is delta 9-tetrahydrocannabinol (THC), although there are a number of other chemical components in cannabis. There are varying reports regarding the half-life of THC, which appears to be about 30 hours; however, since it is lipophilic, it is slowly eliminated from the body. The ability to detect the drug in urine samples will vary depending on usage.
- For a single use with no previous use, cannabis is detectable in urine samples for about three days.
- For someone who uses marijuana moderately (defined as four times per week), it may be detectable in urine for five days.
- Someone who uses marijuana daily may have detectable traces of the urine for up to 10 days.
- Individuals who use marijuana regularly as chronic users may have detectable traces of marijuana in their urine for 30 days or more.
Phencyclidine (PCP, angel dust) is a dissociative drug, which is a type of hallucinogenic that distorts perception. The average half-life of PCP is about 21 hours (range of 7-46 hours). It appears to be detectable in urine for up to eight days, but in chronic users, it may be detectable for up to 14-30 days or more.
For most drugs, their presence is detected by either urine analysis or by analysis of blood. Most of the available information on the elimination of blood is given in urine analysis, and one can find discrepant information in different sources regarding the length of detection for specific drugs using urinalysis. The figures presented in this article represent average times that the drug can be detected in the urine; however, just because a drug may not be detected in the urine does not mean that it is totally eliminated from the body. For some drugs, it may take a considerable length of time before the drug is completely eliminated from a person’s system.