How Long After a Dose Can Opioids Be Detected on a Drug Test?

Although the effects of the substance may have already worn off, it may still be detectable for hours, days, or weeks after the most recent dose. In your day-to-day life, you may eventually encounter a drug test. When that time comes, it pays to be prepared, so here are the ins and outs of opioids, how they differ, and how they’re tested.

Methods of Administration

The amount of time that a drug stays in your system will vary depending on how it is taken. Let’s take a look at some of the most common ways of taking drugs, how they work, and how they may affect a drug test.


If a drug is taken orally, then there is a good chance that it will stay in your system for a longer time. When you take a pill or eat a drug-laced food item, your stomach needs to digest it. Digestion is a slow process, so naturally, the drug will be released into your bloodstream over a longer span of time, and it won’t stop being released until it is completely digested. From that point, you still have to wait until the drug is fully metabolized.


When a drug is injected, it immediately enters the bloodstream and starts being metabolized right away. Because of this, a drug that is injected will usually become undetectable in a quicker span of time than the same dose administered another way. Still, this is not an endorsement of intravenous injection by any means. Intravenous injection holds a much higher risk of overdose, disease transmission, infected wounds, and other negative health outcomes.


When a substance is heated so that the vapors may be inhaled, the heated substance travels to the lungs where it is absorbed straight into the bloodstream. Vapor may also be absorbed into the bloodstream through the mucus membranes of the mouth and throat. While the drug will become undetectable in the blood at a similar rate as if it had been intravenously injected, it may remain detectable in a saliva test for a longer time than with other methods of administration.


Also known as blowing or snorting, this method of administration works quickly by allowing your body to absorb drugs through the mucus membranes within the nose. The substances within finely ground powder quickly enter the bloodstream and reach the brain. Nasal numbness and post-nasal drip are signs that trace amounts of the substances may still be stuck somewhere inside the nasal cavity. Because of this, exposure to the drug may be prolonged for a much longer span of time since you’re basically micro-dosing for hours until the remaining substance is completely absorbed.

Individual Biology

Younger, healthier people tend to have faster metabolisms than older, less healthy individuals, so opioids are usually processed faster and will become undetectable in a shorter amount of time. The liver and the kidneys are very important when processing opioids, so any individuals with liver or kidney damage will take a longer time to metabolize their last dose to the point that the substance is undetectable with a urine, saliva, or blood test.

Dose and Type of Drug

Naturally, a larger dose will take a longer time to fully metabolize; a person’s kidneys and liver can only work so fast. Furthermore, different opioids are processed at varying rates. Fast-acting drugs like fentanyl will usually become undetectable much quicker than morphine, methadone, Oxycontin, or codeine. Generally, oral medications will stay in your system noticeably longer than other opioids.

Types of Tests


Urinalysis is among the most common drug tests available. Due to a longer detection window in most circumstances, medical professionals and parole officers prefer urine tests in routine situations. Here are the typical detection windows for common opioids when tested via urinalysis:

  • Codeine: Up to 2 days
  • Fentanyl: Up to 1 day
  • Heroin: Up to 7 days
  • Hydrocodone: Up to 4 days
  • Morphine: Up to 3 days
  • Oxycodone: Up to 4 days


When administering a saliva test, a cotton swab is inserted into the mouth, and the saliva is tested for traces of opioids and their byproducts. Typically, saliva tests are good at detecting very recent use, but some substances can be harder to detect with this method. Substances that are smoked, inhaled, or taken orally may have a longer window of detection than if the same substances were to be injected or insufflated.

  • Codeine: Up to 4 days
  • Fentanyl: Not enough data
  • Heroin: Up to 6 hours
  • Hydrocodone: Up to 2 days
  • Morphine: Up to 4 days
  • Oxycodone: Up to 2 days


Because blood tests provide the quickest results, they are most often used in emergency medical settings where results are needed as soon as possible. These tests are pricey, uncomfortable, and unpleasant, so they are not usually used by employers or parole officers.

  • Codeine: Up to 1 day
  • Fentanyl: Up to 12 hours
  • Heroin: Up to 6 hours
  • Hydrocodone: Up to 1 days
  • Morphine: Up to 12 hours
  • Oxycodone: Up to 1 days


Unless you’re applying for a job that requires a very high-security clearance, there is a very low chance that you will ever undergo a hair test. Hair tests can detect a substance up to 90 days after the last dose, but they are not very effective at determining recent use. Most standard jobs, parole officers, and medical professionals are far more concerned with detecting recent use, so you don’t have to worry about shaving your entire body just to stay safe — not that shaving would work anyway. They’ll always find a hair somewhere. Overcoming substance abuse can be very difficult, but it doesn’t have to be a solo journey. Life is short, so it should be enjoyed to the fullest extent. If you or a loved one are struggling with opioid addiction, then please call us at 833-762-3739 and take your first step towards a happier, healthier horizon.