There is one common thing between foods, medicines, other substances and alcohol. Our body needs to "process" them accurately before they get out of our system. This includes DRUGS too.
The question is how long does the effect of drugs last? Well, it could be hours, days, or weeks. One thing is important to bear in mind - the processing of the drugs in our system involves the participation of many organs and systems: digestive and respiratory, liver and kidneys. So it isn't really easy. Human body is pretty unique, in every way.
# It goes without saying that the person who ingested drugs (by smoking, through injection or swallowing it in pill form) have drugs enter the body system via the blood stream.
How to get the drug out of your system could be your next question. Your rate of metabolism plays an instrumental role. Those with a VERY HIGH METABOLISM are likely to get rid of drugs faster (much faster) than those with a slow metabolism.
# The interesting thing is that drugs aren’t just in-and-out of our body. They can be detected (when in our body) by testing out four things - our breath, blood, saliva, urine or hair.
Drug Detection Process
# Usage patternThis is where the amount and frequency of the drug becomes the judging parameter. Single or small drug doses are generally not detectable as compared to chronic or long-term use.
# Metabolic RateDrug-takers who have slower body metabolism are prone to longer detection times.
# Body MassAs goes the principle, metabolism in humans slows with increased body mass. This leads to longer detection time.
# Physical Activity Individuals who are physically inactive and have a high % age of body fat in relation to total body mass are prone to a longer detection time (due to the increased amount of metabolites stored in their fat cells).
# AgeHuman metabolism slows down with age and this is a fundamental and a well-accepted rule.
# Overall HealthHuman metabolism slows down during drug intake. This can result in a longer detection time.
# Drug Tolerance
Once tolerance to a particular type of drug is established, drug users have faster metabolizing rate of a drug. This leads to shorter detection time.
# Urine pHThis can have an impact on drug detection. Highly acidic urine leads to shorter detection time.