Chapter 3: How drugs work in the body and on the mind.
Drug administration and absorption
- Oldest and easiest way of taking drugs
- Safest method of drug admin
- Begins after 5 mins after ingestion, but full ingestion is complete 6 – 8 hours.
- Weakly acidic drugs are absorbed faster
- If drugs are lipid soluble
- When consumed orally, you usually have to take higher doses.
- Directly into the bloodstream
- READ the 3 types of injection from textbook (Pg 62-63)!!
- If injected into a muscle = high absorption
- Can be vapour or smoked
- Is the fastest method of drug admin
- Second easiest way of taking a drug
- Reaches the brain faster than any other way, 5-8 seconds
- Can cause lung damage
- When the drug passes through membranes outside of the body
- Eg: nicotine patch, birth control patchs
- Whne ppl snort cocaine it sticks to the mucus and goes through the nasal membrane
- Rectal suppository – absorped from the anus.
- Oral is the slowest method of drug admin
- Second slowest – absorption
- Third slowest – injection, the most dangerous b/c ppl can inject high doses at a time.
- Fastest – inhalation Drug Elimination
Biotransformation - drugs are broken down to smaller pieces called metabolites
- Usually drugs are water soluble, they are eliminated by urine, sweat and exhalation.
- 1. Urine
- 2. Exhaled breath
- 3. Sweat
Elimination half-life - amount of time it takes to reduce a drug by 50%
- Nicotene = a few hours
- Cocaine – a few hours
- Marijuana – several days, can take a month to eliminate
Factors determining drug impact
- Delivery and timing
- Latency period – amount of time it takes for the drugs to have its affect on the body
and is dependent on method of admin.
- When you put two drugs together, both the drugs will be expressed in the body and
have increased affects of the drugs.
- Additive – Eg: Advil cold and sinus has painkiller affects and deconjestion affects
when you take. So it has the same affects if you had taken them separately.
- Such as alcohol with sleep meds
- Lanoxin (heart meds) with bran and oatmeal – increa