Sunday, 13 February 2011

Pharmacodynamics and Pharmacokinetics

David returned this week to discuss Pharmacodynamics and Pharmacokinetics, then to help us with our first Alcohol Tincture.

Pharmacodynamics is the specific act of drugs on the body.

Pharmacokinetics is the movement of drugs through the body.
- absorption
- distribution
- metabolism
- elimination

Experiment: Tracking caffiene through the body.

What can effect absorption of drugs within the body?
- heavy meat eater
- the higher the volume of tea or coffee drank will bind the microvilli (the tannins will bind the proteins)
- the overall state of the digestive tract
- inflammation, especially problems with peristalsis, ulcers or constipation.
- age of the patient - things get slower with age
- particular types of food you're eating at the time - blue cheese and mould are known to impact on drugs taken (dependent on the drug). Some drugs are to be taken with or without food, as the action of the drug can be altered, also the dosage can be altered. Herbal medicine practice is especially concerned with this, as the overall effect and dosage can be greatly altered.
- alcohol irritates the digestive tract - causing faster absorption. Water and soluble fat's (lipids) also have similar effects, both having faster absorption times than alcohol, but they are less potent.
- the state of the circulation - is the circulation getting to all the villi?
- are all the digestive enzymes in order - patients with celiac's disease or lactose intolerance can be deficient in some digestive enzymes e.g. insufficient bile to breakdown and secrete fats.
- probiotics - mainly found in the colon - overall state of the microflora, which can be greatly effected by the diet. Food allergies can also effect the state and variety of the microflora - Herbal medicine's can balance out the state of the tract, whereas orthodox medicine only knows to remove bits of the digestive tract instead of trying to balance it out.

What can effect the distribution of drugs throughout the body?
- blood pressure
- circulation throughout the body - broken veins, varicos veins, cold hands and feet etc - any impairment will alter the blood flow and subsequently hamper the drug getting to the target.
- blood constituents - patients with diabetes have higher sugar concentrations in their blood, which leaves them with "gloopy" blood, which will hamper the diffusion in and out of the blood stream.
- "mild" heart failure - a failure of the organ to do the job 100%

Autoimmune diseases - asthma, lupis, rheumatoid arthritis. Orthodox medicine tries to control these with steroids etc, to shut down the immune system.
Our immune system is primed to recognise proteins - during development it learns to recognise self proteins and non-self proteins. The immune system is under constant assault from constant changes in food - fluorine in water, changes in proteins in milk through pasturisation and changes in protein molecules in wheat, to make the bread lighter and fluffy instead of heavy and brick-like.

- other drugs and fluids in the blood e.g. fruit juice
- the state of the liver, portal circulation - volume of blood drawn through the liver. Fats bypass the liver, and are absorbed directly into the lymph system.

The lymphatic system

In Traditional Chinese Medicine, accupuncture is used in line with the lymph system, it feels like the needle is being "sucked" in, when it hits the right spot.
- beating the sternum activates the thymus, the size of which decreases as you get older.
- the lymph fluids are a fatty yellow fluid.
- the lymph system is involved primarily in defence - it really is the immune system.

Psychoneuroendoimmunology - main keys in the lymph system.

- points of infection, all concentrates to the area (e.g. ear) - phagocytosis to lymph system to destroy and drain the infection.
- breast cancer/hormonal fluxs - pre-menstrual cycle etc - moveable lymph nodes is ok, hardened lump is more worrying.
- muscles drive the lymph movement - using the MBT's helps keep the muscles moving fluidly, heels de-activate the calf-pump. Pregnancy can cause varicos veins, too much pressure on the pump, the vein collapses and blood pools.
- you can remove the spleen and live without it, however it can cause slight immune system inconveniences, such as coughs and colds.

In Traditional Chinese Medicine, the chi flow is vital, a smooth flow is vital to perfect health, blockages can lead to ill health - tapping and breathing exercises, alter the ying and yang, to correct flow problems. There are three sources of chi:
1. Constitutional chi, vital force you get when you're born - "jing" - largely stored in the kidneys,
2. Prana - transfer of chi from the air through the lungs.
3. Food

What can effect the metabolism of drugs in the body?

Experiment: Caffiene to the brain, effected the neurotransmitters, now breaks off and moves to the liver to be metabolised.

- what you do in your life.
- age
- hypericum, St Johns wort, pineapple juice, blue cheese, alcohol - all effect how the liver is working - herbal medicines are holistic healers not as specific as orthodox medicine (theurapeutic range). Too much pineapple juice could technically be endangering your life - potentially half a carton or one carton a day - depends on the quality and state of the liver - it effects the enzymes in the liver. Pineapple juice slows down the process, if it hangs around the liver too long it can go back into the blood, technically doubling the dose.

Caffeine make the enzymes break up, making them water-soluble so as to be absorbed by the kidneys.

Liver conjugates - breaks down and attaches water-soluble components so it passes through the kidneys to pass out of the urine.

Finally, the last key step is elimination from the body.

The drug will travel to the kidneys, which is the primary route for drug elimination.

However, Herbal Medicines have several routes for elimination, the digestive tract, kidneys, lungs, skin and the monthly menses which is used for cleansing and elimination.
Essential oils are eliminated through the lungs, for example, garlic - even a garlic-based foot rub will be noted on the breath.

The Chinese have, in the past, called whites "smells like a cow" - due to our high dairy consumption. Every race has a different smell, which you will naturally know and recognise.

Smells differ throughout life - we become less sensitive to smells as we get older, children are very good are using their sense of smell.

Experiment: Tracking caffeine through the body.

Caffeine has a half-life of 5.7 hours, meaning it takes around 12 hours to leave the system completely. However the noteable effects of the caffeine may have been lost many hours before.

We have looked at the basic process of a drug, in this case caffeine. travelling through and being eliminated from the system. This is the base route that all drugs will take through the body, the time it takes to eliminate a singular drug from the system is however very variable on the drug, the quantity, the overall state of your system and the half-life of the drug involved.

This concluded the morning session.

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