Hormones 2016

Pharmacodynamics
Pharmacodynamics
The study of the actions of the drugs and their effects is called
pharmacodynamics. Before a drug can be effective, it must be absorbed
and distributed throughout the body. Drugs taken orally may be absorbed
by the intestines at different rates, some being absorbed rapidly, some more
slowly. Even rapidly absorbed drugs can be prepared in ways that slow the
degree of absorption and permit them to remain effective for 12 hours or
longer. Drugs administered either intravenously or intramuscularly bypass
problems of absorption, but dosage calculation is more critical.
Pharmacokinetics
Ive been asked what ’Pharmacokinetics’ is, so here goes.
The term pharmacokinetics is derived from the Greek words "pharmakon"
meaning drug and "kinesis" meaning motion, and can therefore be defined
as the science which deals with drug movement in the body. It is concerned
with the rate at which drug molecules cross cell membranes to enter,
distribute within and leave the body, as well as the chemical changes which
they are subject to within it. Pharmacokinetics therefore deals with four
vital processes;
• drug absorption,
• distribution,
• metabolism
• and elimination (Cahill, 1994)
Or very loosely "what your body does to the drug itself"!
Photosensitivity of the skin
Short-term damage to the skin from ultraviolet light (i.e. sunlight) can occur
from photosensitivity reactions. These are not uncommon and are mostly
caused by interaction of the sun with medications some of which have been
mentioned already. Many of these reactions, experienced as sunburn-type
symptoms, can be avoided by taking extra care to minimise sun exposure.
Safety in the sun should include -
• Wearing protective clothing - loose fitting, tightly woven, dark clothes.
Also a hat, preferably with a wide brim, and it has been found that a
hat with a 4cm brim will reduce the ultraviolet rays by 50% (Hughes
and Van Oulsen, 2001).
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Version 2016.3576– – Document LATEXed – 1st May 2016
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