What is Pharmacology?

During the revision lecture, the unit coordinator told us not to assume that there wouldn't be a short-answer question on Lecture 1. And then I realised that I hadn't blogged about it. I thought I was done blogging about pharmacology, but apparently not!

Define the term “pharmacology” & the scope of the discipline

Pharmacology is essentially the study of how drugs and other biologically active substances affect the body. We don't worry so much about how drugs and so forth are actually prescribed, that's pharmacy's job.

Show awareness of the importance of plant-based medicines to the historical emergence of pharmacology, identifying 3 drugs that came from botanical sources

Originally we used plants as medicine due to the presence of many bioactive compounds.

One of the most well-known examples of a modern drug that originally came from a plant is aspirin. Aspirin originally came from willow bark, used as far back as ~200AD in Ancient Rome. In 1828 Büchner isolated salicin, the active component of willow bark. In 1897, aspirin, or acetylated salicylic acid, was patented and synthesised by the drug and dye firm Bayer.

A lesser-known example of a drug that came from a plant is atropine. Atropine originally came from deadly nightshade, a.k.a. belladonna. "Belladonna" actually means "beautiful woman," and the name came about because it can cause rosy cheeks and dilated pupils, which people thought was beautiful. (It does eventually cause death though, so there's that.) In 1831 Mein isolated atropine from belladonna, and in 1867 it was found to block cardiac vagal stimulation. (Atropine blocks muscarinic cholinergic receptors, as mentioned in my post about the autonomic nervous system.)

A third example is artemisinin, used to treat malaria. In 340AD, Sweet Annie (Artemisia annua) was used by Ge Hong to alleviate fever. In 1596 another Chinese herbalist, Li Shizhen, reported using it to treat malarial fever. It wasn't until the 1970s that the active ingredient (artemisinin) was isolated, however. One of the scientists working on this discovery, Tu Youyou, won a Nobel Prize for her work.

Appreciate how rising awareness of the limitations of plant-based medicines drove the growth of modern pharmacology

Plants are great, but they aren't perfect. For example, it's very hard to determine how much of an active ingredient you have in a plant. There may also be other compounds in the plant that might interfere with the activity of the active ingredient. Combined, these make it difficult to test drugs and determine a safe dose.

Another limitation of using plants is that you're limited to what you can find in nature. With technology, you can tweak molecules around to make drugs that are safer and/or more effective. So next time someone comes up to you saying "why take nasty synthetic aspirin when you can just chew on some lovely natural willow bark?" you've got a few things that you can yell right back at them.

Understand how 3 different classes of names are commonly assigned to drugs.

Drugs have at least three different names. They have a chemical name, a generic name and one or more brand names.

The chemical name of a drug is simply the name given by IUPAC. These are extremely descriptive, but are often quite a mouthful. For example, if you have depression you might be prescribed some (S)-1-[3-(Dimethylamino)propyl]-1-(4-fluorophenyl)-1,3-dihydroisobenzofuran-5-carbonitrile. Have fun asking the chemist for a refill of your (S)-1-[3-(Dimethylamino)propyl]-1-(4-fluorophenyl)-1,3-dihydroisobenzofuran-5-carbonitrile, though.

The generic name is a much simpler name given to the drug molecule that sounds somewhat sophisticated and classy, but not catchy enough to be a brand name. Normally they have prefixes or suffixes that are related to their function- for example, all of the penicillins end with -cillin. Just in case you were curious, (S)-1-[3-(Dimethylamino)propyl]-1-(4-fluorophenyl)-1,3-dihydroisobenzofuran-5-carbonitrile is also known as escitalopram. I still have no idea if I'm pronouncing it correctly (I've heard three different pronunciations of that name, two from the same person), but at least it's a lot easier to pronounce than the chemical name.

Finally, drugs have a brand name that sounds kinda catchy so that it sticks in people's minds. For example, paracetamol is often sold as Panadol, and escitalopram is often sold as Lexapro. After the drug is off its patent, other companies can sell the same drug under different brand names. For example, Lexapro is also sold under the brand name Lexam (they kept the first four letters the same, how original).

Show a basic appreciation of the importance of “pharmacokinetics” and “pharmacodymanics” to understanding the effects of drugs on the human body.

Pharmacodynamics is what a drug does to the body, and pharmacokinetics is what the body does to the drug. For more information, just read all of my other pharmacology posts :P