C6h Analgesics

a drug is an externally administered substance which modifies or affects chemical reactions in the body

Analgesics are drugs used to reduce pain (painkillers)

e.g. • aspirin;• paracetamol;• ibuprofen.

Most medicines are sold in a shop where there is a trained pharmacist.

Chemicals required for making analgesics must be very pure.

Higher only You need to be able to:

1. Work out molecular formulae from these structures2. Identify similarities and differences

Aspirin

Why do we use Aspirin?

1. reduces pain2. lowers body temperature rapidly 3. makes the blood thinner to reduce risks of blood clots

Advantages of soluble Aspirin:

It gets into the blood stream faster ( see next page for explanation)

Disadvantages (HIGHER only):People who have stomach ulcers find that aspirin aggravates the ulcer and causes stomach belleding

Side-effects also include headaches, dizziness and ringing in the ears.

Children and teenagers may get Reye’s Syndrome which affects the liver and brain

What are the dangers of taking an overdoses of Aspirin or Paracetamol?

Aspirin and paracetamol are safe if you follow the dosage on the box

1. Lower blood pressure2. Increased heart rate3.Breathing problems4. Vomiting5. Internal bleedingHigherDescribe and explain differences in solubility between Aspirin and soluble Aspirin in terms of structure and effect.

Aspirin can be fatal but if caught in time there is a good chance of recovery

Paracetamol is much more serious as it leads to irreversible liver damage

Aspirin is not very soluble so it gets to the affected part of the body very slowly.

The reaction above shows how soluble Aspirin is made. Note that the normally covalently bonded molecule now has an ionic group (charged particles)

Water has slight positive and negative charges so the soluble Aspirin is attracted to the water molecule due to the charges. This makes it more soluble than ordinary Aspirin.

How is Aspirin Made?

Aspirin was first discovered in willow bark.

Aspirin is now manufactured synthetically in industry (man-made).

Higher

Describe how aspirin is manufactured from salicylic acid.

Salicylic acid + ethanoic anhydride aspirin + ethanoic acid

Method1. Mix salicylic acid with ethanoic anhydride.

2. Add a few drops of concentrated sulphuric acid

3. Heat the mixture to 500C for a few minutes

4. Filter off the precipitate (the solid that has formed)

Acid Catalyst

You don’t need to learn this symbol equation !!