Drugs Igcse

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DRUGS

A drug is a chemical substance taken into the body that modifies or affects chemical reactions in the body.

Generally, drugs are developed for medical use.

Without drugs, people would live much shorter lives or suffer greater pain.

All drugs are dangerous when misused.

ANTIBIOTICS

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What are Antibiotics?

a chemical substance , produced by a microorganism (bacterium or fungus) which will inhibit the growth or replication of other microorganisms.

• Effective antibiotics show selective toxicity – killing or disabling pathogens without harming host cells.

• Wide range to treat fungal and bacterial infections.

• Antibiotics are not effective against viruses.

MECHANISMS OF ANTIBIOTIC ACTION

• interfere with making of bacterial cell walls:

eg., penicillin

Weaken bacterial cell walls. Walls made of

chains of peptidoglycan molecules. Penicillin

prevents linking of peptidoglycan molecules.

Cell wall becomes weak, bacterium bursts

(lysis).

• Do not act on viruses.

No form of cellular structure- no cell walls

or cell organelles.

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PRESCRIPTION OF AN antibiotic

• Usually a doctor faced with a patient who needs immediate treatment makes an educated guess at what is causing the infection and what antibiotic is needed so that treatment can start right away.

• Necessary to test which antibiotics the microorganism is sensitive to.

• Place discs soaked in different antibiotics onto agar jelly on which the bacterium is growing.

• If a clear area of a certain diameter appears around the disc the antibiotic is effective.

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Antibiotic Resistant Bacteria Are:

Bacteria mutate and are able to resist the antibiotics that are meant to kill them.

This is a normal process speeded up by the overuse and misuse of antibiotics.

THE MORE WE USE ANTIBIOTICS THE MORE SELECTION PRESSURE WE PUT ON BACTERIA TO EVOLVE RESISTANCE.

HEROIN

• Opium poppies produce opium

▪ Opium has many chemicals.

▪ Some of these, morphine and codeine are used in medicine for relief of pain.

▪ Heroin also got from opium

• Also used in medicine

Is addictive

Addictive drug

• One which causes a person to become dependent on it

• Not able to stop taking the drug without suffering severe psychological and physical symptoms

Risks of heroin

• Heroin is

▪ A powerful depressant

• Slows down impulses along neurones transferring information from pain receptors to brain

• Reduces pain

• Slows down breathing

▪ Produces feelings of euphoria

• Intensely happy

▪ highly addictive and tolerance to the drug builds up rapidly

• This means more and more of the drug is needed to create the same high.

HEROIN – ABUSE

← become dependent on them.

← need larger amounts to feel satisfied.

← Lose ability to be part of normal society.

← Not be able hold on to a job

← no longer in control of lives.

← commit crime to get money.

← make families and friends sad.

← Those who inject heroin

← face the risk of hepatitis and

← HIV infection from the use of dirty needles

← Pregnant women who use heroin

← risk giving birth to smaller babies

← who are also addicted to heroin.

← The baby will experience withdrawal symptoms soon after birth.

Battle against heroin

• Withdrawal symptoms are unpleasant and even life-threatening.

• Sleeplessness, hallucinations, muscle cramps, sweating, vomiting and nausea

• Symptoms called cold turkey

• Can be won

• Going into rehabilitation – staying in a treatment centre

• With will power

• Help from others...
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