Option D: Medicines and Drugs Flashcards
Pharmaceutical products
List the effects of medicines and drugs on the functioning of the body.
Generally, a medicine or drug is any chemical (natural or manmade) that does one or more of the following.
- alters incoming sensory sensations
- alters mood or emotions
- alters physiological state (including consciousness, activity level, or coordination)
The importance of the body’s natural healing processes and the placebo effect should be stressed.
Pharmaceutical products
Outline the stages involved in the research, development and testing of new pharmaceutical products.
Research & development = long & expensive process.
Traditionally, new product is isolated from existing species/synthesized chemically then subjected to thorough laboratory + clinical pharmacological studies to demonstrate its effectiveness.
- Animal Testing / Therapeutic Index
- Before studies on humans, product tested on animals to determine lethal dose required to kill 50% of animal pop. (LD50)
- effective dose required to bring about noticeable effect in 50% of animal pop. also obtained (ED50)
-
therapeutic index / therapeutic window calculated
- Therapeutic index = LD50/ED50
- e.g. index of 100, then LD50/ED50 = 100:1; means hundredfold increase in dose corresponding to ED50 results in 50% death rate
- Initial clinical trial on humans
- usually on volunteers & patients (1/2 given placebo)
- initial trial closely monitored to establish drug’s safety & possible side effects
- Placebo effect: body’s natural healing process due to individual expectation
- used in double blind trials in drug development / (pharmacologically) inert substance used as a control / placebo given to some patients in a drug trial so that effects on other patients who have been given the real drug can be compared
- Looking for side effects
- drugs usually have unwanted side effects
- e.g. aspirin = bleeding of stomach
- morphine = constipation
- side effects are relative (heart attack patients use aspirin as anti-clotting agent; morphine + kaolin mixture for diarrhea)
- severity of complaint determines risk-to-benefit ratio (effective treatment for life-threatening disease, higher risk from side effects acceptable)
- drugs usually have unwanted side effects
- Tolerance of drugs
- tolerance as body adapts to drug
- increasing amounts of doses for original effect
- danger: as dose increases, so does risk of dependence & reaching lethal dose
- Further tests
- use is gradually widened in a variety of clinical situations
- Approval
- by drug administration of particular country
- over-the-counter drug or by prescription
Pharmaceutical products
Describe the different methods of administering drugs.
most drugs → bloodstream
- oral
- inhalation
- rectal (through anus)
-
parenteral (injection)
- intramuscular (arms, legs, buttocks)
- intravenous (most rapid effect; directly into bloodstream)
- subcutaneous (directly under skin)
- topically (limit effect to site of disorder) → e.g. creams, ointments, sprays, drops
Pharmaceutical products
Discuss the terms therapeutic window, tolerance and side-effects.
Therapeutic window: aka therapeutic index; relates therapeutic effects of drug to toxic effects. Window of 100 = LD50/ED50 = 100:1 = 100X dose corresponding to ED50 is 50% death rate.
Tolerance: tolerance for drug as body adapts to action of drug. ↑ tolerance = ↑ dose for same effect = increased danger of dependence/reaching lethal dose
Side effects: unwanted effects of drugs, risk-to-benefit ratio determines acceptability of side effect risks. E.g. Thalidomide for morning sickness pregnant women (sold w/o prescription, marketed as safe, very profitable → side effects = children with malformed/absent limbs)
Antacids
State and explain how excess acidity in the stomach can be reduced by the use of different bases.
- stomach walls lined with:
- layer of cells which secrete mucus
- protects stomach wall from acid
- pepsinogen (precursor for pepsin)
- HCl (gastric juices)
- layer of cells which secrete mucus
- [H+] of HCl b/w 1.5 & 2.5 pH
- excess acid = eating away at mucus lining = indigestion
- indigestion from overeating, stress, smoking, alcohol, certain types of food; some drugs e.g. aspirin could irritate & cause ulceration of stomach walls by gastric acid
-
antacids combat indigestion
- 1-3 hours after eating
-
bases: metal oxides, carbonates, hydrogen carbonates, hydroxides
- e.g. NaHCO3, CaCO3, Al(OH)3, milk of magnesia
- neutralize acid, prevent inflammation, relieve pain and discomfort, allow stomach lining mucus to mend
- ulcers: prevent acid from attacking damaged stomach lining → allow ulcer to heal
Analgesics
Describe and explain the different ways that analgesics prevent pain.
Analgesics
Describe the use of derivatives of salicylic acid as mild analgesics, and compare the advantages and disadvantages of using aspirin and paracetamol (acetaminophen).
Analgesics
Compare the structures of morphine, codeine and diamorphine (heroin, a semi-synthetic opiate).
Analgesics
Discuss the advantages and disadvantages of using morphine and its derivatives as strong analgesics.
Depressants
Describe the effects of depressants.
Depressants
Discuss the social and physiological effects of the use and abuse of ethanol.
Depressants
Describe and explain the techniques used for the detection of ethanol in the breath, the blood and urine.
Depressants
Describe the synergistic effects of ethanol with other drugs.
Depressants
Identify other commonly used depressants and describe their structures.
Stimulants
List the physiological effects of stimulants.
Stimulants
Compare amphetamines and epinephrine (adrenaline).
Stimulants
Discuss the short- and long-term effects of nicotine consumption.
Stimulants
Describe the effects of caffeine and compare its structure with that of nicotine.
Antibacterials
Outline the historical development of penicillins.
Antibacterials
Explain how penicillins work and discuss the effects of modifying the side-chain.
Antibacterials
Discuss and explain the importance of patient compliance and the effect of penicillin overprescription.
Antivirals
State how viruses differ from bacteria.
Antivirals
Describe the different ways in which antiviral drugs work.
Antivirals
Discuss the difficulties associated with solving the AIDS problem.
