| Date | May 2018 | Marks available | 2 | Reference code | 18M.3.sl.TZ2.15 |
| Level | SL | Paper | 3 | Time zone | TZ2 |
| Command term | Distinguish | Question number | 15 | Adapted from | N/A |
Question
Drug testing is necessary to determine safe and effective doses.
Distinguish between the lethal dose (LD50) and the toxic dose (TD50).
Markscheme
LD50: amount/dose that kills 50% of the population
TD50: amount/dose that negatively affects/produces toxic effects in 50% of the population
Award [1 max] for “LD50 used in animal trials AND TD50 used in human studies”.
[2 marks]
Examiners report
Syllabus sections
- 17N.3.sl.TZ0.18b: State the method of drug administration that gives the maximum bioavailability.
-
17M.3.sl.TZ2.15b.ii:
Compare, giving a reason, the bioavailability of soluble aspirin with aspirin.
-
20N.3.sl.TZ0.12:
Consider the following antacids:
Show that antacid X is more effective, per tablet, than antacid Y.
- 18N.3.sl.TZ0.12a: State the internal bond angles in the β-lactam ring and the expected bond angles for the same...
- 18N.3.sl.TZ0.13c: Outline the meaning of the bioavailability of a drug.
- 18N.3.hl.TZ0.17b: Outline the meaning of the bioavailability of a drug.
-
19M.3.hl.TZ1.22b:
Suggest a reason for using a phosphate salt of oseltamivir in oral tablets.
-
19M.3.sl.TZ1.17a(ii):
Suggest a reason for using a phosphate salt of oseltamivir in oral tablets.
-
17M.3.sl.TZ2.18b:
Suggest one ethical consideration faced by medical researchers when developing medications.
- 19N.3.hl.TZ0.21b: Experimental research on both animals and humans contributes to the development...
-
18M.3.sl.TZ1.13b.i:
State what is meant by the bioavailability of a drug.
-
19M.3.hl.TZ2.21a:
Distinguish between therapeutic window and therapeutic index in humans.
Therapeutic window:
Therapeutic index:
-
17N.3.sl.TZ0.18a:
Outline the difference between the therapeutic index in animal studies and the therapeutic index in humans.
-
17M.3.sl.TZ1.18a:
Dose response curves are determined for each drug.
Outline the significance of range “a”.
-
19M.3.sl.TZ2.14a:
Distinguish between therapeutic window and therapeutic index in humans.
Therapeutic window:
Therapeutic index:
-
20N.3.sl.TZ0.11d:
Comment on the risk of overdose when taking aspirin as an analgesic, referring to the following values, for a person weighing :
Minimum therapeutic dose
Estimated minimum lethal dose
-
20N.3.hl.TZ0.15d:
Comment on the risk of overdose when taking aspirin as an analgesic, referring to the following values, for a person weighing :
Minimum therapeutic dose
Estimated minimum lethal dose
