Emirates International School
Grade 13
Medicines and drugs “Analgesics”
Name:………………………………………………….
1.
.
a.
2.
3.
Date:………………………………………
Define
the
terms
analgesic,
mild
analgesic
and
strong
analgesic.
Analgesics are drugs that relieve pain (without causing loss of consciousness). Mild analgesics used for relief
of mild pain (and frequently fever). Strong analgesics used for the relief of very severe pain include the
narcotics morphine, heroin (also called diacetylmorphine or diamorphine) and codeine.
b. Explain the difference in mode of action of a mild analgesic compared to a strong analgesic.
Mild analgesics function by intercepting the pain stimulus at the source, for example by interfering with the
production of substances (such as prostaglandins) that cause pain, swelling or fever. Strong analgesics work
by temporarily bonding to receptor sites in the brain, preventing the transmission of pain impulses without
depressing the central nervous system.
c. Give
two
examples
of
each
of
a
mild
and
a
strong
analgesic.
Examples of mild analgesics: aspirin, acetaminophen Examples of strong analgesics include the narcotics
morphine, heroin (and codeine).
From the structures in the Data Booklet:
a. Identify
two
functional
groups
present
in
the
structure
of
aspirin.
benzoic acid/carboxylic acid and the ester group (Ar-COOCH3)
b. Name
the
nitrogen
containing
functional
group
in
acetaminophen.
Amide group (-NHCO-)
c. Name
the
nitrogen
containing
functional
group
in
codeine.
Tertiary amine/amine
d. Suggest
how
heroin
can
be
chemically
prepared
from
morphine.
Replace the two –OH groups on morphine by two ester (CH3COO-) groups
.
a. Besides the use of aspirin as an analgesic, list three other uses of the drug.
As an antipyretic to reduce fever, as an anti-inflammatory agent when there is swelling from injuries and as
an anti-platelet agent in the prevention of abnormal blood clotting and as an anti clotting agent after heart
surgery.
b. State
three
disadvantages
of
using
aspirin.
Aspirin can cause stomach upset and internal bleeding (due to its acidic nature in aqueous solution,); it can
cause ulceration and aggravate existing peptic ulcers. Allergic reaction leading to skin rashes, respiratory
difficulty, and even shock, development of Reye’s syndrome in children (a potentially fatal liver and brain
disorder).
c. Discuss the advantages and disadvantages of using morphine and its derivatives as strong analgesics.
In the relief of severe pain caused by injury, chronic disease such as cancer, prior to and recovery from
surgery; in the treatment of diarrhoea by producing a constipating effect; to relieve coughing by suppressing
the ‘cough centre’ situated in the brain stem. Disadvantages: Opiates produce drowsiness, mood changes and
mental clouding (psychological effects). Users develop tolerance to the drug (need more for the same effect),
as well as physical dependence, a state in which users do not function properly without a drug. Withdrawal is
experienced when the drug is not regularly administered; symptoms include restlessness, sweating, fever,
chills, vomiting, increased rate of respiration, cramping, diarrhoea, unbearable aches and pains..