Introduction - Uppsala Monitoring Centre

a low toxic-therapeutic ratio or a low therapeutic index, e.g. digoxin. These are the
drugs one would expect to have problems when the amount of the active principle is
unknown. These drugs will have ADR, which should be picked up more easily due
to their frequency. As mentioned earlier mercury dosage was increased until
salivation occurred. Withering also increased the dose of digitalis until the patient
vomited in the belief that this would ensure a diuretic effect. Quinine dosage was
increased until there was singing in the ears. The principle of increasing the dosage
until an adverse reaction occurred must have been common with drugs/herbs with a
low therapeutic index. In the beginning the amount of herbs to be taken must have
been measured numerically for berries and leaves, but roots and stems would have
been more difficult.
Thompson says that the symbols were first employed by the Chaldeans
(mathematicians or astrologers from Babylonia) and Babylonians, but that
Alexander was the first to use the scruple and dragma. Before the 13 th century
they used ‘a piece the size of a corn’ and ‘a pinch’ (Thompson, 2003). In the
Leechbook of 1443 a dose of a ‘spoonful’ is mentioned and De Vigo in 1506 refers
to a ‘groat’s weight. By 1527 a ‘dram’ and a ‘scruple’ were used in a prescription
(Banister, 1589). Pope in 1553 said, ‘The least of all weights (commonly used by
physicians) is a barley corne, and xx (20) cornes make a scruple, three scruples
make one drachme and eight drachms make one ounce’.
A corne = gra = G = a grayne = a grain
A scruple = ℈ = scrupulus
A drachme = ʒ = dragma = dram
An unce = ℥ = unciam = ounce
A pounde = l = libra
A quarter = q
A half = s = ss = β
A handfull = m
One = j (Pope, 1553).
However, in 1579 Thomas Cartwright was using handfuls of elder leaves, one
spoonful of turpentine and also uses the phrase ‘by as even portions as you can
guess’. Those prescriptions for medicines for external use often did not specify
quantities, e.g. ‘then take bramble leaves, elder leaves, mustard seeds, and stamp
them all together.’ (Cartwright, 1579).
The amount of a drug in an ointment or in other preparations for external use
could be less accurate in dose without causing serious harm, but for those drugs
taken orally the possible variation in dose, when added to the inconstancy of the
amount of active principle due to the difference mentioned above, might be fatal.