Hi Robin,
A 'loading dose' is much higher than a normal daily maintenance dose. It is usually given over a shorter period to
quickly increase the level of drug circulating in the blood system, thus bringing about a quicker effect on the body and
reducing whatever problem it's meant to be aimed at.
The length of time it's given is usually governed by the prescribing physician and the previous trials done on the drug,
however there are some rules 'laid down' which are normally considered.
Hope this helps.
Gogs