PILLS - Using ratios

Using ratios

Some drugs are expressed as ratios. This is still straightforward and can be easily worked out. Adrenaline is a drug commonly expressed in this way.

Table: Drug strength and quantity in solution

Strength as a ratio	Weight in volume	Weight per ml
1:1,000,000	1g in 1,000,000ml	1 microgram in 1ml
1:100,000	1g in 100,000ml	10 micrograms in 1ml
1:10,000	1g in 10,000ml	100 micrograms in 1ml
1:1000	1g in 1000ml	1mg in 1ml
1:100	1g in 100ml	10mg in 1ml
1:10	1g in 10ml	100mg in 1ml

Therefore:

1:1000 adrenaline contains:
1g in 1000ml = 1000mg in 1000ml = 1mg in 1ml

1:10,000 adrenaline contains:

1g in 10,000ml = 1000mg in 10,000ml = 1mg in 10ml = 100microgram in 1ml

Have a look at your student formulary at the Emergency Drugs section - you will start covering these in year 2 when you cover how to manage emergencies

TIP: If ever in doubt when it comes to drug calculations, always ask!