Ratio Strengths

1 in X means…

1 gram of a substance in X millilitres of liquid

The larger the number the weaker/stronger the concentration?

Weaker

Q. A 26 year old requires 0.5mL of a 1 in 1000 intramuscular injection of adrenaline for the treatment of anaphylaxis.

How many micrograms of adrenaline would the patient receive?

500 mcg

Q. You are working as a pharmacist in a pediatric clinic. A father brings in his 5-year-old son who is experiencing a severe allergic reaction.

You administer a 0.3 mL dose of adrenaline 1 in 1000 w/v solution by intramuscular injection.

How many micrograms of adrenaline are contained in the 0.3 mL dose?

300 mcg

Q. A 7-year-old child is in cardiac arrest, and the medical team decides to administer adrenaline as part of cardiopulmonary resuscitation (CPR).

You prepare a 5 mL dose of adrenaline 1 in 10,000 w/v solution, which is to be given by intravenous injection.

How many micrograms of adrenaline are contained in the 5 mL dose?

500 mcg

Q. A nurse takes a 5mL ampoule containing 1 in 200 w/v of lidocaine to administer to a neonate for the treatment of ventricular fibrillation. The nurse must administer a dose of 5mg of lidocaine to the patient.

How many millilitres of the lidocaine solution in the ampoule will contain the dose for the patient?

1 mL