PCP 9 - dosage calculations and quantity to supply p1

What is a dose?

• a dose is the quantity or amount of drug administered to a patient to achieve a therapeutic outcome

What is a dosage regime?

The scheduling of doses is known as the dosage regime

What is a pharmaceutical month ?

• 28 days

What are variable dosage amounts ?

• when the number of tablets vary - eg 1 or 2 etc

How to workout the number of tablets needed ?

-Calculate the min no of tablets

-Calculate the max no of tablets

-then provide between these 2 numbers

-take into consideration what the patient says

What are some notations ?

OD- every day

BD- twice a day

TDS- three times a day

QDS- 4 times a day

3/7 = for 3 days

4/52= for 4 weeks

6/12 = for 6 months

What is the normal unit of measurement for oral liquid medicines ?

• 5ml spoons or multiples

• if dose is less than 5 ml —- use a syringe

working out drops

- see how many drops are per unit

What do you do when you have medications in special containers ?

• can’t split

• would need to supply multiple

• to look at whether we round up or down look at nhs drug tariff

How do you workout the doses /amount for creams ?

• BNF provides estimate for twice daily application for one week to following body areas

Example - calculation based on weight of drug ?

A prescription requires a patient to receive 20 mg of a
drug (in tablet form) every 8 hours for 4 weeks. How
many tablets are required?
(The drug is available as 10 mg tablets)

step 1 - calculate the dose per day

Dosage per day = 20 × (24 ÷ 8) = 60 mg per day

step 2 - the dose for how many days/the total dose

How many days? = 4 × 7 = 28 days
Total dose needed = 60 × 28 = 1680 mg

step 3- then divide by weight of tablets

Available in 10 mg tablets, therefore you will need:
1680 ÷ 10 = 168 tablets