Journal of Prescribing Practice - Tinzaparin treatment dose in adults

Tinzaparin is presented in syringes and vials containing 20 000 units/mL. The dosage of tinzaparin for treatment of venous thromboembolism is 175 units/kg bodyweight once daily. The dose should be rounded up or down to the nearest 0.05 mL dose volume. Tinzaparin is administered by subcutaneous injection. A dosing chart should always be used when calculating doses of tinzaparin. For these examples, try calculating the dose using your maths skills, then use the dosing chart below to check your answers.

QUESTION 1

Mr A. Weight: 75 kg

QUESTION 2

Mrs B. Weight: 59 kg

QUESTION 3

Mr C. Weight: 93 kg

QUESTION 4

Mrs D. Weight: 121 kg

Table 1. Tinzaparin treatment dose in adults (East Lancashire Health Economy, 2024)

SyringeMarking/volume	BodyweightKg	Stones/lbs	Prescribed doseAnti-factor XA units	Injection volumemL
ORANGE	0.4 mL	35	5/7	6 000 units	0.3 mL
ORANGE	0.4 mL	40	6/4	7 000 units	0.35 mL
ORANGE	0.4 mL	45	7/1	8 000 units	0.4 mL
RED	0.5 mL	50	7/12	9 000 units	0.45 mL
RED	0.5 mL	55	8/9	10 000 units	0.5 mL
BROWN	0.6 mL	60	9/6	11 000 units	0.55 mL
BROWN	0.6 mL	65	10/3	11 000 units	0.55 mL
BROWN	0.5 mL	70	11/10	12 000 units	0.6 mL
YELLOW	0.7 mL	75	11/11	13 000 units	0.65 mL
YELLOW	0.7 mL	80	12/8	14 000 units	0.7 mL
GREEN	0.8 mL	85	13/5	15 000 units	0.75 mL
GREEN	0.8 mL	90	14/2	16 000 units	0.8 mL
BLUE	0.9 mL	95	14/13	17 000 units	0.85 mL
BLUE	0.9 mL	100	15/10	18 000 units	0.9 mL
BLUE	0.9 mL	105	16/7	18 000 units	0.9 mL
Multi-dose via		110	17/5	19 000 units	0.95 mL
Multi-dose via		115	18/2	20 000 units	1 mL
40000 units in 2 mL		120	18/13	21 000 units	1.05 mL
		125	19/10	22 000 units	1.10 mL
		130	20/7	23 000 units	1.15 mL
		135	21/4	24 000 units	1.2 mL
		140	22/1	25 000 units	1.25 mL