• Accelerated hypertension
• Sodium nitroprusside is a very potent agent
• use only on the advice of a renal SpR/consultant
• use only on wards (e.g. critical care unit/CCU) where continuous monitoring of BP (preferably via arterial line) is possible

• Compensatory hypertension
• Impaired cerebral circulation
• Leber’s optic atrophy
• Severe B₁₂ deficiency

• Sodium nitroprusside 50 mg ampoules/vials for reconstitution

• Glucose 5%

• Administer sodium nitroprusside either in a 50 mL syringe via a syringe pump, or in 500 mL bags using a controlled infusion device for precise control of flow rate
• choice of bag size or use of syringe pump depend on dosage, patient weight and fluid status and availability of equipment
• Take care to avoid extravasation. Check infusion site regularly

How to start and adjust doses

• Initially 0.3 microgram/kg/min by IV infusion
• increase to 0.5 microgram/kg/min
• then in increments of 0.5 microgram/kg/min according to response allowing 5-10 min between each increment
• Maximum dose = 8 microgram/kg/min

Infusion via syringe pump

• Reconstitute sodium nitroprusside with 2 mL of glucose 5%
• Withdraw resulting solution and make up to 50 mL with glucose 5% (50 mg in 50 mL = 1 mg/mL)
• mix thoroughly
• Infusion solution has a faint orange-brownish tint. If it is highly coloured do not use
• Sodium nitroprusside must be protected from light
• immediately wrap syringe and tubing with foil provided
• infusion solution is then stable for up to 24 hr from time of preparation

Table 1: Administration of sodium nitroprusside (1 mg/mL) via syringe pump (rate mL/hr)
Concentration = 50 mg in 50 mL = 1000 microgram/mL (1 mg/mL). If weight <45 kg or >100 kg, discuss with renal team

Dosage (microgram/ kg/min)	Weight (kg)
	45	50	55	60	65	70	75	80	85	90	95	100
0.3	0.8	0.9	1.0	1.1	1.2	1.3	1.4	1.4	1.5	1.6	1.7	1.8
0.5	1.4	1.5	1.7	1.8	2.0	2.1	2.3	2.4	2.6	2.7	2.9	3.0
1.0	2.7	3.0	3.3	3.6	3.9	4.2	4.5	4.8	5.1	5.4	5.7	6.0
1.5	4.1	4.5	5.0	5.4	5.9	6.3	6.8	7.2	7.7	8.1	8.6	9.0
2.0	5.4	6.0	6.6	7.2	7.8	8.4	9.0	9.6	10.2	10.8	11.4	12.0
2.5	6.8	7.5	8.3	9.0	9.8	10.5	11.3	12.0	12.8	13.5	14.3	15.0
3.0	8.1	9.0	9.9	10.8	11.7	12.6	13.5	14.4	15.3	16.2	17.1	18.0
3.5	9.5	10.5	11.6	12.6	13.7	14.7	15.8	16.8	17.9	18.9	20.0	21.0
4.0	10.8	12.0	13.2	14.4	15.6	16.8	18.0	19.2	20.4	21.6	22.8	24.0
4.5	12.2	13.5	14.9	16.2	17.6	18.9	20.3	21.6	23.0	24.3	25.7	27.0
5.0	13.5	15.0	16.5	18.0	19.5	21.0	22.5	24.0	25.5	27.0	28.5	30.0
5.5	14.9	16.5	18.2	19.8	21.5	23.1	24.8	26.4	28.1	29.7	31.4	33.0
6.0	16.2	18.0	19.8	21.6	23.4	25.2	27.0	28.8	30.6	32.4	34.2	36.0
6.5	17.6	19.5	21.5	23.4	25.4	27.3	29.3	31.2	33.2	35.1	37.1	39.0
7.0	18.9	21.0	23.1	25.2	27.3	29.4	31.5	33.6	35.7	37.8	39.9	42.0
7.5	20.3	22.5	24.8	27.0	29.3	31.5	33.8	36.0	38.3	40.5	42.8	45.0
8.0	21.6	24.0	26.4	28.8	31.2	33.6	36.0	38.4	40.8	43.2	45.6	48.0

Infusion in a bag via a controlled-infusion device

Table 2: Administration of sodium nitroprusside (100 microgram/mL) via infusion bag (rate mL/hr). Concentration = 50 mg in 500 mL = 100 microgram/mL

Dosage (microgram/kg/min)	Weight (kg)
	45	50	55	60	65	70	75	80	85	90	95	100
0.3	8	9	10	11	12	13	14	14	15	16	17	18
0.5	14	15	17	18	20	21	23	24	26	27	29	30
1.0	27	30	33	36	39	42	45	48	51	54	57	60
1.5	41	45	50	54	59	63	68	72	77	81	86	90
2.0	54	60	66	72	78	84	90	96	102	108	114	120
2.5	68	75	83	90	98	105	113	120	128	135	143	150
3.0	81	90	99	108	117	126	135	144	153	162	171	180
3.5	95	105	116	126	137	147	158	168	179	189	200	210
4.0	108	120	132	144	156	168	180	192	204	216	228	240
4.5	122	135	149	162	176	189	203	216	230	243	257	270
5.0	135	150	165	180	195	210	225	240	255	270	285	300
5.5	149	165	182	198	215	232	248	264	281	297	314	330
6.0	162	180	198	216	234	252	270	288	306	324	342	360
6.5	176	195	215	234	254	273	293	312	332	351	371	390
7.0	189	210	231	252	273	294	315	336	357	378	399	420
7.5	203	225	248	270	293	315	338	360	383	405	428	450
8.0	216	240	264	288	312	336	360	384	408	432	456	480

• Reconstitute sodium nitroprusside with 2 mL of glucose 5%
• Withdraw resulting solution and add to 500 mL bag of 5% glucose that has had 2 mL of diluent removed
  • mix thoroughly
• Infusion solution has a faint orange-brownish tint. If it is highly coloured, do not use
• Sodium nitroprusside must be protected from light
  • immediately wrap infusion bag and all parts of administration set with foil provided
  • infusion solution is then stable for up to 24 hr from time of preparation
• Flow rate corresponding to required dosage and patient's weight in shaded area of Table 2, a more concentrated solution may be more appropriate/practical - see Table 3

Table 3: Administration of sodium nitroprusside (200 microgram/mL) via infusion bag (rate mL/hr). Concentration = 50 mg in 250 mL = 200 microgram/mL

Dosage (microgram/kg/min)	Weight (kg)
	45	50	55	60	65	70	75	80	85	90	95	100
0.3	4	5	5	5	6	6	7	7	8	8	9	9
0.5	7	8	8	9	10	11	11	12	13	14	14	15
1.0	14	15	17	18	20	21	23	24	26	27	29	30
1.5	20	23	25	27	29	32	34	36	38	41	43	45
2.0	27	30	33	36	39	42	45	48	51	54	57	60
2.5	34	38	41	45	49	53	56	60	64	68	71	75
3.0	41	45	50	54	59	63	68	72	77	81	86	90
3.5	47	53	58	63	68	74	79	84	89	95	100	105
4.0	54	60	66	72	78	84	90	96	102	108	114	120
4.5	61	68	74	81	88	95	101	108	115	122	128	135
5.0	68	75	83	90	98	105	113	120	128	135	143	150
5.5	74	83	91	99	107	116	124	132	140	149	157	165
6.0	81	90	99	108	117	126	135	144	153	162	171	180
6.5	88	98	107	117	127	137	146	156	166	176	185	195
7.0	95	105	116	126	137	147	158	168	179	189	200	210
7.5	101	113	124	135	146	158	169	180	191	203	214	225
8.0	108	120	132	144	156	168	180	192	204	216	228	240

• Reconstitute sodium nitroprusside with 2 mL of glucose 5%
• Withdraw resulting solution and add to 250 mL bag of 5% glucose that has had 2 mL of diluent removed
  
  • mix thoroughly
• Infusion solution has a faint orange-brownish tint. If it is highly coloured, do not use
• Sodium nitroprusside must be protected from light
  • immediately wrap infusion bag and all parts of administration set with foil provided
  • infusion solution is then stable for up to 24 hr from time of preparation
• Flow rate corresponding to required dosage and patient's weight in shaded area of Table 3, infusion via syringe pump may be more appropriate/practical - see Table 1

• Aim to reduce diastolic BP to 110-115 mmHg over several hours
• Patients already taking antihypertensive drugs and the elderly will be more sensitive to sodium nitroprusside
• If BP not adequately reduced within 10 min at maximum dosage, discontinue infusion - see Accelerated hypertension guideline for alternative

Monitoring

• Monitor BP and symptoms carefully
• Over-rapid reduction in BP may produce the following symptoms:
• headache, dizziness, perspiration
• nausea, retching, abdominal pain
• palpitations, apprehension, retrosternal discomfort
• If these occur, reduce infusion rate in decrements of 0.5 microgram/kg/min

Length of treatment

• Sodium nitroprusside is metabolised to free cyanide, converted in the liver to thiocyanate
• if response obtained, continue therapy only for a few hours to avoid risk of toxicity
• If therapy required for >24 hr, consult manufacturer's literature on monitoring and management of potential toxicity, normally maximum is 3 days
• signs of toxicity include tachycardia, sweating, hyperventilation, arrhythmias, marked metabolic acidosis

Withdrawal

• Start oral antihypertensive therapy while BP is being controlled by sodium nitroprusside
• When finally withdrawing sodium nitroprusside, to prevent rebound increase in BP, reduce infusion rate gradually terminating over 15-30 min
• reduce by 25-30% every 5 min, rechecking BP before each decrement