page130
Breast-feeding
manufacturer advises avoid—present
in milk in
animal
studies
Side-effects
gastro-intestinal disturbances; peripheral
oedema,
flushing;
headache,
insomnia, fatigue,
dizzi-
ness; decreased haemoglobin, prolonged prothrombin
time, increased INR; muscle cramp; nasal congestion,
epistaxis
Dose
.
ADULT
over 18 years 100 mg once daily
Thelin
c
(Encysive) T A
Tablets
,
f/c,
yellow-orange,
sitaxentan sodium
100 mg,
net price 28-tab pack = £1540.00
Note
All
orders of
Thelin should be based on a prescription
from a specialist in Pulmonary Arterial Hypertension, who has
received appropriate training as part of the Programmed
Access to Sitaxentan Sodium (PASS) scheme. Orders should be
placed with Polarspeed at 01525 217211
SODIUM NITROPRUSSIDE
Indications
hypertensive emergencies (see section
2.5);
controlled hypotension in anaesthesia; acute or
chronic heart failure
Cautions
hypothyroidism, hyponatraemia,
ischaemic
heart disease,
impaired cerebral circulation,
elderly;
hypothermia; monitor blood pressure and blood-cya-
nide concentration and if treatment exceeds 3 days,
also blood-thiocyanate concentration;
avoid sudden
withdrawal—terminate infusion over 15–30 minutes;
protect infusion from light;
interactions: Appendix 1
(sodium nitroprusside)
Contra-indications
severe vitamin B
12
deficiency;
Leber’s optic atrophy;
compensatory hypertension
Hepatic impairment
use with caution; avoid in
hepatic failure—cyanide or thiocyanate metabolites
may accumulate
Renal impairment
avoid prolonged use—cyanide or
thiocyanate metabolites may accumulate
Pregnancy
avoid prolonged use—potential for accu-
mulation of cyanide in fetus
Breast-feeding
no information available;
caution
advised due to thiocyanate metabolite
Side-effects
associated with over rapid reduction in
blood pressure (reduce infusion rate): headache,
diz-
ziness, nausea, retching, abdominal pain, perspiration,
palpitation,
anxiety,
retrosternal discomfort;
occa-
sionally reduced platelet count,
acute transient phle-
bitis
Cyanide
Side-effects caused by excessive plasma concen-
tration of the cyanide metabolite include tachycardia,
sweating, hyperventilation, arrhythmias, marked metabolic
acidosis (discontinue and give antidote, see p.
39)
Dose
. Hypertensive emergencies,
by intravenous infusion,
initially 0.5–1.5 micrograms/kg/minute,
then
increased in steps of 500 nanograms/kg/minute
every 5 minutes within range 0.5–8 micrograms/kg/
minute (lower doses if already receiving other anti-
hypertensives);
stop if response unsatisfactory with
max.
dose in 10 minutes
Note
Lower initial
dose of
300 nanograms/kg/minute has
been used
. Maintenance of blood pressure at 30–40% lower than
pretreatment diastolic blood pressure,
20–400 micr-
ograms/minute (lower doses for patients being trea-
ted with other antihypertensives)
. Controlled hypotension in surgery,
by intravenous
infusion,
max.
1.5 micrograms/kg/minute
. Heart failure,
by intravenous infusion,
initially 10–
15 micrograms/minute,
increased every 5–10 min-
utes as necessary;
usual range 10–200 micrograms/
minute normally for max.
3 days
Sodium Nitroprusside
(Non-proprietary) A
Intravenous infusion
,
powder for reconstitution,
sodium nitroprusside 10 mg/mL
Available from ‘special-order’
manufacturers or spe-
cialist importing companies,
see p.
988
TADALAFIL
Indications
pulmonary arterial hypertension;
erectile
dysfunction (section 7.4.5)
Cautions
hypotension (avoid if systolic blood pressure
below 90 mmHg);
aortic and mitral valve disease;
pericardial constriction; congestive cardiomyopathy;
left ventricular dysfunction;
life-threatening arrhyth-
mias;
coronary artery disease; uncontrolled hyper-
tension;
pulmonary veno-occlusive disease;
predis-
position to priapism;
anatomical deformation of the
penis;
hereditary degenerative retinal disorders;
interactions: Appendix 1 (tadalafil)
Contra-indications
acute myocardial infarction in
past 90 days; history of non-arteritic anterior
ischaemic optic neuropathy; avoid concomitant use of
nitrates
Hepatic impairment
initially 20 mg once daily in mild
to moderate impairment; avoid in severe impairment
Renal impairment
initially 20 mg once daily in mild to
moderate impairment, increased to 40 mg once daily
if tolerated;
avoid in severe impairment
Pregnancy
manufacturer advises avoid
Breast-feeding
manufacturer advises avoid—present
in milk in
animal
studies
Side-effects
nausea,
vomiting,
dyspepsia,
gastro-
oesophageal reflux,
chest pain,
palpitation,
flushing,
hypotension,
nasopharyngitis,
epistaxis,
headache,
myalgia,
back and limb pain, increased uterine
bleeding,
blurred vision,
facial oedema,
rash;
less
commonly
tachycardia, hypertension,
seizures,
amnesia,
priapism,
hyperhidrosis;
also reported
unstable angina,
arrhythmia, myocardial infarction,
stroke,
hearing loss,
non-arteritic anterior ischaemic
optic neuropathy,
retinal vascular occlusion,
visual
field defect,
Stevens-Johnson syndrome
Dose
.
ADULT
over 18 years, 40 mg once daily
Adcirca
c
(Lilly) T A
Tablets
, f/c, tadalafil 20 mg (orange), net price 56-tab
pack = £491.22
2.5.2
Centrally acting
antihypertensive drugs
Methyldopa is a centrally acting antihypertensive;
it
may be used for the management
of
hypertension in
pregnancy. Side-effects are minimised if the daily dose is
kept below 1 g.
Clonidine has the disadvantage that sudden withdrawal
of treatment may cause severe rebound hypertension.
Moxonidine, a centrally acting drug, is licensed for mild
to moderate essential
hypertension.
It may have a role
when thiazides,
calcium-channel
blockers,
ACE inhi-
bitors,
and beta-blockers are not
appropriate or have
failed to control blood pressure.
110
2.5.2 Centrally acting antihypertensive drugs
BNF 61
2
Cardiovascular system