page131
CLONIDINE HYDROCHLORIDE U
Indications
hypertension;
migraine (section 4.7.4.2);
menopausal flushing (section 6.4.1.1)
Cautions
must be withdrawn gradually to avoid severe
rebound hypertension;
Raynaud’s syndrome or other
occlusive peripheral vascular disease; history of
depression;
interactions: Appendix 1 (clonidine)
Driving
Drowsiness may affect performance of skilled tasks
(e.g. driving); effects of alcohol may be enhanced
Pregnancy
may lower fetal heart rate,
but risk should
be balanced against risk of uncontrolled maternal
hypertension;
avoid intravenous injection
Breast-feeding
manufacturer advises avoid—present
in milk
Side-effects
dry mouth,
sedation,
depression,
fluid
retention,
bradycardia,
Raynaud’s phenomenon,
headache, dizziness, euphoria, nocturnal unrest, rash,
nausea,
constipation,
rarely impotence
Dose
. By mouth,
50–100 micrograms 3 times daily,
increased every second or third day; usual max. dose
1.2 mg daily
Catapres
c
(Boehringer Ingelheim) A U
Tablets
,
scored,
clonidine hydrochloride 100 micr-
ograms,
net price 100-tab pack = £5.32;
300 micr-
ograms,
100-tab pack = £12.39.
Label:
3,
8
Dixarit
c
AU
Section 4.7.4.2
METHYLDOPA
Indications
hypertension
Cautions
monitor blood counts and liver-function
before treatment and at intervals during first 6–12
weeks or if unexplained fever occurs;
history of
depression; positive direct Coombs’ test in up to 20%
of patients (may affect blood cross-matching);
inter-
ference with laboratory tests; interactions: Appendix
1 (methyldopa)
Driving
Drowsiness may affect performance of skilled tasks
(e.g. driving); effects of alcohol may be enhanced
Contra-indications
depression, phaeochromocytoma;
acute porphyria (section 9.8.2)
Hepatic impairment
manufacturer advises caution in
history of liver disease; avoid in active liver disease
Renal impairment
start with small dose;
increased
sensitivity to hypotensive and sedative effect
Pregnancy
not known to be harmful
Breast-feeding
amount too small to be harmful
Side-effects
gastro-intestinal disturbances,
dry
mouth,
stomatitis,
sialadenitis;
bradycardia,
exacer-
bation of angina,
postural hypotension, oedema;
sedation,
headache,
dizziness,
asthenia, myalgia,
arthralgia, paraesthesia,
nightmares,
mild psychosis,
depression,
impaired mental acuity,
parkinsonism,
Bell’s palsy;
hepatitis,
jaundice; pancreatitis;
haemo-
lytic anaemia;
bone-marrow depression,
leucopenia,
thrombocytopenia,
eosinophilia;
hypersensitivity
reactions including lupus erythematosus-like
syndrome, drug fever, myocarditis, pericarditis; rashes
(including toxic epidermal necrolysis);
nasal conges-
tion, failure of ejaculation,
impotence,
decreased libi-
do,
gynaecomastia,
hyperprolactinaemia,
amenor-
rhoea
Dose
. Initially 250 mg 2–3 times daily, increased gradually at
intervals of at least 2 days,
max.
3 g daily;
ELDERLY
initially 125 mg twice daily, increased gradually,
max.
2 g daily
Methyldopa
(Non-proprietary) A
Tablets
, coated, methyldopa (anhydrous) 125 mg, net
price 56-tab pack = £16.29;
250 mg,
56-tab pack =
£8.26;
500 mg,
56-tab pack = £11.49.
Label:
3,
8
Aldomet
c
(Iroko) A
Tablets
,
all yellow,
f/c,
methyldopa (anhydrous)
250 mg,
net price 60 = £6.15;
500 mg,
30 = £4.55.
Label:
3,
8
MOXONIDINE
Indications
mild to moderate essential hypertension
Cautions
avoid abrupt withdrawal (if concomitant
treatment with beta-blocker has to be stopped,
dis-
continue beta-blocker first,
then moxonidine after a
few days); severe coronary artery disease;
unstable
angina; first-degree AV block; moderate heart failure;
interactions: see Appendix 1 (moxonidine)
Contra-indications
conduction disorders (sick sinus
syndrome,
sino-atrial block,
second- or third-degree
AV block); bradycardia; severe heart failure
Renal impairment
max.
single dose 200 micrograms
and max. daily dose 400 micrograms if eGFR 30–
60 mL/minute/1.73 m
2
;
avoid if eGFR less than
30 mL/minute/1.73 m
2
Pregnancy
manufacturer advises avoid—no informa-
tion available
Breast-feeding
present in milk—manufacturer
advises avoid
Side-effects
dry mouth,
diarrhoea,
nausea,
vomiting,
dyspepsia,
dizziness,
somnolence,
insomnia, back
pain,
rash,
pruritus;
less commonly
bradycardia,
tin-
nitus,
angioedema,
oedema,
nervousness,
neck pain
Dose
. 200 micrograms once daily in the morning, increased
if necessary after 3 weeks to 400 micrograms daily in
1–2 divided doses;
max.
600 micrograms daily in 2
divided doses (max.
single dose 400 micrograms)
Moxonidine
(Non-proprietary) A
Tablets
,
f/c,
moxonidine 200 micrograms,
net price
28-tab pack = £3.76; 300 micrograms, net price 28-tab
pack = £4.82; 400 micrograms, net price 28-tab pack =
£5.01.
Label:
3
Physiotens
c
(Solvay) A
Tablets
,
f/c,
moxonidine 200 micrograms (pink), net
price 28-tab pack = £9.72;
300 micrograms (red),
28-
tab pack = £11.49; 400 micrograms (red), 28-tab pack
= £13.26.
Label:
3
2.5.3
Adrenergic neurone
blocking drugs
Adrenergic neurone blocking drugs prevent the release
of
noradrenaline from postganglionic adrenergic neu-
rones. These drugs do not control supine blood pressure
and may cause postural
hypotension.
For this reason
they have largely fallen from use, but may be necessary
with other therapy in resistant hypertension.
BNF 61
2.5.3 Adrenergic neurone blocking drugs
111
2
Cardiovascular system