Transcript The Pharmacological Management of Hypertension

Altaz Dhanani
Medicines Management Pharmacist, Supplementary Prescriber
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Drug Treatment of Hypertension
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General points on treating Hypertension
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Questions???
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A modifiable risk factor
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Do not view in isolation
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Don’t forget lifestyle advice
Intervention
Avg reduction in % with 10mmHg
SBP & DBP
reduction in SBP
(<1 year)
Other
Comments
(from NICE
2006)
Diet (Healthy, Low
calorie)
5-6mmHg
~40%
Avg wt changes 29Kg
Exercise (Aerobic,
30-60mins, 35x/week)
2-3mmHg
~30%
Relaxation Therapy
(Structured)
3-4mmHg
~33%
Cost & availability to
PCO unknown
Multiple
Interventions
4-5mmHg
~25%
Education alone unlikely
to be effective
Alcohol Reduction
3-4mmHg
~30%
Salt Reduction
(<6g/day)
2-3mmHg
~25%
Effects diminish over
time (2-3yrs)
Other: Caffeine (> 5cups/day inc BP by ~2-1mmHg, Smoking (per se) no effect on BP.
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BP consistently ≥ 160/100
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BP consistently ≥ 140/90 AND
◦ with existing CVD
or
◦ target organ damage
or
◦ raised CVD Risk of 20% or more
NICE
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140/90
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140/80 for type 2 diabetics
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135/75 for type 2 diabetics with
microalbuminuria or proteinuria
135/85 for type 1 diabetics (130/80 with
nephropathy)
Step 1
<55 years
A
≥55 years or Black
C or D
Step 2
A + C or A + D
Step 3
A+C+D
Step 4
A+C+D
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Further diuretic therapy or α-blocker or β-blocker
Consider specialist advice
A=ACEi (ARB if intolerant), C= calcium channel blocker, D = thiazide diuretic
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Ramipril, lisinopril, perindopril and others
Works by manipulating the renin-angiotensin system
Renin to angiotensin to angiotensin 2 via angiotensin
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Angiotensin 2 = potent vasoconstrictor
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converting enzymes
Hence
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ACEi’s inhibit the action of the angiotensin converting
enzymes and prevent the conversion of angiotensin to
angiotensin 2
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Persistent dry cough
Hyperkalaemia
Worsening renal failure
Angiodema
Hypotension (1st dose)
Rash, neutropenia....
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Hypersensitivity to ACEi (incl. Angiodema)
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Pregnancy
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Renal insufficiency
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Hyperkalaemia
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K+ sparing diuretics and aldosterone
antagonists (spironolactone) – severe
hyperkalaemia
Lithium – lithium excretion ↓
Ciclosporin - ↑ risk of hyperkalaemia
K+ salts - ↑ risk of severe hyperkalaemia
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Generally recommended for people < 55 yrs
and Caucasian
In diabetes, ACEi’s are an appropriate 1st line
choice
Caution when initiating, 1st dose hypotension
esp. with pts on concomitant diuretic therapy
first dose at night
Monitor U&E’s before initiation and regular
monitoring during treatment
Preferred Rx’ing drugs......
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Losartan, Valsartan, Irbesartan etc
Effects similar to ACEi’s
Works by blocking angiotensin 2 (potent
vasoconstrictor) from entering receptors in
the smooth muscles of blood vessels
Primarily SHOULD only be considered where
an ACEi is indicated but not tolerated
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Hyperkalaemia
Angiodema
Symptomatic hypotension – dizziness or
light-headedness
Contra-indications
 Pregnancy
Hepatic impairment for some agents
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Much the same as the ACEi’s
Telmisartan ↑ plasma concentration of
digoxin
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SHOULD only used where an ACEi is
indicated but not tolerated
NO compelling evidence to suggest they offer
any clinical advantage over ACEi’s
No compelling evidence that there are
differences between individual agents
Considerably more costly than ACEi’s
Monitoring as per ACEi’s
Preferred Rx’ing drugs.....
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Amlodipine, Felodipine, Nifedipine etc
Can be split into 2 groups dependant on their
properties:
◦ Dihydropyridines (e.g. amlodipine)
◦ Non-dihydropyridines (diltiazem, verapamil)
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Dihydropyridines potent vaso-dilators, relax
the vascular smoothe muscle and dilates the
arteries
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Flushing
Headache
Dizziness
Ankle swelling
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Theophylline - ↑ plasma conc of theophylline
Ciclosporin – plasma conc ↑
Digoxin – plasma conc ↑
Antifungals - ↑ plasma conc of
dihydropyridines
Grapefruit Juice - ↑ plasma conc of
dihydropyridines (though not as significant
an interaction as with simvastatin)
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Equal 1st line choice with thiazide diuretics
for pts ≥ 55yrs or pts who are of African or
Caribbean descent
What about previous concerns over CCB’s re:
that CCB’s increase risk of CV events
independent of their BP lowering effect?
Immediate release formulations should be
avoided (e.g. Non m/r nifedipine)
m/r formulations should be Rx’ed by brand
name (nifedipine and diltiazem versions)
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Bendroflumethiazide, Indapamide e.t.c.
Stop the resorption of sodium hence
promoting its excretion leading to more urine
being produced. Flushes excess fluids and
minerals from the body
Act within 1-2 hours of administration and
generally have a duration of action of 12-24
hours
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Hypokalaemia
Postural hypotension
Impotence
Mild GI effects
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Cardiac glycosides – hypokalaemia caused by
diuretics increases cardiac toxicity
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Ciclosporin - ↑ risk of nephrotoxicity
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Lithium - ↑ plasma conc.
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Considered as equal first line choice with
CCB’s for black pts or aged 55 yrs and over
Due to low acquisition costs of these drugs,
may be used preferentially over CCB’s
Low doses of thiazides produce maximal or
near-maximal BP lowering with little
biochemical disturbance (higher doses confer
little advantage in BP control but disturbs
plasma concs of K+, Na+, uric acid, glucose
and lipids!)
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Atenolol, metoprolol e.t.c.
Not exactly known how they work in
hypertension – but they ↓ cardiac output, and
block the action of stress hormones that
constrict the blood vessels in the heart, brain
and body
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Bradycardia
Shortness of breath
Coldness of extremities
CNS effects with lipid soluble drugs
(propranolol)
Impotence
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Asthma/severe COPD
Marked bradycardia
Severe peripheral artery disease
Heart Block
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No longer recommended first line treatment
BUT they are an option for:
◦ Younger patients with C/I’s for ACEi’s or ARB’s
◦ Women of child bearing potential
◦ Pts with compelling indications for their use (e.g.
ischaemic heart disease)
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Best avoided in combination with thiazide
diuretics
NICE
 If BP controlled....no absolute need to replace
the BB with an alternative
 If BP not controlled, revise treatment
according to treatment algorithm
 When a BB is withdrawn, step the dose down
gradually
 Do not withdraw if there are compelling
indications for being treated with one
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NICE guidance on drug treatment NOT based on
large clinical outcome studies – based on sound
pathophysiological grounds and expert opinion
Do not forget lifestyle advice – to be offered on
an ongoing basis
If drug intervention is needed, follow NICE
algorithm unless there are compelling indications
to do otherwise
Most patients will need more than 1 drug to
control BP??
Β-Blockers do have a role in hypertensive
therapy, but in limited circumstances
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Remember treatment targets – but bear in
mind it won’t be possible for all pts to
achieve
Any lowering of BP is beneficial – esp. those
at highest baseline CVD risk
Account for patients’ tolerability and
concordance when reviewing treatment
response
All patients should have at least an annual
review of care
Does the pt really need drug therapy
1.
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2.
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Check your measuring technique
Measure several readings over a period of time
Review all potential drug causes and try non-drug therapies
first (unless BP really high)
Attend to other risk factors – smoking, lipids etc
If treatment is necessary, getting the pressure
down is more important than worrying too much
about which drug to use
Thiazides are first choice for most people, CCB’s probably less
so, doxazosin (α-blocker) first choice for almost no one!
Treat the patient, not the blood pressure
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A drug that is not taken will not work and is the most expensive
medication
Potential benefits of aggressive therapy with multiple drugs
must be weighed against the acceptability to the patient of such
therapy