Beta-adrenoceptor blocking drugs Flashcards
Which organs/structures do do beta-blockers block the beta-adrenoceptors in? (5)
Heart Peripheral vasculature Bronchi Pancreas Liver
What does it mean if a beta-blocker has intrinsic sympathomimetic activity (ISA)?
Partial agonist activity: represents the capacity of beta-blockers to stimulate as well as to block adrenergic receptor
They cause less bradycardia and coldness of extremities than other beta-blockers
Beta-blockers with intrinsic sympathomimetic activity (ISA):
- Celiprolol hydrochloride
- Pindolol
- Acebutolol
- Oxprenolol hydrochloride
Name 4 beta-blockers which have intrinsic sympathomimetic activity (ISA)?
- Celiprolol hydrochloride
- Pindolol
- Acebutolol
- Oxprenolol hydrochloride
ISA = Partial agonist activity: represents the capacity of beta-blockers to stimulate as well as to block adrenergic receptor
They cause less bradycardia and coldness of extremities than other beta-blockers
What is the benefit of prescribing beta-blockers with intrinsic sympathomimetic activity (ISA)?
Cause less bradycardia and coldness of extremities than other beta-blockers
ISA = Partial agonist activity: represents the capacity of beta-blockers to stimulate as well as to block adrenergic receptor
Beta-blockers with intrinsic sympathomimetic activity (ISA):
- Celiprolol hydrochloride
- Pindolol
- Acebutolol
- Oxprenolol hydrochloride
What is the one indication to use celiprolol hydrochloride?
Mild to moderate hypertension
- Oral: 200 mg once daily, increased to 400 mg once daily if necessary
What are 12 contraindications to the use of beta-blockers?
- Asthma
- Cardiogenic shock
- Hypotension
- Marked bradycardia
- Metabolic acidosis
- Phaechromocytoma (except with alpha-blocker)
- Prinzmetal’s angina
- Second degree AV block
- Third-degree AV block
- Sick sinus syndrome
- Uncontrolled heart failure
- Peripheral arterial disease
Which AV blocks are contraindications to beta-blockers?
Second- and third-degree AV block
First-degree AV block is a caution to give beta-blockers
When an elderly patient is taking a beta-blocker in which conditions should consider may be potentially inappropriate (STOPP criteria)?
- In combination with verapamil or diltiazem
- With bradycardia (HR < 50), type II heart block, or complete heart block
- In diabetes mellitus patients with frequent hypoglycaemic episodes
- If prescribed a non-selective beta-blocker in a history of asthma requiring treatment
What is the risk of combining a beta-blocker with verapamil or diltiazem?
Risk of heart block
What is the risk of giving beta-blockers to a patient with either bradycardia (HR < 50), type II heart block or complete heart block?
Risk of complete heart block and asystole
What is the risk of giving a beta-blocker to patients with diabetes mellitus?
Risk of suppressing hypoglycaemic symptoms
Diabetes is a caution NOT a contraindications
BUT in elderly patients with frequent hypoglycaemic episodes the beta-blocker may be inappropriate
What is the risk of giving a beta-blocker (including cardioselective beta-blockers) to patient with a history of asthma, bronchospasm or obstructive airways disease?
Bronchospasms
BUT if there are no alternative, a cardioselective beta-blocker can be given to these patients with caution and under specialist supervision
Beta blockers can mask symptoms of which two conditions?
Hypoglycaemia
Thyrotoxicosis
Which drink greatly decreases the exposure to the beta blocker celiprolol?
Orange juice
What are the common side effects of beta-blockers? (21)
- Abdominal discomfort
- Bradycardia
- Confusion
- Depression
- Diarrhoea
- Dizziness
- Dry eye (reversible on discontinuation)
- Dyspnoea
- Erectile dysfunction
- Fatigue
- Headache
- Heart failure
- Nausea
- Paraesthesia
- Peripheral coldness
- Peripheral vascular disease
- Rash
- Sleep disorders (nightmares)
- Syncope
- Visual impairment
- Vomiting
If excessive bradycardia occurs following IV injection of beta-blocker, which drug can be used to counter the effects?
IV atropine sulfate
What are the risks of using a beta-blocker during pregnancy?
- Intra-uterine growth restriction
- Neonatal hypoglycaemia
- Bradycardia
The risk is greater in severe hypertension
Use of celiprolol hydrochloride in renal impairment:
(a) At which creatinine clearance should you reduce the dose of celiprolol?
(b) At which creatinine clearance should you avoid the use of celiprolol?
(a) half dose if creatinine clearance 15-40 mL/minute
(b) Avoid if creatinine clearance is < 15 mL/minute
Why should you avoid abrupt withdrawal of beta-blocker in ischaemic heart disease?
Rebound worsening of myocardial ischaemia
A gradual reduction of dose is preferable when beta-blockers are to be stopped
What are the indication for the use of the beta blocker pindolol? (2)
Hypertension
- Oral: Initially 5 mg 2–3 times a day, alternatively 15 mg once daily, doses to be increased as required at weekly intervals; maintenance 15–30 mg daily; maximum 45 mg per day.
Angina
- Oral: 2.5–5 mg up to 3 times a day.
What are the signs and symptoms of an overdose with beta-blockers?
- Light headedness
- Dizziness
- Bradycardia
- Hypotension
- Syncope (caused by bradycardia and hypotension)
- Heart failure may be precipitated or exacerbated
If beta-blocker was administered with IV injection, excessive bradycardia may be countered with IV atropine sulfate
What are the indications for the use of the beta-blocker acebutolol?
Hypertension
- Oral: Initially 400 mg daily for 2 weeks, alternatively initially 200 mg twice daily for 2 weeks, then increased if necessary to 400 mg twice daily; maximum 1.2 g per day.
Angina
- Oral: Initially 400 mg daily, alternatively initially 200 mg twice daily; maximum 1.2 g per day.
Arrhythmias
- Oral: 0.4–1.2 g daily in 2–3 divided doses.
Severe angina
- Oral: Initially 300 mg 3 times a day; maximum 1.2 g per day.
What is a common side effects of the beta-blocker acebutolol (in addition to the common side effects of all beta-blockers)?
Gastrointestinal disorder
Why is acebutolol not a good choice as a beta-blocker in mothers who are breastfeeding?
Present in breast milk in greater amounts than other beta-blockers
This is a problem with acebutolol and water-soluble beta-blockers