AF drugs BBlockers, CCBS

Question 1

Beta Blockers examples

Answer 1

Bisoprolol, propanolol (lipid soluble so crosses BBB) and atenolol

Question 2

BB MOA

Answer 2

B1 adrenoreceptors which are located mainly in the heart: here they reduce the force of contraction and speed of conduction in the heart> relieves myocardial ischaemia by reducing cardiac work and oxygen demand and increasing myocardial perfusion. A-O Beta blockers
B2 adrenoreceptors are found mostly in the smooth muscle of blood vessels and the airways. P-Z beta blockers

In AF: They slow the ventricular rate in AF by prolonging the refractory period of the AVN
HTN: They lower blood pressure by reducing renin secretion from the kidney as this is mainly mediated by B1 receptors

Question 3

Define the following:
Positive chronotropy
Positive dromotropy 
Positive Inotropy 
Positive lusitropy

Answer 3

Positive chronotropy: SA node
Positive dromotropy: increases conduction
Positive Inotropy: increases contraction
Positive lusitropy: increases relaxation of the atria and ventricle

Question 4

BB Clinical indications

Answer 4

IHD: First line option to improve symptoms and prognosis associated with angina and ACS
CHF: 1st line
AF: 1st line to reduce ventricular rate and in paroxysmal AF to maintain sinus rhythm
SVT: 1st line in patients without circulatory compromise to restore sinus rhymthm
HTN: Not first line but may be used when other medicines e.g. CCBs, ACEIs, Thiazide diuretics are insufficient or inappropriate

Question 5

Dose of BBs?

Answer 5

Can be taken as an oral or IV prep

• HTN: 25MG-50MG QD
• Angina: 100mg QD= ½ divided doses
• Arrythmias: 50-100mg QD
• IV injection: 2.5mg every 5 minutes if required. 1mg/minute. Max 10mg per course

Question 6

BB Contraindications

Answer 6

Asthma patients: Can cause life threatening bronchospasm so should be avoided. This is due to blockage of B2 adrenoreceptors in the airways
They are usually safe in COPD patients
HF: They should be started at a low dose and increased slowly as they may initially impair cardiac function
Haemodynamic instability: Should be avoided
Heart Block: Contraindicated
Hepatic failure: Dosage reduction of beta blocker required
In elderly:
- With bradycardia: type 2 heart block or complete heart block may occur
- With frequent hypoglycaemic episodes: risk of supressing hypoglycaemic symptoms

Question 7

BB side effects

Answer 7

Fatigue 
Cold extremities 
Headache 
GI disturbance e.g. Nausea 
Sleep disturbance and nightmares
May cause impotence in men: cannot achieve an erection or orgasm 
Rare: Hallucination

Question 8

BB interactions

Elimination?

Answer 8

Must not be used with Non-dihydropyridine CCBs e.g. diltiazem and verapamil: this combination can cause HF, bradycardia and even asystole
B-BLOCKER +Diltiazem/Verapamil= NO GO!!!

Excreted unchanged in the urin

Question 9

Communicate what the BBlockers are for to a pt

Answer 9

Explain: This drug is being prescribed to help with *state clinical indication. Warn the patient of common side effects e.g. impotence where relevant. Warn patient about initial deterioration of their symptoms and advise them to seek help if this occurs.
Warn patients with Obstructive airway disease to stop treatment and seek urgent advice if they develop breathing difficulties

Success: Reduction in symptoms, dose adjust accordingly