6.4.6 - Calcium Channel Blockers

Front 1

Calcium Channel Blockers
- Drugs in class

Back 1

1. Verapamil
2. Diltiazem
3. Dihydropyridines
(a) amlodipine
(b) nifedipine
(c) felodipine
(d) lecarnidipine
(e) nimodipine

Front 2

Calcium channel blockers
- MOA

Back 2

Block inward current of calcium into cells. This reduces vascular smooth muscle contraction, and reduce heart rate and conduction

Front 3

CCBs
- Indications
- Indication for nimodipine
- Indication for verapamil

Back 3

1. Hypertension
2. Angina & vasospasm (e.g. post CABGs)

Nimodipine may prevent cerebral ischaemic damage from vasospasm after subarachnoid haemorrhage

Verapamil: rate control of AF, prevent and treat SVT

Nifedipine: threatened preterm labour (tocolytic)

Front 4

1. Relative duration of action of dihydropyridines & onset of action
2. Special instructions for verapamil?

Back 4

1. Nifedipine and felodipine have shorter half-lifes. CR preparations are available so that they are only dosed daily.
Felodipine and amlodipine have a faster onset of action (even though nifedipine is used as a tocolytic)

2.
(a) Care with alcohol initially. May prolong it's effect.
(b) Label 13
(c) Label B: with food: applies to the SR tablets but not to the IR tabs or Veracaps
(d) Veracaps can be sprinkled over APPLE SAUCE prn
(e) the SR tabs can be halved (240-->120) if individuals are sensitive.

Front 5

Use of CCBs in HTN
1. CF other AHs in the elderly?
2. In HF?

Back 5

1. In the elderly, felodipine and long acting nifedipine are as effective as diuretics and BBs
2. Amlodipine and felodipine have been shown not to increase morbidity in HF

Front 6

CCBs in angina
- how do they compare to other treatments?

Back 6

- as effective as BBs but only CR verapamil has been shown to decrease cardiovascular events

Front 7

CCBs
- CIs
- BF/Preg

Back 7

CI: cardiogenic shock; Verapamil and diltiazem also CI in severe bradycardia(v), AV block, severe hypotension

- Preg Cat C: maternal hypotension may cause fetal hypoxia
BF: Nifedipine "seems safe", rest have ltd or no data

Front 8

CCBs:
- Adverse effects
- management of the obvious one

Back 8

Common
- HEADACHE, FLUSHING, FATIGUE, PERIPHERAL OEDEMA (for V+D AND dihydropyridines
- gingival hyperplasia (rare for v,d)
- bradycardia (v,d only)
- constipation (v - others infrequent)

Do not treat peripheral oedema with diuretics, may cause volume depletion

Front 9

Amlodipine
- brands, dose forms, doses

Back 9

Amlo, Norvasc, Perivasc
5mg.30, 10mg.30

Caduet (PBS-R)
5mg with 10/20/40/80
10mg with 10/20/40/80

Dose: 5mg-10mg daily (start at 2.5 if old or HI)

Front 10

Felodipine
- brands, dose forms, doses
- Special instructions

Back 10

Felodur ER, Plendil ER, Felodil XR
2.5mg, 5mg, 10mg.30 enteric coated tablets
2.5-20mg d (start on 2.5 if old or HI)

- Swallow whole(A), L18, L5, L9, L12 (on initiation)

**NB: they make a 2.5mg because you can't halve it!!!

Front 11

Lecarnidipine
- brands, dose forms, doses
- When can you increase dose (remember time to onset on action)
- Extra contraindications

Back 11

Zanidip, 10mg/20mg.30 tabs

10-20mg d (increase after 2 weeks)

CI in RI <12ml/min, severe hepatic impairment & manufacturer CI with cyclosporin

Front 12

Nifedipine
- brands, dose form, doses
- Dose equivalence

Back 12

Adalat, Adefin, Nyefax(20mg)
10mg.60, 20mg.60 TABS

20mg.30, 30mg.30, 60mg.30 CR tabs: Adalat Oros, Addos XR, Adefin XL

10-40mg bd
20-90mg d (CR), max 90mg angina, max 120mg HTN

To change, calc daily dose and choose the closest CR tab d.

Front 13

Nimodipine
- brand, dose form, doses
- indications
- pbs listin

Back 13

Nimotop
30mg.100 tab, 0.2mg/ml injection

For prevention and treatment of ischaemic deficits following subarachnoid haemorrhage ONLY
Not on PBS

Front 14

Verapamil
- brand, dose forms, dose

Back 14

40mg.100, 80mg.100, 120mg.100, 160mg.60 (Isoptin, Anpec)

180mg.30, 240.30 CR tab (Isoptin SR, Cordilox SR, Anpec SR)

160mg.30, 240mg.30 CR CAPS (Veracaps SR)

2.5mg/mL.2mL inj (Isoptin)

240mg/4mg.28 CR tab for HTN(Takra,with trandolapril)

IR tab: start of 80mg bd-tds, then maintain on 160mg bd-tds
CR tab: 120-240 HTN (160-240 for angina) d. Max 240mg bd.
Arrythmia: doses as above (120-480mg d)

Front 15

Diltiazem
- brands
- dose forms
doses

Back 15

60mg.90 tab (Vasocardol, Cardizem, Coras, Dilzem, Diltahexal)
180mg.30, 240mg.30, 360mg.30 SR CAP (Cardizem CD, Vasocardol CD, Dilzem CD, Diltahexal CD)

Doses
HTN: 180-360mg d (SR only)
Angina: 30mg tds-qid (max 240mg d)
Angina CR: 180-360mg d

Front 16

How should CCB induced peripheral oedema be treated?

Back 16

It shouldn't. Treatment may put patients at risk of volume depletion.

Front 17

CCB DIs
(a) applying to all drugs in class
(b) applying to verapamil and diltiazem
(c) just verapamil

Back 17

(a) decreasing BP
(b)
- inhibitors of CYP3A4 (avoid with atorvastatin, simvastatin, buspirone, Calcineurin inhibitors, CBZ, phenytoin, imipramine=heartblock,
- metabolised by CYP3A4 (avoid cimetidine, rifampicin
- slow cardiac conduction and causes bradycardia
(c)
- antiarhythmics: increased risk of bradycardia, HF, arrhythmia; AVOID
- avoid Beta-blockers, INCLUDING EYE DROPS, unless under specialist supervision

Front 18

CCBs
Which labels go on which CCBs?

Back 18

All have label 18, except: amlodipine, diltiazem (verapamil does have it!)

All also have: label 9, 12+ (if new but verapamil has a permanent label 12)

Some have label A (swallow whole): e.g. SR felodipine, nifedipine, diltiazem, verapamil N.B. veracaps can be opened and sprinkled prn

Label 5: felodipine (affected by both inhibitors and inducers of CYP3A4)

Verapamil also has: 13, and B (which formulations?) & may increase and prolong the effects of alcohol in some people - limit EtOH until you know how you are effectes

Front 19

CCBs - DIs
(e) nifedipine

Back 19

- potent CYP3A4 inhibitors increase conc
- increases effect of MgSO4 (eclampsia / tocolytic)
- increases conc of digoxin

Front 20

CCBs - DIs
(f) lecarnidipine

Back 20

- CYP3A4 inhibitors
- metoprolol DECREASES lecarnidipine concentration and MAY reduce activity

Front 21

CCBs - DIs
(g)felodipine

Back 21

- CYP3A4 inhibitors and inducers....nb.. label 5

Front 22

CCBs - DIs
amlodipine

Back 22

ALMOST NONE
- cyclosporin conc may be increased