Ca Channel blockers Flashcards Preview

Cardiovascular system > Ca Channel blockers > Flashcards

Flashcards in Ca Channel blockers Deck (13)
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1
Q

Mechanism of action?

A

They decrease Ca entry into vascular &cardiac cells.

  • This causes relaxation &vasoldiation in the arterial smooth muscle, lowering arterial pressure.
  • In the heart, they reduce myocardial contractility, they suppress cardiac conduction, particularly across the AV node; slowing the ventricular rate. Reduced cardiac rate, contractility &afterload decreases the myocardial oxygen demand which prevents angina.
2
Q

Angina?

A

Angina pectoris is a type of chest pain caused by reduced blood flow to the heart. It is a symptom of coronary artery disease, often described as squeezing, pressure, heaviness, tightness or pain in the chest.

3
Q

What are the two classes of Ca channel blockers?

A
  • Dihydropyridines : relatively selective for the vasculate.

* Non-dihyrdopyridines : mostly selective for the heart

4
Q

Dihydropyridines drugs?

A

Amlodipine, Nifedipine (ADALATE), Barnidipine, Clevidipine, Felodipine (FLODIL), Isradipine, Lacidipine, Lercanidipine (ZANIDIP), Manidipine, Nicardipine (LOXEN), Nisolidipine, Nitrendipine (BAYPRESS).

Living room : Isra is a Clever Fellow, Barni &Mani on the sofas. Lercani on the window, tables : Nitren &Nisoli. Laci on the carpet. Nicar LOXEN on the chair relaxing. Nife &Amlo are famous needless to assign them to loci.

5
Q

Non-dihydropyridines drugs?

A

Verapamil, the most cardioselective.

Diltiazem; has some effect on the vessels.

6
Q

Indications?

A
  • Amlodipine, and to a lesser extent, Nifedipine are used as first/second line treatment for hypertension to reduce risk of stroke, myocardial infarction &death from cardiovascular diseases.
  • all Ca channel blockers are used to control symptoms of stable angina.
  • non-dihydropyridines are used to control cardiac rate in supraventricular arrhythmias : AF, atrial flutter and SVT.
7
Q

Important AE?

A
  • dihydropiridines : ankle swelling, flushing, headache, palpitations : caused by vasodilation &the compensatory tachycardia.
  • non-dihydropyridines : Verapamil : constipation &less often, but more seriously : bradycardia, heart block &cardiac failure. while Diltiazem can cause both vasodilation issued problems &heart related side effects.
8
Q

Why should Dihydropyridines be avoided in unstable angina ?

A

Vasodilation induces a reflex increase in contractility (compensatory tachycardia) which can offput &increase myocardial oxygen demand.

9
Q

Why should Non-dihydropyridines not be used in combination with beta blockers (except under specialist supervision)?

A

both are negatively inotropic &chronotropic : bradycardia, heart failure &asystole (cardiac arrest rhythm, the heart isn’t functioning)

10
Q

Plasma half-life of Amlodipine?

A

35-50 hours (the longest amongst Ca channel blockers)

All Ca channel blockers (&ACE) are advised to take the morning.

If you have many antihypertensive drugs, take some the morning, some the evening at bedtime.

11
Q

Plasma half-life of Nifedipine?

A

2-3 hours

12
Q

Plasma half-life of Verapamil?

A

2-8 hours

13
Q

Plasma half-life of Diltiazem?

A

6-8 hours