Trade name(s): Cardiazem
Drug Class:Calcium-Channel Blocker
Theraputic use:
THis is used as a depression of Sa and AV node conduction as well as reduced inotrophy and chronotropy of cardiac contraction.
it is used as an antiarrhythmic and an antihypertensive
Pharmacological action:
Pharmacokinetics:
-
Administration
Well absorbed from the GI tract extensive first pass effect given oral delivery 40% of total. -
Distribution
70-80% binding to plasma proteins. -
Metabolism
Extensive metabolism in which 2-4% of the unchanged drug appears in urine.
Plasma elimination half life is 3-4.5 hours.
Departure of linearity with increased dose in conventional and SR tablets
Minimum theraputic concentration is around 50-200 ng/mL
- Excretion
mostly excreted in urine
Indications:
- Angina, hypertension, atrial fibrillation, atrial flutter, paroxysmal supra ventricular tachycardia
Contraindications:
severe bradycardia, hypotension, left ventricular failure with pulmonary congestion, acute MI with pulmonary congesiton, heart failure with reduced ejection fraction 2nd or 3rd degree AV block or sick sinus stsrome, concomitant dantrolene, ivabradine, pregnancy, breastfeeding
Precautions:
Significantly impaired left ventricular function brady cardia, first degree AV block prolonged PR-interval, patients at risk of intestinal obstruction, elderlym diabetes mellitus, bronchial hypersensetitivy, avoid abrupt withdrawl in patients with angina
Adverse reactions:
mostly form over cooking dose
- brady cardia
- SA block
- AV block
- palpitation, dizziness, hypetension, malaise, asrthenia, headache, hot flushes, GU disturbances, oedema
Interactions:
dantrolene - hyperkalaemia
vabradine
and a number od -tinib drugs
There are lots and lots of interactions
Dosing/Current guidelines:
Angina
Oral tablet immediate release
Adult 30 mg 3–4 times daily (elderly initially twice daily) increased if necessary to 240 mg daily in divided doses max 360 mg daily
Oral, modified release
Adult 120–180 mg once daily, increased if necessary at intervals of 7–14 days; maximum 360 mg daily
Hypertension
Oral, modified release
Adult 180–240 mg once daily, increased if necessary every 14 days; usual maintenance 240–360 mg once daily
Atrial fibrillation or atrial flutter (ventricular rate control)
Oral, immediate release
Adult 60 mg 3 times daily, increased if necessary to maximum 360 mg daily in 3 or 4 divided doses
Oral, modified release
Adult 120–180 mg daily, increase if necessary to maximum 360 mg daily
Slow intravenous injection
Adult 250 micrograms/kg (usual maximum 20 mg) over 2 minutes; if inadequate response after 15 minutes a second bolus of 350 micrograms/kg (usual maximum 25 mg) may be given over 2 minutes; subsequent bolus doses should be individualised, or a continuous intravenous infusion started
Continuous intravenous infusion
Adult following intravenous bolus dose, initially 10 mg/hour (some patients may respond to 5 mg/hour); increase if necessary in steps of 5 mg/hour to maximum 15 mg/hour; continue for maximum 24 hours
Paroxysmal supraventricular tachycardia (cardioversion)
Intravenous injection
Adult 250 micrograms/kg (usual maximum 20 mg) over 2 minutes; if inadequate response after 15 minutes a second bolus 350 micrograms/kg (usual maximum 25 mg) may be given over 2 minutes; subsequent bolus doses should be individualised, or a continuous intravenous infusion started
Continuous intravenous infusion
Adult following intravenous bolus dose, initially 10 mg/hour (some patients may respond to 5 mg/hour); increase if necessary in steps of 5 mg/hour to maximum 15 mg/hour; continue for maximum 24 hours
Monitoring:
Overdose:
oral ld50 in mice and rats are 415-740 and 560 and 810 respectively
the intraventous dose were 60 and 38 respectively.
OD may result in bradycardia, high degree AV block, cardiac fialur, and hypotension etc
use supportive treatment or drug treatment
Treatment of OD:
atropine fluid and vasopressors have been used
inotropic agents also used
in general
ventilator support, gastric lavage activated charcoal, intravenous calcium (unsure if helps or not)
Bradycardia
Administer atropine (0.60 to 1.0mg). If there is no response to vagal blockade administer isoprenaline cautiously.
High Degree AV Block
Treat as for bradycardia above. Fixed high-degree AV block should be treated with cardiac pacing.
Cardiac failure
Administer inotropic agents (isoprenaline, dopamine, or dobutamine) and diuretics.
Hypotension
Vasopressors (e.g. dopamine or noradrenaline acid tartrate). Actual treatment and dosage should depend on the severity of the clinical situation and the judgement and experience of the treating physician. Symptoms and signs of overdose may be delayed due to the controlled release properties of the product, so patients should be kept under observation for at least 24 hours.
Pregnancy
Subsidised?
modified release capsule is fully subsidised (diltiazem dc (clinect), cardiazem CD)
What to tell patients:
Comments/Observations/notes: