Diltiazem

Brand Names

Cardizem: It includes the active component diltiazem hydrochloride. These are accessible as oral pills. The strengths of these tablets are 30 mg, 60 mg, 90 mg, and 120 mg. The therapeutic benefits of Cardizem are thought to be due to its ability to prevent the inflow of calcium ions during membrane depolarization of cardiac and vascular smooth muscle.

Cartia: It contains a low dose of aspirin 100 mg. It treats blood coagulation and lowers the risk of heart attack and stroke in people with known cardiovascular or cerebrovascular illness.

Matzim: It contains the active ingredients of diltiazem hydrochloride. These are available in the form of extended-release tablets with the strengths of 180 mg, 240 mg, 300mg, 360 mg, and 420 mg. It is used to treat arrhythmics.

Tiadylt : It contains the primary component, diltiazem hydrochloride. These are extended-release capsules with strengths of 120mg, 180mg, 240mg, 300mg, and 360mg. It is used to treat both hypertension and chronic stable angina.

Mechanism of Actions

Diltiazem is a non-dihydropyridine calcium channel blocker. Therapeutic effects arise via a variety of ways. Diltiazem reduces the passage of calcium ions into the heart muscle during depolarization. Reduced intracellular calcium concentration promotes smooth muscle relaxation, which leads to arterial vasodilation and lower blood pressure.

Pharmacokinetics

Absorption

Diltiazem is well absorbed from the GIT and undergoes extensive first-pass metabolism, resultant bioavailability is approximately 40%. The immediate-release diltiazem tablet has an onset of action of 30-60 minutes.

Distribution

The apparent volume of distribution of diltiazem was approximately 305L

Metabolism

Diltiazem is metabolized by the cytochrome P450 system and is an inhibitor of CYP3A4, which can lead to drug-drug interactions. Desacetyl diltiazem, the metabolite of diltiazem, also contributes to coronary vasodilation.

Excretion

The plasma elimination half-life following drug administration is about 3.0 to 4.5 hours. Diltiazem undergoes extensive metabolism in which 2% to 4% of the unchanged drug appears in the urine.

Pharmacodynamics

During depolarization, diltiazem blocks the entry of extracellular calcium ions into the smooth muscle cell membranes of the heart and blood vessels. Diltiazem belongs to the category of negative chronotropes and negative inotropes.

Administration

Diltiazem is available in three forms: tablets, extended-release tablets, and extended-release capsules for oral administration. The standard tablet is often taken three to four times per day. The prolonged release tablets and capsules are often used once or twice a day. I took diltiazem precisely as advised. Do not take more or less of it, or take it more frequently than recommended by your doctor. Do not take more or less of it, or take it more frequently than recommended by your doctor.

Dosage and strengths

In the United States, diltiazem if FDA approved as an oral immediate- release, extended-release, controlled release and intravenous formulation. There are numerous brand names for oral diltiazem, and valuable strengths include 30mg, 60mg, 90mg,120mg, 180mg, 240mg, 300mg, 360mg and 420mg.

Drug interactions

Drug interaction of diltiazem includes

Muscle relaxant- dantrolene

Heart failure- ivabradine

Cholesterol –lowering agents- simavastatin, atorvastatin

Anti-manic drugs-lithium

Blood thinner- warfarin, aspirin,  apixaban, rivaroxaban

Asthma- theophylline, salmeterol:fluticasone, formoterol:budesonide

Beta blockers- metoprolol

Contraindications

Diltiazem is contraindicated to sever hypotension, acute myocardial infarction and pulmonary congestion.

Concurrent administration of beta blockers

Wide complex ventricular tachycardia

Sick sinus syndrome except in the presence of a functioning ventricular pacemaker

Atrial fibrillation or flutter associated with an accessory bypass

Alcohol increases the rate of absorption of diltiazem hydrochloride. Alcohol increases the rate and extent of exposure to diltiazem controlled-release formulation and is associated with dose-related adverse reactions. Advise patients to avoid simultaneous consumption of alcohol with diltiazem.

Side effects

Diltiazem may produce major negative effects: 

• Chest pain, rapid, slow, or irregular heart rate 
• Heart concerns include swelling, rapid weight gain, and feeling short of breath. 
• Liver disorders include loss of appetite, stomach pain, fatigue, itching, and dark urine. 

Common diltiazem side effects include

• edema 
• infections 
• flu symptoms 
• difficulty breathing
• headache
• dizziness 
• weakness 
• slower heart rate, pain, bruising, swelling, or irritation where the drug was injected, nausea, and rash. 

Overdose

Symptoms of overdose includes

• Seizures
• Nausea 
• Slow, fast or irregular heart beat
• Fainting
• Difficulty breathing 
• Dizziness
• Confusion
• Vomiting 
• Increased sweating

Toxicity

Dilitiazem is available in many dosage forms and strengths, making it imperative to be cautious when prescribing, dispensing and administering this medication. There have been reports of diltiazem overdose in amounts ranging from <1gr to 18g. in cases with the known outcome, most patients recovered and in cases with a fatal outcomes, the majority involved multiple drug ingestion.

Storage

Keep out of the children and pets

Store at room temperature between 15 °and 30°C (59 °and 86 °F). Protect  from moisture. Keep the container tightly closed.