Tiazac is the brand name for an extended-release capsule of diltiazem hydrochloride, a medication in the class known as calcium channel blockers. By altering how calcium moves into the cells of the heart and blood vessels, Tiazac helps regulate key cardiovascular functions. This makes it a primary treatment option for managing chronic heart conditions that can lead to serious health complications like heart attack and stroke if left untreated.
Primary Uses of Tiazac (Diltiazem)
The main indications for Tiazac are the treatment of hypertension and the management of chronic stable angina. Its extended-release formulation means it is typically taken once a day, providing continuous control over these conditions.
Tiazac for Hypertension (High Blood Pressure)
High blood pressure is a condition where the force of blood pushing against the walls of arteries is consistently too high. Tiazac helps manage this by producing its antihypertensive effect through the relaxation of vascular smooth muscle, which decreases peripheral vascular resistance. This relaxation allows blood to flow more easily, reducing the pressure on artery walls. Tiazac can be used as a standalone therapy (monotherapy) or in combination with other blood pressure medications. A dose-related response has been demonstrated in clinical trials.
Tiazac for Angina (Chest Pain)
Angina is a type of chest pain caused by reduced blood flow to the heart muscle. Tiazac helps control angina by relaxing the blood vessels of the heart, which increases the supply of blood and oxygen to the cardiac muscle. This reduces the heart's workload and, in turn, decreases the frequency and severity of angina episodes. It is important to note that Tiazac is a preventative treatment and should not be used to treat an acute angina attack. Other medications, like nitroglycerin, are used for immediate relief.
How Does Tiazac Work? The Mechanism of a Calcium Channel Blocker
As a calcium channel blocker, the active ingredient in Tiazac, diltiazem, acts by inhibiting the cellular influx of calcium ions. Here’s a breakdown of its mechanism:
- Vascular Smooth Muscle Relaxation: By inhibiting calcium influx in vascular smooth muscle cells, Tiazac causes the blood vessels to relax (vasodilation). This effect lowers blood pressure by reducing the resistance to blood flow.
- Cardiac Conduction and Rate: Diltiazem affects the heart's electrical conduction system, specifically by slowing down the sinoatrial (SA) and atrioventricular (AV) node conduction. This results in a slower heart rate, which also helps to reduce the heart's workload.
- Negative Inotropic Effect: In addition to slowing the heart rate, diltiazem is a negative inotrope, meaning it decreases the force of contraction of the heart muscle. This further reduces the amount of work the heart must perform to pump blood, which is beneficial in angina management.
Administration and Dosage Guidelines
Tiazac is an extended-release capsule formulation intended for once-daily oral administration. It is crucial to follow a healthcare provider's instructions for dosage and to be consistent with the timing of daily doses.
Key Administration Rules:
- Swallow Whole: The capsule must be swallowed whole to maintain its extended-release mechanism. Crushing or chewing the capsule would cause the medication to be released too quickly, increasing the risk of side effects.
- Applesauce Option: For patients who have trouble swallowing pills, the capsule can be opened and its contents sprinkled onto a spoonful of cool, soft applesauce. The mixture must be swallowed immediately without chewing and followed with a glass of water.
- Once Daily Dosing: The dosage is determined by a healthcare professional based on the individual patient's condition and response to treatment.
Potential Side Effects and Precautions
Like any medication, Tiazac can cause side effects. Some are common and mild, while others can be more serious. Patients should be aware of these and inform their doctor if they occur.
Common Side Effects:
- Headache
- Dizziness or lightheadedness
- Flushing (redness of the face and neck)
- Peripheral edema (swelling of the ankles, feet, or hands)
- Constipation
- Nausea
- Weakness or fatigue
Serious Side Effects (Contact your doctor immediately):
- Slow or irregular heartbeat
- Worsening heart failure symptoms (e.g., shortness of breath, sudden weight gain)
- Liver problems (e.g., yellowing of the skin/eyes, dark urine, severe stomach pain)
- Severe skin reactions (e.g., rash with blistering, peeling skin)
- Fainting
Precautions:
- Tiazac is contraindicated in patients with severe hypotension, certain types of abnormal heart rhythms (e.g., sick sinus syndrome, 2nd or 3rd-degree AV block without a pacemaker), or recent heart attack with pulmonary congestion.
- Use with caution in patients with liver or kidney disease.
- Monitor for signs of heart failure, especially in patients with pre-existing impaired ventricular function.
Tiazac vs. Other Diltiazem Formulations and Alternatives
Tiazac is just one of several brand-name formulations of diltiazem, and they are not all interchangeable. The differences lie in their release profiles, which affect how they are dosed and how they release the medication over time.
| Feature | Tiazac (Extended-Release Capsule) | Cardizem CD (Extended-Release Capsule) | Cardizem LA (Extended-Release Tablet) |
|---|---|---|---|
| Dosing Frequency | Once daily | Once daily | Once daily |
| Administration | May be sprinkled on applesauce | Must be swallowed whole | Must be swallowed whole |
| Formulation | Capsules containing extended-release beads | Capsules | Tablets |
| Interchangeability | Not interchangeable with other diltiazem ER brands | Not interchangeable with other diltiazem ER brands | Not interchangeable with other diltiazem ER brands |
| Pharmacokinetics | Significantly different from Cardizem CD | Differs from Tiazac | Differs from Tiazac and Cardizem CD |
For some patients, Tiazac might not be the most suitable option, either due to side effects or lack of efficacy. Alternatives are available and include other calcium channel blockers, beta-blockers, ACE inhibitors, or diuretics, depending on the specific condition being treated. Common alternatives include Norvasc (amlodipine), Toprol XL (metoprolol succinate), and Zestril (lisinopril). A healthcare provider can determine the best alternative based on individual health needs.
Drug Interactions
Tiazac is metabolized by the cytochrome P450 enzyme system, which means it can interact with a wide range of other medications. Key interactions include:
- Beta-blockers: Can cause additive effects on cardiac conduction, increasing the risk of abnormally slow heart rates or AV block.
- Digoxin: Can increase plasma digoxin concentrations, requiring monitoring when therapy is initiated or adjusted.
- Certain Statins: Increases the levels of some statins (e.g., simvastatin, lovastatin) in the body, which can raise the risk of muscle damage. A non-CYP3A4-metabolized statin may be preferable.
- Buspirone and Benzodiazepines: Tiazac can increase the levels of these medications, potentially leading to increased effects and side effects.
- Immunosuppressants: Tiazac can increase the levels of medications like cyclosporine and tacrolimus, necessitating careful monitoring and dosage adjustments.
- Rifampin: This antibiotic can decrease diltiazem levels, potentially reducing its effectiveness.
It is essential to inform your healthcare provider of all medications, supplements, and herbal products you are currently taking to identify potential interactions.
Conclusion
Tiazac, an extended-release formulation of diltiazem, is a valuable calcium channel blocker used to manage hypertension and chronic stable angina. Its mechanism of action involves relaxing blood vessels and reducing the heart's workload. While generally effective, it is important to be aware of potential side effects and drug interactions. Due to variations in formulations, Tiazac is not interchangeable with other diltiazem brands. Always consult with a healthcare professional to determine if Tiazac is the appropriate treatment for your condition and to ensure safe and effective use.
