Matzim LA is a brand-name prescription medication containing diltiazem hydrochloride, a calcium channel blocker used to treat high blood pressure and a type of chest pain called chronic stable angina. It comes as an extended-release tablet designed to work gradually throughout the day, taken once daily. The “LA” stands for “long-acting.”
How Matzim Works
Your blood vessels and heart muscle need calcium to contract. Matzim blocks calcium from entering the cells of your blood vessel walls and heart tissue through specific channels. With less calcium getting in, your blood vessels relax and widen, which lowers blood pressure and allows more blood to flow to the heart. This also reduces how hard your heart has to work to pump blood, which is why it helps with both hypertension and angina.
Diltiazem belongs to a subclass called non-dihydropyridine calcium channel blockers, which means it acts on both blood vessels and the heart itself. It slows electrical signals through the heart and reduces the force of each heartbeat slightly, giving it a broader effect than some other blood pressure medications that only target the vessels.
What Matzim Treats
Matzim LA is approved for two conditions. The first is hypertension. Lowering blood pressure reduces the risk of strokes and heart attacks over time. It can be prescribed on its own or alongside other blood pressure medications.
The second approved use is improving exercise tolerance in people with chronic stable angina, the type of chest pain that follows a predictable pattern and is triggered by physical activity or stress. By widening coronary arteries and reducing the heart’s workload, Matzim helps people stay active longer before chest pain sets in.
Available Strengths and Typical Dosing
Matzim LA comes in five tablet strengths: 180 mg, 240 mg, 300 mg, 360 mg, and 420 mg. For high blood pressure, most people start at 180 to 240 mg once daily, though some respond to lower doses. The dose can be increased gradually up to a maximum of 540 mg per day based on how well your blood pressure responds.
Because this is an extended-release formulation, the tablet releases diltiazem slowly over many hours. Peak levels in the blood don’t occur until roughly 11 to 12 hours after you take it. This slow, steady release is what allows once-daily dosing and helps maintain more consistent blood pressure control compared to immediate-release forms of diltiazem, which need to be taken multiple times a day.
How to Take It
Swallow the tablet whole. Do not crush, chew, or break it. The extended-release design depends on the tablet’s structure to control how fast the drug enters your system. Crushing or chewing it would release the full dose at once, which could cause a dangerous drop in blood pressure or heart rate.
You can take Matzim LA in the morning or at bedtime, depending on what your prescriber recommends. Food does not significantly change when the drug reaches its peak in your blood, so it can be taken with or without a meal.
Common Side Effects
Because diltiazem relaxes blood vessels and slows the heart, the most frequently reported side effects are related to those actions. Dizziness, headache, and a feeling of flushing or warmth are common, especially when you first start taking it or after a dose increase. Some people experience swelling in the lower legs or ankles, which happens because the widened blood vessels allow more fluid to pool in the extremities. Fatigue, nausea, and a slower-than-usual heart rate can also occur.
Most of these side effects are mild and tend to improve as your body adjusts to the medication over the first few weeks. A heart rate that drops noticeably low or persistent dizziness when standing up warrants a call to your prescriber, as the dose may need adjustment.
Important Drug Interactions
Diltiazem affects liver enzymes that process many other medications, which means it can raise or lower the blood levels of drugs you take alongside it. Several interactions are worth knowing about.
- Statins (cholesterol medications): Diltiazem can increase statin levels in the blood, raising the risk of muscle-related side effects. Your prescriber may choose a statin that’s less affected by this interaction or adjust the dose.
- Beta-blockers: Combining diltiazem with beta-blockers can slow the heart rate more than either drug alone. This combination is sometimes used intentionally but requires careful monitoring.
- Digoxin: Diltiazem can increase digoxin levels, so blood levels of digoxin typically need to be checked when starting, adjusting, or stopping Matzim.
- Cyclosporine: Blood levels of this immune-suppressing drug can rise significantly when taken with diltiazem, requiring close monitoring.
Kidney and liver function are checked periodically during long-term use, since both organs play a role in processing and clearing the drug from your body.
Who Should Not Take Matzim
Matzim is not appropriate for people with certain heart rhythm problems, particularly sick sinus syndrome or significant heart block (unless a pacemaker is in place). These conditions involve the heart’s electrical system already running too slowly, and adding a drug that further slows conduction could be dangerous. People with very low blood pressure or those who have had an allergic reaction to diltiazem should also avoid it.
Matzim vs. Other Diltiazem Brands
Diltiazem has been available for decades and comes in many formulations: immediate-release tablets, extended-release capsules (sold as Cardizem CD, Tiazac, and others), and extended-release tablets like Matzim LA. These formulations are not interchangeable because they release the drug at different rates and reach peak blood levels at different times. If your pharmacy switches you from one brand or formulation to another, your prescriber may need to recheck your blood pressure and heart rate to make sure the new version is working the same way.