TL;DR:
- Cardizem is the brand name for diltiazem, a calcium‑channel blocker used mainly for high blood pressure and certain heart rhythm problems.
- Typical oral doses range from 30mg to 360mg per day, depending on the condition and formulation.
- Common side effects include dizziness, headache, swelling, and constipation; serious risks involve low heart rate, low blood pressure, and liver issues.
- Always inform your doctor about other meds, especially beta‑blockers, statins, or anti‑arrhythmics, to avoid dangerous interactions.
- Regular monitoring of blood pressure, heart rate, and liver function helps keep treatment safe and effective.
What is Cardizem and How Does It Work?
Cardizem is the trade name for the drug diltiazem, which belongs to a class called calcium‑channel blockers (CCBs). In simple terms, CCBs relax the muscles of your heart and blood vessels by stopping calcium from entering the cells. Calcium is what makes muscles contract, so limiting its entry reduces the force of the heartbeat and widens the arteries.
Because of this dual action, Cardizem is commonly prescribed for two main reasons:
- Hypertension (high blood pressure): By relaxing the arterial walls, it lowers the pressure the heart has to pump against.
- Angina and certain arrhythmias: It eases the heart’s workload and helps restore a regular rhythm, especially in conditions like atrial fibrillation or supraventricular tachycardia.
There are three primary formulations on the market:
- Immediate‑release (IR) tablets - 30mg, 60mg, 120mg.
- Extended‑release (ER) capsules - 120mg, 180mg, 240mg, 300mg.
- Injectable form - used only in hospitals for acute rate control.
Each version is designed to give a slightly different release pattern, so your doctor will pick the one that matches your condition, lifestyle, and how your body reacts.
How to Take Cardizem: Dosage, Timing, and Practical Tips
Getting the dose right is crucial. Below is a quick rundown of typical starting points, but remember that doctors tailor the regimen to you.
Typical oral dosing
- Hypertension: Start with 30mg IR once daily; many patients move to 60mg IR twice daily or an ER capsule of 120mg once daily.
- Angina: 60mg IR three times a day, or 120‑240mg ER once daily, depending on severity.
- Rate control for atrial fibrillation: 60‑120mg IR twice daily, or 180‑240mg ER once daily.
Doctors often begin low and increase slowly to avoid sudden drops in blood pressure or heart rate.
Taking the medication
- Swallow ER capsules whole - do not crush or chew, as this can release the drug too quickly.
- IR tablets can be taken with or without food, but a light snack helps reduce stomach upset.
- Take it at the same time each day to keep blood levels stable.
- If you miss a dose, take it as soon as you remember unless it’s almost time for the next dose - then skip the missed one. Never double up.
Monitoring while on Cardizem
Regular check‑ins with your healthcare provider are a must. Expect these at the start and after any dose change:
- Blood pressure measurement - aim for <120/80mmHg, but your doctor will set a target based on your overall risk.
- Heart rate - a resting rate below 60bpm may be a sign to lower the dose.
- Liver function tests - diltiazem is processed by the liver, so abnormal enzymes signal a need to adjust.
- Electrolyte panel - especially potassium and magnesium, which affect heart rhythm.
Having a home blood pressure cuff and a simple heart‑rate monitor can make these visits smoother.
Common pitfalls to avoid
- Stopping abruptly can cause rebound hypertension. Taper under doctor guidance.
- Mixing with grapefruit juice - it can increase diltiazem levels and raise the risk of side effects.
- Skipping meals if you’re prone to dizziness - low blood sugar plus low blood pressure can make you feel faint.
Safety Profile: Side Effects, Interactions, and When to Call the Doctor
Every medication has a trade‑off. Knowing what to expect helps you stay ahead.
Typical side effects (1‑2weeks in)
- Dizziness or light‑headedness - especially when standing up quickly.
- Headache - often mild and fades as your body adjusts.
- Swelling of ankles or feet - due to fluid retention.
- Flushing, feeling warm, or a mild rash.
- Constipation - more common with higher doses.
Most of these settle within a few weeks. If they persist or worsen, let your prescriber know.
Serious but rare adverse events
- Bradycardia (heart rate <50bpm) - can cause fatigue, fainting, or chest discomfort.
- Severe hypotension - may lead to dizziness, blurred vision, or shock in extreme cases.
- Heart block - a conduction problem that shows up on an ECG.
- Elevated liver enzymes - can signal liver stress.
- Life‑threatening allergic reaction - swelling of lips, tongue, or throat, and difficulty breathing.
If you notice any of these, seek medical help right away.
Key drug interactions
Cardizem shares the metabolic pathway CYP3A4, so anything that messes with that enzyme can change its blood levels.
- Beta‑blockers (e.g., metoprolol): The combo can push heart rate too low.
- Statins metabolized by CYP3A4 (e.g., simvastatin, lovastatin): Increased risk of muscle toxicity.
- Antifungals (ketoconazole, itraconazole) and certain antibiotics (clarithromycin): Raise diltiazem concentration, upping side‑effect risk.
- Anti‑arrhythmics (e.g., amiodarone, quinidine): May cause dangerous slowing of the heart.
- Other CCBs (verapamil, amlodipine): Usually unnecessary and can lead to additive blood‑pressure drop.
Always hand your pharmacist a complete medication list, including over‑the‑counter drugs and supplements.
Contraindications - who should avoid Cardizem?
- Severe hypotension (systolic <90mmHg).
- Second‑ or third‑degree heart block without a pacemaker.
- Acute myocardial infarction (unless specifically ordered).
- Pregnancy - only if the benefit outweighs risk; most doctors prefer alternatives.
- Liver failure - drug clearance is impaired.
Frequently asked questions
- Can I drink alcohol while on Cardizem? Moderate alcohol is generally okay, but both can lower blood pressure, so drink cautiously.
- Is Cardizem safe for older adults? Yes, but start at the lowest dose and monitor kidney and liver function closely.
- Do I need to take Cardizem forever? Hypertension often requires long‑term therapy, but dose adjustments are common. Some patients taper off after lifestyle changes and blood‑pressure control.
- What should I do if I feel a rapid heartbeat? Pause the dose and call your doctor; it could be a sign of an interaction or a need for dose reduction.
- Can I switch from another calcium‑channel blocker to Cardizem? A physician can cross‑taper; don’t switch on your own.
Next steps for safe use
1. Set up a medication calendar - whether a phone reminder or a pill organizer, consistency matters.
2. Keep a log of blood‑pressure readings and any side‑effects. Bring this to every appointment.
3. Review your full medication list with your doctor at least annually.
4. If you’re planning surgery or any procedure, inform the team that you’re on Cardizem; it may need to be held temporarily.
Following these practices helps you get the benefits of Cardizem while keeping risks low.