Diltiazem – Dose, ROA, MOA, PK, PD, Indications & More

  1. Dose and Dosage: The dose of diltiazem can vary depending on the condition being treated, patient’s age, and other factors. It’s typically taken orally, and the dosage ranges from 30 mg to 360 mg per day, divided into multiple doses or taken as a single dose. Your doctor will determine the appropriate dosage for your specific condition.
  2. Frequency: Diltiazem is usually taken two to four times daily, depending on the formulation and the condition being treated. It’s important to follow your doctor’s instructions regarding the frequency of dosing.
  3. Route of Administration (ROA): Diltiazem is available in various forms, including tablets, extended-release capsules, and intravenous (IV) formulations. The route of administration depends on the specific formulation prescribed by your doctor.
  4. Mechanism of Action (MOA): Diltiazem belongs to a class of medications called calcium channel blockers. It works by relaxing blood vessels and reducing the workload on the heart, which helps to lower blood pressure and improve blood flow to the heart.
  5. Pharmacokinetics (PK): After oral administration, diltiazem is well absorbed from the gastrointestinal tract. It undergoes extensive metabolism in the liver, and its elimination half-life ranges from 3 to 12 hours, depending on the formulation.
  6. Pharmacodynamics (PD): Diltiazem inhibits the influx of calcium ions into smooth muscle cells in blood vessels and the heart, leading to relaxation of vascular smooth muscle and decreased cardiac contractility.
  7. Pathophysiology: Diltiazem is used to treat various cardiovascular conditions, including hypertension (high blood pressure), angina (chest pain), and certain types of arrhythmias (irregular heart rhythms).
  8. Indications: Diltiazem is indicated for the management of hypertension, chronic stable angina, variant angina, and certain types of supraventricular tachycardias, such as atrial fibrillation or atrial flutter.
  9. Contraindications: Diltiazem should not be used in patients with acute myocardial infarction, severe hypotension, sick sinus syndrome, or second- or third-degree atrioventricular block without a pacemaker, among other contraindications. It’s important to discuss any medical conditions or medications you’re taking with your doctor before starting diltiazem.
  10. Drug Interactions: Diltiazem can interact with several medications, including beta-blockers, digoxin, statins, and certain antiarrhythmic drugs. It’s important to inform your doctor about all the medications you’re taking, including prescription, over-the-counter, and herbal supplements, to avoid potential interactions.
  11. Precautions: Diltiazem should be used with caution in patients with liver or kidney disease, heart failure, or certain types of arrhythmias. Your doctor may need to adjust your dosage or monitor you closely for any adverse effects.
  12. Monitoring and Laboratory Tests: Regular monitoring of blood pressure, heart rate, and liver function may be recommended while taking diltiazem. Your doctor may also perform electrocardiograms (ECGs) to monitor heart rhythm.

As always, it’s important to follow your doctor’s instructions and report any concerns or side effects while taking diltiazem.


  1. Purpose: Diltiazem is primarily used to treat various cardiovascular conditions, including hypertension (high blood pressure), chronic stable angina (chest pain), variant angina, and certain types of arrhythmias (irregular heart rhythms), such as atrial fibrillation or atrial flutter.
  2. Usage: Diltiazem is typically taken orally as directed by your doctor, usually with or without food. It’s important to follow the prescribed dosage and frequency as instructed. Do not crush, chew, or break extended-release tablets; swallow them whole.
  3. Other Uses: Sometimes, diltiazem may be prescribed for off-label uses, such as migraine prevention, Raynaud’s phenomenon, or certain types of esophageal spasms. However, these uses should only be undertaken under the supervision of a healthcare provider.
  4. Precautions: You should avoid consuming grapefruit or grapefruit juice while taking diltiazem, as it can increase the levels of diltiazem in your bloodstream and potentially lead to adverse effects. Also, inform your doctor about any other medications, supplements, or herbal products you are taking to avoid interactions.
  5. Dietary Changes: In general, no specific dietary restrictions are required while taking diltiazem. However, maintaining a healthy diet low in sodium and saturated fats can complement the treatment of hypertension and heart conditions.
  6. Missed Dose: If you forget to take a dose, take it as soon as you remember. However, if it’s almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not double the dose to catch up.
  7. Side Effects: Common side effects of diltiazem may include dizziness, headache, flushing, nausea, and constipation. More serious side effects may include slow heart rate, fainting, swelling of the ankles or feet, and signs of liver problems. Contact your doctor if you experience any concerning side effects.
  8. Storage and Disposal: Store diltiazem at room temperature away from light and moisture. Keep it out of reach of children and pets. Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed.
  9. Emergency Situations: In case of an overdose, contact your local poison control center or emergency room immediately. Symptoms of overdose may include severe dizziness, fainting, or irregular heartbeats. If you experience any severe symptoms or have concerns about your health, seek medical attention promptly.