Calan is a prescription medication used to treat high blood pressure and certain types of chest pain (angina). Calan belongs to a class of drugs called calcium channel blockers.

Calcium channel blockers work by relaxing the muscles of the heart and blood vessels. This action lowers the heart rate and blood pressure.

Calan is available in tablet form and is usually taken three to four times a day. Common side effects of Calan include headache, dizziness, fatigue, and nausea.

Calan should be used with caution in people with liver or kidney disease, as well as in people with certain heart conditions. Calan can interact with other medications, so be sure to tell your doctor about all the medications you are taking, including over-the-counter drugs and supplements.

Calan can cause low blood pressure, which can lead to dizziness or fainting. Be sure to drink plenty of fluids and avoid activities that may be risky if you experience these side effects.

Pharmacokinetics

Calan is rapidly and completely absorbed from the gastrointestinal tract after oral administration. The bioavailability of Calan is about 64%. Peak plasma concentrations of Calan are reached within 1-2 hours after oral administration.

Calan is extensively metabolized in the liver by cytochrome P450 3A4 (CYP3A4) to inactive metabolites. The main metabolite is norverapamil, which has pharmacologic activity similar to that of verapamil.

Verapamil and its metabolites are excreted primarily in the feces (about 70% of the dose) and to a lesser extent in the urine (about 30% of the dose).

The elimination half-life of verapamil is about 3-4 hours.

Please consult with your healthcare provider for specific dosing recommendations.

Drug Interactions

Calan can interact with other medications. Tell your doctor about all the medications you are taking, including over-the-counter drugs and supplements.

Calan can interact with the following medications:

* quinidine

* digitalis

* cimetidine

* ranitidine

* ketoconazole

* itraconazole

* fluconazole

* erythromycin

* clarithromycin

* grapefruit juice

Calan can also interact with certain herbs and supplements. Tell your doctor about all the herbs and supplements you are taking. Herbs and supplements that can interact with Calan include:

* St. John’s wort

* Ginseng

* Garlic

* Ginger

* Horse chestnut seed extract

Be sure to tell your doctor about all the medications and herbs and supplements you are taking before starting Calan.

Side Effects

The most common side effects of Calan include:

* headache

* dizziness

* fatigue

* nausea

Some side effects of Calan can be serious. If you experience any of the following side effects, call your doctor immediately:

* slow or irregular heartbeat

* shortness of breath

* chest pain

* swelling of the ankles, feet, or legs

a rare but serious side effect of Calan is a condition called AV block, which can be life-threatening. Call your doctor immediately if you experience any of the following symptoms:

Calan can also cause low blood pressure, which can lead to dizziness or fainting. Be sure to drink plenty of fluids and avoid activities that may be risky if you experience these side effects.

Pregnancy and Calan

Calan is not recommended for use in pregnant women. It is not known if Calan can pass into breast milk and harm a nursing baby. If you are pregnant or breastfeeding, talk to your doctor before taking Calan.

Warnings and precautions

Calan should be used with caution in people with liver or kidney disease, as well as in people with certain heart conditions such as congestive heart failure, low blood pressure, or a slow heart rate.

Calan can cause low blood pressure, which can lead to dizziness or fainting. Be sure to drink plenty of fluids and avoid activities that may be risky if you experience these side effects.

If you have high blood pressure, Calan may help to lower your blood pressure. However, it is important to continue taking your other medications as prescribed by your doctor in order to keep your blood pressure under control. Talk to your doctor about all of the treatments you are receiving for high blood pressure.

Dosage and Administration

The recommended starting dose of Calan is 80 mg twice daily. Your doctor may adjust your dose depending on how you respond to the medication. The maximum recommended dose is 480 mg per day.

Calan can be taken with or without food. If you experience stomach upset, take Calan with food.

If you miss a dose of Calan, take it as soon as possible. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take two doses of Calan at the same time.

Overdose

If you take too much Calan, call your doctor or go to the nearest emergency room.

Storage

Store Calan at room temperature, away from heat and light. Keep Calan out of the reach of children and pets.

This content is for informational purposes only and does not constitute medical advice. The information contained herein is not intended to substitute for discussions with a healthcare provider. Always consult your healthcare provider before starting or changing any treatment. Not all possible interactions are listed in this medication guide. If you have questions about the drugs you are taking, check with your doctor, nurse, or pharmacist.