Calan is a prescription medication used to treat chest pain (angina), an irregular heartbeat (arrhythmia), and high blood pressure (hypertension).
Calan SR is used to treat high blood pressure (hypertension).
These medications may be prescribed for other uses. Ask your doctor or pharmacist for more information.
Take Calan exactly as prescribed by your doctor. Follow the directions on your prescription label carefully.
The recommended dose range for Calan is 120 to 480 mg, divided into smaller doses and taken three or four times a day. Dose adjustments may be done based on your condition, severity of your condition, response to the medication, age, liver function, kidney function, and other medications you are taking.
The recommended dose range for Calan SR is 120 to 480 mg, divided into smaller doses and taken once or twice a day. Dose adjustments may be done based on your condition, severity of your condition, response to the medication, age, liver function, kidney function, and other medications you are taking.
Before taking Calan, tell your doctor about all of your medical conditions. Especially tell your doctor if you:
- have liver problems
- have heart problems
- have kidney problems
- have a condition called Duchenne’s muscular dystrophy
- have a condition called myasthenia gravis
- are pregnant or breastfeeding
Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements.
- Store Calan and Calan SR at room temperature between 59° to 77°F (15° to 25°C). Protect from light and moisture.
- Dispense in tight, light-resistant containers.
- Keep this and all medicines out of the reach of children.
Calan (generic: verapamil) is a prescription medication used to treat chest pain, an irregular heartbeat, and high blood pressure. Calan SR, the extended release form of Calan, is used to treat only high blood pressure. Calan belongs to a group of drugs called calcium channel blockers, which work by relaxing the blood vessels, making it easier for the heart to pump blood.
Calan comes in an immediate release tablet form and is taken 3 to 4 times a day, with or without food.
Calan SR comes in an extended release tablet form and is taken 1 to 2 times a day with food.
Common side effects of Calan include constipation, nausea, low blood pressure, and headache. This medication can cause dizziness. Do not drive or operate heavy machinery until you know how Calan affects you.
Calan is available as 40 mg, 80 mg, and 120 mg immediate release tablets.
Calan SR is available as 120 mg, 180 mg, and 240 mg extended release tablets.
Active ingredient: verapamil hydrochloride
Inactive ingredients:
- Calan – microcrystalline cellulose, corn starch, gelatin, hydroxypropyl cellulose, hypromellose, iron oxide colorant, lactose, magnesium stearate, polyethylene glycol, talc, and titanium dioxide
- Calan SR – alginate, carnauba wax, hypromellose, magnesium stearate, microcrystalline cellulose, polyethylene glycol, polyvinyl pyrrolidone, talc, titanium dioxide, and coloring agents: 240 mg—D&C Yellow No. 10 Lake and FD&C Blue No. 2 Lake; 120 and 180 mg—iron oxide
If you take too much Calan, call your healthcare provider or local Poison Control Center, or seek emergency medical attention right away.
Tell your doctor if you are pregnant or plan to become pregnant.
The FDA categorizes medications based on safety for use during pregnancy. Five categories – A, B, C, D, and X, are used to classify the possible risks to an unborn baby when a medication is taken during pregnancy.
Calan falls into category C. There are no well-controlled studies that have been done in pregnant women. Calan should be used during pregnancy only if the possible benefit outweighs the possible risk to the unborn baby.
Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements. Especially tell your doctor if you take:
- medications that block the enzyme CYP3A4 such as some macrolide antibiotics (clarithromycin, telithromycin), some HIV protease inhibitors (indinavir, nelfinavir, ritonavir, saquinavir), some HCV protease inhibitors (boceprevir, telaprevir), some azole antifungals (ketoconazole, itraconazole, posaconazole, voriconazole), conivaptan, delaviridine, and nefazadone
- medications that increase the activity of the enzyme CYP3A4 such as carbamazepine (Tegretol, Equetro, Carbatrol), phenobarbital, phenytoin (Dilantin), rifampin (Rifabutin), St. John’s wort, and nimodipine (Nimotop)
- medications to treat high blood pressure such as vasodilators, angiotensin-converting enzyme inhibitors (ACEIs), diuretics, beta blockers, and angiotensin receptor blockers (ARBs)
- anti-arrhythmic (irregular heartbeat) medications such as disopyramide (Norpace), fleicanide (Tambocor), and quinidine
- simvastatin (Zocor)
- atorvastatin (Lipitor)
- digoxin (Lanoxin)
- alcohol
- cimetidine (Tagamet)
- lithium
- carbamazepine (Equetro, Tegretol, Carbatrol)
- rifampin (Rifadin)
- cyclosporine (Neoral, Sandimmune, Gengraf)
- theophylline
- telithromycin (Ketek)
- clonidine (Catapres)
This is not a complete list of Calan drug interactions. Ask your doctor or pharmacist for more information.
Serious side effects have been reported with Calan including:
- congestive heart failure (CHF). Tell your healthcare provider right away if you experience any of the following symptoms of CHF:
- sudden weight gain
- worsening shortness of breath
- increased swelling of your feet, legs, or abdomen
- needing to use more pillows to go to sleep or sleeping in a recliner
- waking from sleep to catch your breath
- a cough that does not go away
- new or increasing irregularities in your heart rate
- hypotension. Hypotension, or low blood pressure, may cause you to feel faint or dizzy. Inadequate fluid intake, excessive sweating, diarrhea, or vomiting can lead to an excessive fall in blood pressure too. Lie down if you feel faint or dizzy. Call your doctor right away.
- liver problems. Your doctor may want to closely monitor liver function lab tests. Tell your healthcare provider right away if you experience any of the following symptoms of liver problems:
- a general feeling of discomfort, illness, or lack of well-being (malaise)
- fever
- right upper abdominal (stomach area) pain
- new irregular heartbeats. Tell your healthcare provider right away if you experience any of the following symptoms of an irregular heartbeat, medically known as an arrhythmia:
- fast or slow heart beat
- skipping beats
- lightheadedness or dizziness
- chest pain
- shortness of breath
- sweating
These medications can cause dizziness. Do not drive or operate heavy machinery until you know how Calan affects you.
Do not take Calan if you:
- have severe left ventricular dysfunction
- have low blood pressure (systolic pressure less than 90 mmHg) or cardiogenic shock
- have sick sinus syndrome (except in patients with a functioning artificial pacemaker)
- have second- or third-degree AV block (except in patients with a functioning artificial pacemaker)
- have atrial flutter or atrial fibrillation and an accessory bypass tract such as Wolff-Parkinson-White or Lown-Ganong-Levine syndromes
- have a known hypersensitivity to Calan, Calan SR, or its inactive ingredients
Tell your doctor if you are breastfeeding or plan to breastfeed.
This medication is excreted in human milk. Because of the potential for adverse reactions in nursing infants from Calan, nursing should be stopped while Calan is being taken.
Serious side effects have been reported with Calan. See the “Drug Precautions” section.
Common side effects of Calan include:
- constipation
- dizziness
- nausea
- low blood pressure, medically known as hypotension
- swelling, medically known as edema
- fatigue
- difficulty breathing
- a slow heart rate, medically known as bradycardia
- rash
- flushing
This is not a complete list of Calan side effects. Ask your doctor or pharmacist for more information.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
- Take Calan exactly as prescribed.
- Calan comes in an immediate release tablet form and is taken 3 to 4 times a day, with or without food.
- Calan SR comes in an extended release tablet form and is taken 1 to 2 times a day, with food. Do not chew, split, or break Calan SR tablets. Swallow tablets whole.
- If you miss a dose, take the missed dose as soon as you remember. If it is almost time for the next dose, skip the missed dose and take your next dose at the regular time. Do not take two doses of Calan at the same time.
Medications can interact with certain foods. In some cases, this may be harmful and your doctor may advise you to avoid certain foods. In the case of Calan, there are no specific foods that you must exclude from your diet when receiving this medication.