Calan

You should tell your doctor about all prescription, non-prescription, illegal, recreational, herbal, nutritional, or dietary drugs you are taking, especially:

• St. John's wort
• Alpha blockers such as prazosin (Minipress)
• Antifungals such as itraconazole (Sporanox) and ketoconazole (Nizoral)
• Aspirin
• Beta blockers such as atenolol (Tenormin), metoprolol (Lopressor, Toprol XL), nadolol (Corgard), propranolol (Inderal), and timolol (Betimol, Istalol, Timoptic, in Cosopt)
• Carbamazepine (Tegretol)
• Cimetidine (Tagamet)
• Clarithromycin (Biaxin, Prevpac)
• Cyclosporine (Neoral, Sandimmune)
• Digoxin (Lanoxin, Lanoxicaps)
• Disopyramide (Norpace)
• Erythromycin (E.E.S., E-Mycin, Erythrocin)
• Flecainide (Tambocor)
• Certain HIV protease inhibitors such as indinavir (Crixivan), nelfinavir (Viracept), and ritonavir (Norvir, Kaletra)
• Quinidine (Quinaglute, Quinidex)
• Lithium (Eskalith, Lithobid)
• Medications to treat high blood pressure
• Nefazodone (Dutonin)
• Phenobarbital
• Rifampin (Rifadin, Rimactane)
• Telithromycin (Ketek)
• Theophylline (Theolair, Uniphyl)

Other Verapamil Interactions

Verapamil may change how your body responds to alcohol, causing effects to be more severe and long-lasting.

You should also talk to your doctor about consuming grapefruit or grapefruit juice while taking this drug.

For Angina:

Immediate release formulations: Initially 80-120 milligrams (mg), three to four times a day. It can be increased up to 480 mg per day, in divided doses.

Extended-release formulations: Initially 180 mg once daily at bedtime. It can be increased up to - 540 mg at bedtime.

For Hypertension:

Immediate release formulations: Initially 80 mg three times a day. It can be increased up to 480 mg per day, given in divided doses, although doses greater than 360 mg offer no additional benefit.

Extended-release formulations: Initially 180-240 mg once daily. It can be increased to 240 mg, twice daily.

For Migraine:

Immediate release formulations: Initially 80 mg three times daily. Higher doses have also been used.

Verapamil Overdose

If you suspect an overdose, contact a poison control center or emergency room immediately.

You can get in touch with a poison control center at (800) 222-1222.

Missed Dose of Verapamil

If you miss a dose of verapamil, take it as soon as you remember.

However, if it is almost time for your next dose, skip the missed dose and continue on your regular schedule.

Do not "double up" to make up for a missed one.

CALAN (verapamil HCl) is a calcium ion influx inhibitor (slow-channel blocker or calcium ion antagonist) available for oral administration in film-coated tablets containing 40 mg, 80 mg, or 120 mg of verapamil hydrochloride.

The structural formula of verapamil HCl is:

C27H38N2O4 · HCl     M.W. = 491.08

Benzeneacetonitrile, α-[3-[[2-(3,4-dimethoxyphenyl)ethyl] methylamino]propyl]-3,4dimethoxy-α-(1-methylethyl) hydrochloride

Verapamil HCl is an almost white, crystalline powder, practically free of odor, with a bitter taste. It is soluble in water, chloroform, and methanol. Verapamil HCl is not chemically related to other cardioactive drugs.

Inactive ingredients include microcrystalline cellulose, corn starch, gelatin, hydroxypropyl cellulose, hypromellose, iron oxide colorant, lactose, magnesium stearate, polyethylene glycol, talc, and titanium dioxide.

Calan is part of the drug class:

• Phenylalkylamines

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.

Verapamil falls into category C. There are no well-controlled studies that have been done in pregnant women. Verapamil should be used during pregnancy only if the possible benefit outweighs the possible risk to the unborn baby.

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 verapamil, nursing should be stopped while verapamil is being taken.

Take verapamil exactly as prescribed by your doctor. Follow the directions on your prescription label carefully.

Oral:

• The recommended dose range for immediate-release tablets is 40 to 480 mg, divided into smaller doses and taken three or four times a day.
• The recommended dose range for verapamil extended- and sustained-release forms 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.

Injectable:

• This medication is available in an injectable form to be dosed by a healthcare professional.

Verapamil may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert.

Avoid getting up too fast from a sitting or lying position, or you may feel dizzy. Get up slowly and steady yourself to prevent a fall.

Drinking alcohol can further lower your blood pressure and may increase certain side effects of verapamil.

Grapefruit and grapefruit juice may interact with verapamil and lead to potentially dangerous effects. Discuss the use of grapefruit products with your doctor.

Get emergency medical help if you have signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

• chest pain, fast or slow heart rate;

• a light-headed feeling, like you might pass out;

• shortness of breath (even with mild exertion), swelling, rapid weight gain;

• lung problems--anxiety, sweating, pale skin, wheezing, gasping for breath, cough with foamy mucus; or

• liver problems--loss of appetite, upper stomach pain, tiredness, easy bruising or bleeding, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes).

Common side effects may include:

• constipation;

• headache, dizziness; or

• abnormal liver function tests.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

In chronic animal toxicology studies, verapamil caused lenticular and/or suture line changes at 30 mg/kg/day or greater, and frank cataracts at 62.5 mg/kg/day or greater in the beagle dog but not in the rat. Development of cataracts due to verapamil has not been reported in man.

Summary of Use during Lactation

Limited information indicates that maternal doses of verapamil up to 360 mg daily produce low levels in milk and newborns may have detectable verapamil serum levels, but levels are low. Verapamil would not be expected to cause any adverse effects in breastfed infants, especially if the infant is older than 2 months.

Drug Levels

Maternal Levels. The first 2 cases of verapamil excretion in milk found disparate results.[1][2] In one, milk levels ranging from 19 to 38 mcg/L were found at various times during a dosing regimen of 80 mg orally 3 times daily in a mother who was 3 to 5 days postpartum. Milk levels averaged 23% of serum levels.[2] In the second woman who was 13 days postpartum, milk levels peaked at about 300 mcg/L about 1 hour after each 80 mg dose in a 80 mg 4 times daily regimen and were approximately equal to serum levels at most times.[1]

In 2 later cases (below), plasma and milk verapamil and norverapamil levels were measured using more accurate methods. The results reported in these 2 papers were consistent with each other and differed from both of the earlier studies in some aspects.[3][4]

A woman who was 8 weeks postpartum and taking 120 mg of verapamil orally every 8 hours had milk verapamil levels of 113 and 154 mcg/L of verapamil just before a dose, with the higher level occurring later in the feeding, probably because of the higher fat content. At 4 hours after a dose, levels were 133 and 205 mcg/L early and late in the feeding, respectively. Norverapamil levels were similar early and late in each feeding and averaged 50 mcg/L before the dose and 58 mcg/L at 4 hours. The authors estimated that a nursing infant would receive less than 0.5% of the mother's weight-adjusted dosage.[3]

A 3-month-postpartum woman taking verapamil 80 mg orally three times daily had peak milk levels of verapamil of 79 mcg/L 1 hour after the dose and norverapamil of 22 mcg/L 2 hours after the dose. The authors estimated that a nursing infant would receive less than 0.01% of the mother's weight-adjusted dose daily.[4]

Infant Levels. A serum level of 2.1 mcg/L was reported in a 5-day-old infant whose mother was taking 80 mg of verapamil orally 3 times daily. It is possible that some of the drug in the infant's serum derived from transplacental passage, although the mother received no verapamil on the day of delivery.[2]

Two older infants (8 weeks and 3 months) had no detectable serum verapamil or norverapamil (<1 mcg/L) with oral maternal doses of 80 and 120 mg 3 times daily.[3][4]

Effects in Breastfed Infants

No adverse reactions have been reported among 3 infants aged 13 days, 8 weeks and 3 months who were exposed to verapamil in breastmilk.[2][3][4]

Effects on Lactation and Breastmilk

Verapamil can cause hyperprolactinemia and galactorrhea.[5][6] The clinical relevance of these findings in nursing mothers is not known. The maternal prolactin level in a mother with established lactation may not affect her ability to breastfeed.

Alternate Drugs to Consider

(Calcium Channel Blockers) Diltiazem, Nifedipine, (Hypertension) Enalapril, Hydrochlorothiazide, Methyldopa, Propranolol

References

1. Inoue H, Unno N, Ou M-C et al. Level of verapamil in human milk. Eur J Clin Pharmacol. 1984;26:657-8. PMID: 6468488

2. Andersen HJ. Excretion of verapamil in human milk. Eur J Clin Pharmacol. 1983;25:279-80. Letter. PMID: 6628513

3. Miller MR, Withers R, Bhamra R et al. Verapamil and breast-feeding. Eur J Clin Pharmacol. 1986;30:125-6. PMID: 3709626

4. Anderson P, Bondesson U, Mattiasson I et al. Verapamil and norverapamil in plasma and breast milk during breast feeding. Eur J Clin Pharmacol. 1987;31:625-7. PMID: 3830249

5. Gluskin LE, Strasberg B, Shah JH. Verapamil-induced hyperprolactinemia and galactorrhea. Ann Intern Med. 1981;95:66-7. PMID: 7195677

6. Fearrington EL, Rand CH Jr, Rose JD. Hyperprolactinemia-galactorrhea induced by verapamil. Am J Cardiol. 1983;51:1466-7. PMID: 6682619