• Do not stop taking Isoptin without first talking to your doctor. If you stop taking Isoptin, your condition could become worse.
• Generic verapamil SR(Isoptin SR) may be divided in half but should not be crushed or chewed.
  

• Verapamil SR is in a class of drugs called calcium channel blockers. Verapamil relaxes (widens) blood vessels (veins and arteries), which makes it easier for the heart to pump and reduces its workload.
• Verapamil SR is used to treat hypertension (high blood pressure), to treat angina (chest pain), and to control some types of irregular heartbeats.
• Verapamil SR may also be used for purposes other than those listed in this medication guide.
  

Before taking verapamil, tell your doctor if you have

• kidney or liver disease
• Other diseases of the heart or blood vessels such as sick sinus syndrome, aortic stenosis, heart failure, heart block, Wolff-Parkinson-White syndrome, coronary artery disease, or low blood pressure
• muscular dystrophy.

You may not be able to take verapamil, or you may require a dosage adjustment or special monitoring during treatment if you have any of the conditions listed above.

• Verapamil
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If you experience any of the following serious side effects, stop taking verapamil and contact your doctor immediately or seek emergency medical treatment:

• an allergic reaction (difficulty breathing; closing of the throat, swelling of the lips, tongue, or face or hives),
• an unusually fast or slow heartbeat,
• shortness of breath (heart failure),
• fainting,
• abnormal behavior or psychosis,
• jaundice (yellowing of the skin or eyes),or
• swelling of the legs or ankles.

Other, less

Before taking verapamil, tell your doctor if you are taking any of the following drugs:

• cyclosporine (Sandimmune, Neoral),
• cimetidine (Tagamet, Tagamet HB),
• carbamazepine (Tegretol, Carbatrol),
• lithium (Lithobid, Eskalith, others),
• theophylline (Theo-Dur, Theochron, Theolair, Theobid, Elixophyllin, Slo-Phyllin, others),
• rifampin (Rifadin, Rimactane),
• phenobarbital (Luminal, Solfoton),
• an HMG CoA reductase inhibitor such as atorvastatin (Lipitor), lovastatin (Mevacor),
  Top | Read More on What other drugs will affect verapamil SR?