April 26, 2017
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(disopyramide phosphate) Capsules

(disopyramide phosphate) Extended-Release Capsules


Norpace (disopyramide phosphate) is an anti-arrhythmic drug available for oral administration in immediate-release and controlled-release capsules containing 100 mg or 150 mg of disopyramide base, present as the phosphate. The base content of the phosphate salt is 77.6%. The structural formula of Norpace (disopyramide phosphate) is:

Norpace® (disopyramide phosphate)  Structural Formula Illustration

α-[2-(diisopropylamino) ethyl]-α-phenyl-2-pyridineacetamide phosphate

Norpace (disopyramide phosphate) is freely soluble in water, and the free base (pKa 10.4) has an aqueous solubility of 1mg/ml. The chloroform: water partition coefficient of the base is 3.1 at pH 7.2.

Norpace (disopyramide phosphate) is a racemic mixture of d- and l- isomers. This drug is not chemically related to other anti-arrhythmic drugs.

Norpace (disopyramide phosphate) CR (controlled-release) capsules are designed to afford a gradual and consistent release of disopyramide. Thus, for maintenance therapy, Nor-pace CR provides the benefit of less-frequent dosing (every 12 hours) as compared with the every-6-hour dosage schedule of immediate-release Norpace (disopyramide phosphate) capsules.

Inactive ingredients of Norpace (disopyramide phosphate) include corn starch, edible ink, FD&C Red No. 3, FD&C Yellow No. 6, gelatin, lactose, talc, and titanium dioxide; the 150-mg capsule also contains FD&C Blue No.1.

Inactive ingredients of Norpace (disopyramide phosphate) CR include corn starch, D&C Yellow No. 10, edible ink, ethylcellulose, FD&C Blue No. 1, gelatin, shellac, sucrose, talc, and titanium dioxide; the 150-mg capsule also contains FD&C Red No. 3 and FD&C Yellow No. 6.

What are the possible side effects of disopyramide (Norpace, Norpace CR)?

If you experience any of the following serious side effects, stop taking disopyramide and seek emergency medical attention:

  • an allergic reaction (difficulty breathing; closing of your throat; swelling of your lips, tongue, or face; or hives);
  • a new or a worsening irregular heartbeat pattern;
  • chest pain, chest discomfort, shortness of breath, or swelling of your legs or feet; or
  • severe dizziness.

Other, less serious side effects may be more likely to occur. Talk to your doctor if you experience

  • mild dizziness or...

Read All Potential Side Effects and See Pictures of Norpace »

What are the precautions when taking disopyramide phosphate (Norpace)?

Before taking disopyramide, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: diabetes, glaucoma, kidney disease, liver problems, myasthenia gravis, urinary problems (such as due to enlarged prostate, urinary retention).

This drug may rarely make you dizzy. Do not drive, use machinery, or do any activity that requires alertness until you are sure you can perform such activities safely. Limit alcoholic beverages.

Before having surgery, tell your doctor or dentist that you are using this...

Read All Potential Precautions of Norpace »

Last reviewed on RxList: 1/4/2017
This monograph has been modified to include the generic and brand name in many instances.

Norpace - User Reviews

Norpace User Reviews

Now you can gain knowledge and insight about a drug treatment with Patient Discussions.

Here is a collection of user reviews for the medication Norpace sorted by most helpful. Patient Discussions FAQs

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