A1,
A2,
B,
C1,
C2,
D,
E,
F,
G-H,
I-K,
L,
M,
N,
O,
P1,
P2,
Q-R,
S,
T,
U-V,
W-Z
Norpace Side Effects, and Drug Interactions - Disopyramide
Norpace Side Effects, and Drug Interactions - Disopyramide
SIDE EFFECTS
The adverse reactions which were reported in Norpace clinical
trials encompass observations in 1,500 patients, including 90 patients
studied for at least 4 years. The most serious adverse reactions
are hypotension and congestive heart
failure. The most common adverse reactions, which are dose
dependent, are associated with the anticholinergic
properties of the drug. These may be transitory, but may be persistent
or can be severe. Urinary retention
is the most serious anticholinergic
effect.
The following reactions were reported in 10% to 40% of
patients:
- Anticholinergic: dry mouth
(32%), urinary hesitancy
(14%), constipation (11%)
The following reactions were reported in 3% to 9% of patients:
- Anticholinergic: blurred vision, dry nose/eyes/throat
- Genitourinary: urinary
retention, urinary
frequency and urgency
- Gastrointestinal: nausea,
pain/bloating/gas
- General: dizziness,
general fatigue/muscle weakness, headache, malaise, aches/pains
The following reactions were reported in 1% to 3% of patients:
- Genitourinary: impotence
- Cardiovascular: hypotension
with or without congestive heart failure, increased congestive
heart failure
(see WARNINGS), cardiac
conduction disturbances
(see WARNINGS), edema/weight
gain, shortness of breath, syncope,
chest pain
- Gastrointestinal: anorexia,
diarrhea, vomiting
- Dermatologic: generalized rash/dermatoses, itching
- Central nervous
system: nervousness
- Other: hypokalemia,
elevated cholesterol/triglycerides
The following reactions were reported in less than 1%:
- Depression, insomnia,
dysuria, numbness/tingling,
elevated liver enzymes,
AV block, elevated BUN, elevated creatinine,
decreased hemoglobin/hematocrit
- Hypoglycemia has been reported in association
with Norpace administration (see WARNINGS).
Infrequent occurrences of reversible
cholestatic jaundice,
fever, and respiratory
difficulty have been reported in association
with disopyramide therapy, as have rare instances of thrombocytopenia,
reversible agranulocytosis,
and gynecomastia. Some cases of LE (lupus erythematosus) symptoms
have been reported; most cases occurred in patients who had been
switched to disopyramide from procainamide following the development
of LE symptoms. Rarely, acute
psychosis has been
reported following Norpace therapy,
with prompt return to normal
mental status
when therapy was stopped.
The physician should be aware of these possible reactions and should
discontinue Norpace or Norpace CR
therapy promptly if
they occur.
DRUG INTERACTIONS
If phenytoin or other
hepatic enzyme
inducers are taken concurrently with Norpace or Norpace CR, lower
plasma levels of disopyramide
may occur. Monitoring of disopyramide plasma
levels is recommended in such
concurrent use to avoid ineffective therapy. Other antiarrhythmic
drugs (eg, quinidine, procainamide, lidocaine, propranolol) have
occasionally been used concurrently with Norpace. Excessive widening
of the QRS complex and/or
prolongation of the Q-T interval
may occur in these situations (see WARNINGS).
In healthy subjects,
no significant
drug-drug interaction was observed when Norpace was coadministered
with either propranolol or diazepam. Concomitant administration
of Norpace and quinidine resulted in slight increases in plasma
disopyramide levels and slight decreases in plasma
quinidine levels. Norpace does not increase serum
digoxin levels.
Patients taking disopyramide phosphate
and erythromycin
concomitantly may develop increased serum
concentrations of disopyramide resulting in excessive widening of
the QRS complex and/or
prolongation of the Q-T interval (see WARNINGS).
Patients taking disopyramide phosphate
and hepatic enzyme
inhibitors concomitantly should be closely monitored.
Until data on possible interactions between verapamil and disopyramide
phosphate are obtained, disopyramide should not be administered
within 48 hours before or 24 hours after verapamil administration.
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