March 2003
FORMULARY
ADDITIONS
Tegaserod Maleate
(ZelnormÔ)
2 mg and 6
mg tablets
Tegaserod is a serotonin
Type-4 (5-HT4) receptor partial agonist that binds with high
affinity at human 5-HT4 receptors.
It is indicated for the short-term treatment of women with irritable
bowel syndrome (IBS) whose primary bowel symptom is constipation. By activating 5-HT4 receptors in
the gastrointestinal tract, tegaserod stimulates
the peristaltic reflex and intestinal secretion, as well as inhibits visceral
sensitivity.
Tegaserod is contraindicated in those patients
with severe renal impairment, moderate or severe hepatic impairment, a
history of bowel obstruction, symptomatic gallbladder disease, suspected
sphincter of Oddi dysfunction, abdominal adhesions,
or a known hypersensitivity to the drug or any of its excipients.
Tegaserod should not be initiated in patients
who are currently experiencing or frequently experience diarrhea. Tegaserod should
be discontinued immediately in patients with new or sudden worsening of
abdominal pain. In clinical studies, 8.8% of patients receiving
tegaserod reported diarrhea as an adverse
experience compared to 3.8% of patients receiving placebo. The majority of
the tegaserod patients reporting diarrhea had a
single episode. In most cases, diarrhea occurred within the first week of
treatment. Typically, resolution occurred with continued therapy.
DRUG AND FOOD INTERACTIONS: Tegaserod should be administered
without food, either one hour before or two to three hours following a meal.
DOSAGE AND
ADMINISTRATION:
The
recommended dosage of tegaserod is 6 mg taken twice
daily orally before meals for 4 to 6 weeks.
For those patients who respond to therapy at 4-6 weeks, an additional
4-6 week course can be considered.
Aspirin/Extended-Release
Dipyridamole
(AggrenoxÔ)
25 mg/200 mg
Extended Release Capsules
Aspirin
25 mg/extended-release dipyridamole 200 mg capsules
are approved for the reduction of the risk of stroke in patients who have had
transient ischemia of the brain or completed ischemic stroke due to thrombosis.
Aggrenox is contraindicated in patients with
known hypersensitivity reactions to aspirin, nonsteroidal
anti-inflammatory agents, dipyridamole, acacia,
aluminum stearate, colloidal silicon dioxide, corn
starch, dimethicone, hydroxypropyl
methylcellulose, hydroxypropyl
methylcellulose phthalate, lactose monohydrate, methacrylic acid copolymer, microcrystalline cellulose, povidone, stearic acid,
sucrose, talc, tartaric acid, titanium dioxide, triacetin,
red iron oxide, and yellow iron oxide. It should also be avoided in patients
with the syndrome of asthma, rhinitis, and nasal
polyps and, to avoid the development of Reye’s syndrome, in children or
teenagers with viral infections. The
risk of bleeding may be increased in patients who consume three or more
alcoholic beverages every day and patients with inherited or acquired
bleeding disorders (e.g., liver disease and vitamin K deficiency).
Gastrointestinal
side effects (e.g., stomach pain, heartburn, nausea, vomiting, and GI
bleeding) may occur in patients treated with aspirin 25 mg/extended-release dipyridamole 200 mg. Patients should be monitored for the
development of ulceration and bleeding while using aspirin 25 mg/extended-release
dipyridamole 200 mg. Patients with a history of
peptic ulcer disease are at increased risk. Chest pain may be aggravated by
the use of Aggrenox
in patients with unstable angina, recent myocardial infarction, and other
forms of severe coronary artery disease.
The
dose of aspirin in aspirin 25 mg/extended-release dipyridamole
200 mg may be insufficient to prevent recurrent myocardial infarction or
angina pectoris. Aggrenox
should be used with caution in patients with hepatic insufficiency, hypotension, and renal dysfunction. Aspirin should be
avoided in patients with severe hepatic insufficiency or renal failure.
Therefore, aspirin 25 mg/extended-release dipyridamole
200 mg should be also be avoided in these patients.
Aggrenox therapy has been associated with
elevated hepatic enzymes, blood urea nitrogen, serum creatinine,
hyperkalemia, proteinuria,
and prolonged bleeding time. The most
common adverse effects associated with aspirin 25 mg/extended-release dipyridamole 200 mg therapy included headache, dyspepsia,
abdominal pain, nausea, diarrhea, and vomiting. The incidence of reactions
with this product is not significantly different from those reported with the
individual agents. No drug interaction studies have been conducted with the
aspirin 25 mg/extended-release dipyridamole 200 mg
formulation. All reported drug interactions in the product labeling are based
on those reported with aspirin or dipyridamole
therapy alone.
DRUG AND FOOD INTERACTIONS: The manufacturer's prescribing information lists no food/drug
interactions.
DOSAGE
AND ADMINISTRATION:
Aspirin 25
mg/extended-release dipyridamole 200 mg capsules
should be given orally twice daily, in the morning and evening. Each capsule
should be swallowed whole and should not be crushed or chewed. The daily dose
of aspirin contained in the Aggrenox formulation is within the ranges recommended by
the Ad Hoc Committee on Guidelines for the Management of Transient Ischemic Attacks, Stroke Council, American
Heart Association.
Dutasteride (AvodartÔ)
0.5 mg soft
gelatin capsule
Dutasteride, a synthetic 4-azasteroid compound,
is indicated for the treatment of symptomatic benign prostatic
hyperplasia (BPH) in men with an enlarged prostate
to improve symptoms, reduce the risk of acute urinary retention, and reduce
the risk of need for BPH-related surgery.
Dutasteride is contraindicated in women and
children, and should be avoided in patients with known hypersensitivity
reactions to dutasteride, other 5a-reductase inhibitors, or any component of the product
formulation (hydrous lactose, microcrystalline cellulose, pregelatinized
starch, sodium starch glycolate, hydroxypropyl cellulose LF, hydroxypropylmethyl
cellulose, titanium dioxide, magnesium stearate,
talc, docusate sodium, FD&C Blue 2 aluminum lake
and yellow iron oxide). Dutasteride is classified
as Pregnancy Category X. Fetal anomaly
may occur in male fetuses. Women who
are pregnant or may be pregnant should not handle the capsules since dutasteride is absorbed through the skin. In general, women should handle the
capsules with caution, and wash affected areas with soap and water if contact
is made with leaking capsules.
A digital rectal examination and
other evaluations for prostate cancer should be performed prior to initiating
therapy and periodically thereafter. Patients with large residual urinary
volume and/or severely diminished urinary flow are not good candidates. If therapy is started, they need to be
monitored for obstructive uropathy. Blood donations
should also be avoided during dutasteride therapy
and for at least 6 months after discontinuation. Caution is
advised in patients with hepatic dysfunction and
carcinogenesis is a risk with dutasteride
therapy.
Most adverse effects occurring during
dutasteride therapy are mild and transient. The most frequent adverse effects included
impotence (4.7%), decreased libido (3%), ejaculation disorders (1.4%), and gynecomastia/breast tenderness/breast enlargement
(1%). Most of these adverse events
occurred more frequently during the first year of therapy. The incidences of
other adverse effects (e.g., ENT infections, musculoskeletal
pain) are equal or less than placebo. The adverse effects leading to
withdrawal of dutasteride therapy are associated
with the reproductive system.
In vitro studies indicate that drugs (e.g., ritonavir, ketoconazole, verapamil, diltiazem, cimetidine, ciprofloxacin) that
inhibit the CYP3A4 isozyme may decrease the
metabolism of dutasteride and increase its serum
concentration. Caution is advised in
patients receiving concomitant potent CYP3A4 inhibitors. Amlodipine
therapy causes a small increase (7%) in clearance. No pharmacokinetic
or pharmacodynamic drug interactions have been
observed with tamsulosin, terazosin,
warfarin, digoxin, or cholestyramine.
DRUG AND FOOD INTERACTIONS: The manufacturer's
prescribing information lists no food/drug interactions.
DOSAGE AND
ADMINISTRATION:
The recommended dose of dutasteride is 0.5 mg orally once a day. The capsules should be swallowed whole and
not broken or chewed. No dosage
adjustments are currently recommended for elderly patients or patients with
renal or hepatic dysfunction.
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