THEOPHYLLINE tablet extended release

Country: United States

Language: English

Source: NLM (National Library of Medicine)

Active ingredient:

THEOPHYLLINE ANHYDROUS (UNII: 0I55128JYK) (THEOPHYLLINE ANHYDROUS - UNII:0I55128JYK)

Available from:

Major Pharmaceuticals

INN (International Name):

THEOPHYLLINE ANHYDROUS

Composition:

THEOPHYLLINE ANHYDROUS 100 mg

Prescription type:

PRESCRIPTION DRUG

Authorization status:

Abbreviated New Drug Application

Summary of Product characteristics

THEOPHYLLINE- THEOPHYLLINE TABLET, EXTENDED RELEASE
MAJOR PHARMACEUTICALS
----------
THEOPHYLLINE EXTENDED-RELEASE TABLETS
DESCRIPTION
Theophylline is structurally classified as a methylxanthine. It occurs
as a white, odorless, crystalline
powder with a bitter taste. Anhydrous theophylline has the chemical
name 1H-Purine-2,6-dione,3,7-
dihydro-1,3-dimethyl-, and is represented by the following structural
formula:
C H N O M.W. 180.17
This product allows a 12-hour dosing interval for a majority of
patients and a 24-hour dosing interval
for selected patients (see DOSAGE AND ADMINISTRATION section for
description of appropriate
patient populations).
Each extended-release tablet for oral administration contains either
100 mg, 200 mg, 300 mg or 450 mg
of anhydrous theophylline. Tablets also contain as inactive
ingredients: hypromellose, anhydrous
lactose, magnesium stearate and povidone.
CLINICAL PHARMACOLOGY
MECHANISM OF ACTION
Theophylline has two distinct actions in the airways of patients with
reversible obstruction; smooth
muscle relaxation (i.e., bronchodilation) and suppression of the
response of the airways to stimuli (i.e.,
non-bronchodilator prophylactic effects). While the mechanisms of
action of theophylline are not
known with certainty, studies in animals suggest that
bronchodilatation is mediated by the inhibition of
two isozymes of phosphodiesterase (PDE lll and, to a lesser extent,
PDE IV) while non-bronchodilator
prophylactic actions are probably mediated through one or more
different molecular mechanisms, that
do not involve inhibition of PDE lll or antagonism of adenosine
receptors. Some of the adverse effects
associated with theophylline appear to be mediated by inhibition of
PDE lll (e.g., hypotension,
tachycardia, headache, and emesis) and adenosine receptor antagonism
(e.g., alterations in cerebral
blood flow).
Theophylline increases the force of contraction of diaphragmatic
muscles. This action appears to be
due to enhancement of calcium uptake through an adenosine-mediated
channel.
SERUM CONCEN