TRIMETHOPRIM tablet

Country: United States

Language: English

Source: NLM (National Library of Medicine)

Active ingredient:

TRIMETHOPRIM (UNII: AN164J8Y0X) (TRIMETHOPRIM - UNII:AN164J8Y0X)

Available from:

AvPAK

INN (International Name):

TRIMETHOPRIM

Composition:

TRIMETHOPRIM 100 mg

Prescription type:

PRESCRIPTION DRUG

Authorization status:

Abbreviated New Drug Application

Summary of Product characteristics

TRIMETHOPRIM - TRIMETHOPRIM TABLET
AVPAK
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TRIMETHOPRIM
TABLETS USP
RX ONLY
DESCRIPTION
Trimethoprim is a synthetic antibacterial available as 100 mg tablets
for oral administration.
Trimethoprim is 2,4-Diamino-5-(3,4,5-trimethoxybenzyl) pyrimidine. It
is a white to cream colored,
odorless, bitter compound. The structural formula is represented
below:
C
H N O
M.W. 290.32
Trimethoprim Tablets USP, 100 mg contain the following inactive
ingredients: anhydrous lactose,
colloidal silicon dioxide, magnesium stearate, sodium lauryl sulfate,
sodium starch glycolate and
stearic acid.
CLINICAL PHARMACOLOGY
Trimethoprim is rapidly absorbed following oral administration. It
exists in the blood as unbound,
protein-bound and metabolized forms. Ten to twenty percent of
trimethoprim is metabolized, primarily in
the liver; the remainder is excreted unchanged in the urine. The
principal metabolites of trimethoprim
are the 1- and 3-oxides and the 3'- and 4'-hydroxy derivatives. The
free form is considered to be the
therapeutically active form. Approximately 44% of trimethoprim is
bound to plasma proteins.
Mean peak plasma concentrations of approximately 1 mcg/mL occur 1 to 4
hours after oral
administration of a single 100 mg dose. A single 200 mg dose will
result in serum levels approximately
twice as high. The half-life of trimethoprim ranges from 8 to 10
hours. However, patients with
severely impaired renal function exhibit an increase in the half-life
of trimethoprim, which requires
either dosage regimen adjustment or not using the drug in such
patients (seeDOSAGE AND
ADMINISTRATION). During a 13-week study of trimethoprim administered
at a daily dosage of 200
mg (50 mg q.i.d.), the mean minimum steady-state concentration of the
drug was 1.1 mcg/mL. Steady-state
concentrations were achieved within 2 to 3 days of chronic
administration, and were maintained
throughout the experimental period.
Excretion of trimethoprim is primarily by the kidneys through
glomerular filtration and tubular
secretion. Urine concentrations of