Inspra (eplerenone tablets)
The following drug information is obtained from various newswires, published
medical journal articles, and medical conference presentations.
Inspra is indicated for the treatment of hypertension (high
blood pressure) and may be used alone or in combination with other
anti-hypertensive agents. Inspra is also being studied for use in
heart failure; as a selective aldosterone receptor antagonist,
Inspra may offer advantages over currently available non-selective
Inspra for oral administration contains 25 mg, 50 mg, or 100 mg
of eplerenone. The recommended starting dose of Inspra is 50 mg
administered once daily. The full therapeutic effect of Inspra is
apparent within 4 weeks.
Inspra was demonstrated to be effective in lowering high blood
pressure in over 3,000 patients and was generally well tolerated.
Patients treated with Inspra 50 to 200 mg daily experienced
significant decreases in sitting systolic and diastolic blood
pressure at trough with differences from placebo of 6-13 mm Hg
(systolic) and 3-7mm Hg (diastolic). These effects were confirmed
by assessments with 24-hour ambulatory blood pressure monitoring
Blood pressure lowering was apparent within 2 weeks from the
start of therapy with Inspra, with maximal antihypertensive effects
achieved within 4 weeks. Stopping Inspra following treatment for
8-24 weeks in six studies did not lead to adverse event rates in
the week following INSPRA withdrawal greater than following placebo
or active control withdrawal. Blood pressures in patients not
taking other antihypertensives rose 1 week after Inspra withdrawal
by about 6/3 mm Hg, suggesting that Inspra antihypertensive effect
was maintained through 8-24 weeks.
Adverse events associated with the use of Inspra may include
(but are not limited to) the following:
- Angina pectoris/myocardial infarction
- Increased GGT
Mechanism of Action
The hormone aldosterone is a key component within the RAAS
(renin angiotensin aldosterone system) and plays a significant role
in the body’s regulation of the cardiovascular system. Inspra works
with relative selectivity to block aldosterone
receptors.Aldosterone synthesis, which occurs in the adrenal gland,
is modulated by multiple factors, including angiotensin II and
non-RAAS mediators such as adrenocorticotropic hormone (ACTH) and
potassium. Aldosterone binds to mineralocorticoid receptors in both
epithelial (e.g., kidney) and nonepithelial (e.g., heart, blood
vessels, and brain) tissues and increases blood pressure through
induction of sodium reabsorption and possibly other mechanisms.
Eplerenone has been shown to produce sustained increases in
plasma renin and serum aldosterone, consistent with inhibition of
the negative regulatory feedback of aldosterone on renin secretion.
The resulting increased plasma renin activity and
aldosterone-circulating levels do not overcome the effect of
eplerenone on blood pressure.