SILVER SPRING, MD. – Intravenous phenylephrine, used widely for decades to increase blood pressure in patients who become hypotensive during anesthesia, in intensive care, and in other situations, should be approved for use to increase blood pressure in patients who become hypotensive during neuraxial anesthesia, a Food and Drug Administration advisory panel unanimously agreed at a meeting on Sept. 13.
However, at the meeting the Cardiovascular and Renal Drugs Advisory Committee voted 8 to 2 against recommending approval of IV phenylephrine as a treatment to increase blood pressure in acute hypotensive states, such as shock, because more studies are needed.
IV phenylephrine, a selective alpha1-adrenergic receptor agonist, has been used for decades without being approved by the FDA, since it was available before the current drug approval process was established, and is one of the unapproved products that the FDA considers medically necessary.
As a result of the FDA’s Unapproved Drugs Initiative, West-Ward Pharmaceuticals submitted an application for approval of intravenous phenylephrine "to increase blood pressure in acute hypotensive states, such as shock and perioperative hypotension." The application included 50 published studies, mostly of low-risk women who had neuraxial anesthesia during cesarean delivery.
At the meeting, company officials and clinicians who spoke on behalf of the company summarized the results of these studies, published from the 1980s through 2010.
Only eight studies were in patients with sepsis or septic shock, so the benefits and risks of IV phenylephrine for this use were limited, and there were no studies on the use of IV phenylephrine as a treatment for other types of shock, according to the FDA.
For indications other than neuraxial anesthesia, more data are needed before approval, including more data on efficacy and the impact of treatment on end-organ damage, said panel chair Dr. A. Michael Lincoff, professor of medicine at the Cleveland Clinic.
One of the two panelists voting in favor of approval for the full indication (including acute hypotensive episodes due to shock), Dr. Joseph Tobin, professor of anesthesiology and pediatrics at Wake Forest Baptist Health, Winston-Salem, N.C., said that he felt comfortable after 30 years of use with this drug for the full indication, as proposed by the company.
The FDA usually follows the recommendations of its advisory panels. Panel members had no conflicts to disclose.