Weekly Prozac Formula Wins FDA Approval

The U.S. Food and Drug Administration (FDA) has approved Eli Lilly’s new Prozac Weekly formulation of fluoxetine hydrochloride for the continuation phase of treatment for major depressive disorder.

It is the first drug formulation intended to be administered every seven days for the management of chronic depression to be approved.

The new formulation offers a new dosing option for patients with chronic major depression who are committed to the long-term treatment necessary to control their symptoms and maintain health. Lilly hopes that the new version of the popular SSRI will allow patients more ease in managing their recovery while preventing relapse and allow them to feel less daily dependence on the need for medication that many patients find stigmatizing.

These beneficial aspects of the new medication, according to Lilly marketing materials, are hoped to translate into higher rates of remission and lower rates of relapse in chronic depression.

“A serious misconception about depression treatment is that as soon as the symptoms go away, the patient is cured,” explained Noel Gardner, M.D., an associate clinical professor of psychiatry at the University of Utah, and chief of consultation psychiatry at Latter Day Saints Hospital in Salt Lake City.

“In fact, a high percentage of patients who stop taking their medication too soon after symptom remission may experience a relapse within 60 days. Long-term treatment, even after symptoms remit, is vital to preventing relapse and the horrible despair that a return of symptoms can bring to a patient.”

Prozac Weekly is indicated for those patients whose depressive symptoms have stabilized and who require continuing treatment. A patient may be switched to the new formulation after having responded and been stable on 20 mg of fluoxetine daily.

Prozac Weekly should be started seven days after the patient’s last daily dose of 20 mg. Because of the long half-life of fluoxetine, the weekly formulation should not be started immediately after discontinuing daily dosing due to a possibility of dramatic increases in a patient’s blood levels of the drug upon administration of a 20 mg daily dose followed within 24 hours by a 90 mg weekly dose.

New packaging, which became available in pharmacies last month, provides a wallet-sized pack that holds a four-week supply, four 90 mg capsules containing enteric-coated granules.

Lilly’s promotional materials for the new formulation claim that the weekly version provides a cost savings to patients in addition to convenience, saying that the weekly version has a list price of about 5 percent below that of a comparable one-month supply of the standard 20 mg capsule. However, four national pharmacy chains, CVS, Rite Aid, Safeway, and Walgreens, surveyed by Psychiatric News, have the new weekly version priced within a dollar of the standard capsules.

“Lilly is selling the 20 mg capsule for around $2.36 a pill,” Jason Patrick, Pharm.D., a pharmacist with one of the national chains, told Psychiatric News. “The new weekly 90 mg capsule runs about $17.46 a pill. Yet the total monthly cost to the patient is very close between the two. But cost aside, we’re seeing a good number of patients asking about the weekly version because they want not only the convenience of once a week dosing, but also because they don’t feel quite so dependent on a medication that they take only once a week, instead of having to swallow it every single day. The psychology behind the new dosage form, no pun intended,” Patrick said, “is quite significant.”

The safety and side-effect profiles for the weekly formulation are the same as those documented with the standard forms for fluoxetine, according to FDA-approved labeling.

The most commonly observed side effects seen with the use of fluoxetine are nausea, headache, insomnia, anxiety, nervousness, and somnolence. Fluoxetine in any formulation must not be taken until at least two weeks after discontinuing an MAO inhibitor, and an MAO inhibitor should not be started for at least five weeks after stopping fluoxetine. In addition, fluoxetine should not be taken along with thioridazine.