How many times per month is Zoladex (goserelin) administered?

Zoladex Dosing Frequency

Zoladex (goserelin) 3.6 mg is administered once every 28 days (approximately monthly), not multiple times per month 1.

Standard Dosing Schedule

The FDA-approved dosing for Zoladex 3.6 mg depot is:

• One injection every 28 days subcutaneously into the anterior abdominal wall 1
• While a delay of a few days is permissible, every effort should be made to adhere to the 28-day schedule 1

Alternative Formulation

For patients who prefer less frequent administration:

• Zoladex 10.8 mg depot can be given once every 12 weeks (3 months) 1
• This formulation is equivalent to three successive 3.6 mg depots 2
• Studies demonstrate non-inferiority between the 3-monthly 10.8 mg and monthly 3.6 mg formulations for hormone suppression 3, 2

Clinical Context by Indication

For prostate cancer:

• Long-term administration is intended unless clinically inappropriate 1
• Both 3.6 mg every 4 weeks and 10.8 mg every 12 weeks maintain testosterone suppression in the castrate range 4, 2

For endometriosis:

• Recommended duration is 6 months total 1
• Administered as 3.6 mg every 28 days during this period 1

For breast cancer:

• Long-term administration for hormone receptor-positive disease 1
• The 3.6 mg monthly formulation effectively suppresses ovarian function 5, 6

Important Clarification

Zoladex is never given multiple times within a single month. The question may reflect confusion about monthly versus per-month dosing—the answer is one injection per month (every 28 days), not multiple injections monthly.