Can I cut a neurontin 300 mg capsule in half, and just take half of it?

A good rule of thumb to follow is if it is not scored, dont try to break it in half! That works most of the time but not always. Capsules should never be broken however.

No. Medications are developed to provide relief or resolution of a condition. Part of that formulation is designed to to be absorbed ratably by your body. By breaking a capsule, you may be altering the absorption rate as well as how and where the medication is dissolved in your body. Check with your pharmacist, the drug company's website, or the PDR online.