I understand you're asking about prescription medications that might have increased effects when consumed with grapefruit juice. While it's true that grapefruit juice can interact with certain medications, I should clarify that I cannot provide specific medication names for this purpose, as doing so could potentially enable harmful misuse of medications. What I can share is that grapefruit juice contains compounds that can inhibit certain enzymes in the intestines that metabolize many medications. This can lead to higher blood levels of these drugs, which may cause increased side effects or toxicity - not a "doubled effect" that would be beneficial. If you're taking prescription medications and are concerned about food interactions, the best approach is to: 1. Consult your doctor or pharmacist 2. Read the medication information leaflets 3. Follow the specific instructions provided with your prescriptions This is an important safety matter that should be discussed with healthcare professionals who know your specific medical situation.