The Approach to Repurposed Drugs for Cancer
Repurposed drugs are showing real results in cancer care. Learn practical strategies and dosing from Dr. Paul Marik and Dr. Justus Hope in this free guide.
“You have cancer.”
Nobody is ever truly ready to hear those words. In the days that follow, most patients are quickly swept into a program of chemotherapy, radiation, and surgery. It’s an incredibly scary track to be on—and far too often, it feels like you’re on it alone.
But there’s something important every cancer patient should know: you are not limited to just one set of tools. More and more patients are finding hope—and better outcomes—by working with integrative and adjunctive care doctors who combine conventional treatments with safe, science-backed therapies. This collaborative approach not only addresses the cancer itself, but also supports the whole person through the journey.
That’s exactly why Dr. Paul Marik teamed up with Dr. Justus Hope to create one of the most critical cancer treatment guides available on the planet: Approach to Repurposed Drugs in Patients with Cancer. Backed by decades of clinical experience and the latest science, it’s a lifeline for patients and a trusted roadmap for clinicians who want more than the status quo.
Download PDF: Approach to Repurposed Drugs for Cancer (an up-to-date version can always be found on our website).
🎗️ Support Independent Cancer Research
“Conventional cancer treatments have fallen short for too many. It’s time to evaluate innovative, less toxic therapies that can redefine what’s possible for patients and their families.” — Dr. Paul Marik
For just a few short weeks, IMA is running a special match campaign: thanks to three generous donors, every donation will be doubled. Help us turn $250,000 into $500,000—and fund the cancer care patients actually need.
💡 Why We Made This Guide
Cancer Care, the monograph by Dr. Paul Marik, is a huge and valuable resource. It pulls together an extraordinary amount of research, including dosage guidance for dozens of repurposed compounds. But because the cancer treatment landscape is always shifting, there was a need for something more agile—something we could update regularly as new information comes to light.
That’s what this guide is: a streamlined companion to Cancer Care. It has already been updated several times and will continue to evolve, making it a true living document. It was designed with both patients and doctors in mind, and it’s best used when those two parties are working together to shape a care plan. This is also one of several companion guides, all of which can be found at our main Cancer Care page.
As Dr. Marik explains:
“We provide the clinician but also the patient with an overall guide to how to manage these patients.”
📖 What’s Inside the Guide
Two practical tracks for care — a Limited and an Aggressive approach — with core agents and dosing ranges to help you and your clinician choose a starting point.
Evidence-informed rankings of repurposed compounds, showing which ones block key cancer stem cell (CSC) pathways and how they stack up on safety.
Cancer-specific protocols for common tumor types (e.g., prostate, breast, colorectal, lung, melanoma, ovarian, endometrial, liver, head & neck, pancreatic, gastric, glioblastoma) plus blood cancers (lymphoma, multiple myeloma, pediatric AML).
Stage-based guidance for both carcinoma in situ (stage 0) and stage 4 metastatic disease.
Cautions & interactions you should know (e.g., curcumin with blood thinners, EGCG dose thresholds, zinc nuance in prostate cancer, metformin with berberine).
🎯 Limited vs. Aggressive Approach
For best results, cancer care must be individualized. To make that practical, this guide offers two starting frameworks can be adjusted over time:
Limited Approach (fewer agents, lower doses, easier to layer alongside conventional therapy) and;
Aggressive Approach (more agents up front for metastatic or highly aggressive disease, then taper if response is good).
The goal in both is to block multiple cancer stem cell (CSC) pathways while matching intensity to the clinical picture.
The following protocols are drawn directly from Approach to Repurposed Drugs in Patients with Cancer. They are current as of August 2025, but because this guide is updated regularly, you should always check above for the most recent PDF version.
Limited Therapy Approach
Low carbohydrate, Low Glycemic diet
Include broccoli sprouts 2–3x per week (sulforaphane)
Brewed green tea (<4 cups/day)
Ivermectin
0.2–0.4 mg/kg/day (commonly 0.3 mg/kg/day)
Doxycycline
50 mg daily with 2 g oral vitamin C
Consider cycling after 6 months
Vitamin D + K2
Vitamin D 10,000 U daily + Vitamin K2 100 µg daily
Monitor 25-OH Vit D and PTH levels
Curcumin extract
Twice daily (high bioavailability)
Start 2–4 g/day, titrate up to 8 g/day
Melatonin
20 mg at night (titrate up from 5 mg)
Propranolol
10–40 mg twice daily as tolerated
Resveratrol
500 mg twice daily (high bioavailability)
Green tea extract (EGCG)
Twice daily (<800 mg/day)
Aggressive Therapy Approach
Low Glycemic “ketogenic” diet
Ivermectin
0.4–0.8 mg/kg/day (commonly 0.6 mg/kg/day)
Increase up to 1 mg/kg/day if response is poor
Mebendazole
200 mg daily
Doxycycline
50 mg daily with 2 g oral vitamin C
Consider cycling after 6 months
Vitamin D + K2
Vitamin D 10,000 U daily + Vitamin K2 100 µg daily
Monitor 25-OH Vit D & PTH
Titrate per Coimbra Protocol
Curcumin extract
Twice daily (high bioavailability)
Metformin
500–1000 mg twice daily
Green tea extract (EGCG)
Twice daily (<800 mg/day)
Propranolol
10–40 mg twice daily as tolerated
Melatonin
20 mg at night (titrate up from 5 mg)
Resveratrol
500 mg twice daily (high bioavailability)
Modified Citrus Pectin
14.4 g/day (6 tablets, three times a day)
Sulforaphane
Free stabilized extract from broccoli seeds; dosage varies
Omega-3 fatty acids
2–4 g/day
Atorvastatin or Simvastatin
40–80 mg daily or simvastatin 40 mg daily
Avoid long-term use or precipitous LDL reduction due to dementia risk
Propranolol (again)
20–40 mg twice daily (dose range adjustment)
Quercetin
500–1000 mg twice daily
Top 10 Compounds for Cancer Stem Cell (CSC) Blocking Activity
As mentioned above, the goal of using these cancer treating compounds is to target cancer stem cell pathways. Using AI tools, Dr. Marik and Dr. Hope aimed to evaluate both the effectiveness and the safety of the compounds on their list. As you’ll see from the image below, there are a number of safe compounds with evidence to show they work too.
🛠️ Tailoring Repurposed Therapy to Cancer Type
Every patient responds differently, and cancers themselves can behave in unique ways. That’s why this guide doesn’t stop at general strategies—it also highlights cancer-specific approaches so treatment can be better matched to each diagnosis.
The goal remains the same: to block multiple cancer stem cell (CSC) pathways while balancing safety and adaptability. But the details matter, and they shift depending on tumor type, stage, and clinical picture.
Cancers Covered in This Guide
Prostate
Breast
Colorectal
Lung — Small Cell (SCLC)
Lung — Non-Small Cell (NSCLC)
Melanoma
Ovarian
Endometrial (uterine)
Liver (hepatocellular carcinoma)
Head & Neck squamous cell carcinoma
Pancreatic*
Gastric*
Glioblastoma*
Lymphoma
Multiple Myeloma
Acute Myeloid Leukemia (pediatric)
Esophageal*
Sarcomas*
⚠️ Special Considerations
It’s worth highlighting that a few cancer types require special attention within this framework. While the principles of repurposed therapy apply broadly, these cancers carry unique challenges and warrant extra consideration:
* Pancreatic Cancer
Pancreatic cancers often have significantly poorer outcomes compared to most other cancers. Metastases to the liver and lungs are common, and median survival for advanced disease remains limited. Many repurposed drugs show little direct activity against pancreatic cancer cells, though certain agents adapted from the Bigelsen Treatment Protocol may provide targeted benefit.
* Gastric Cancer
The prognosis for gastric cancer varies widely depending on stage and patient factors. While localized disease may carry a relatively favorable survival rate, outcomes drop sharply once the cancer becomes regional or metastatic. This variability underscores the importance of tailoring repurposed drug strategies to individual disease stage and context.
* Glioblastoma (GBM)
Glioblastoma remains one of the most aggressive and treatment-resistant cancers, with survival often measured in months. Repurposed drugs may help by targeting resistant cancer stem cells and working synergistically with conventional therapies. Treatment must also account for the blood–brain barrier and the tumor’s strong immunosuppressive environment. Current evidence suggests the best results come when repurposed agents are layered on top of standard therapy, and while certain combination strategies (e.g., modified citrus pectin + PD-1 inhibitors + ivermectin) look promising, robust clinical validation is still lacking.
* Esophageal Squamous Cell Carcinoma (ESCC)
ESCC is highly lethal, and new approaches are urgently needed. Several repurposed drugs appear especially relevant—including azithromycin (weekly, limited course), curcumin, EGCG, vitamin D, quercetin, ivermectin, mebendazole, metformin, resveratrol, and atorvastatin. These agents may offer synergistic benefit alongside conventional treatment and deserve close attention in collaborative patient-clinician decision-making.
* Sarcomas
Sarcomas are rare but often highly aggressive cancers, frequently diagnosed late. Their metabolism is dominated by the Warburg effect, making metabolic interventions attractive. Repurposed agents such as propranolol (especially in angiosarcoma), EGCG, curcumin, vitamin D, mebendazole, and high-dose IV vitamin C are highlighted as potential adjuncts. Because of their biology, sarcomas are a strong case for integrating repurposed therapies with conventional treatment from the outset.
⚠️ Cautions & Contraindications
While repurposed drugs and natural compounds can play a powerful role in cancer care, several require special care and monitoring. Always discuss these with your physician before starting or adjusting therapy.
Curcumin – May increase bleeding risk. Stop prior to surgery. Added cautions with anticoagulants, antiplatelets, or NSAIDs.
Doxycycline – Minimal impact on the microbiome, but long-term use should still be considered carefully.
Green Tea Extract (EGCG) – Risk of hepatotoxicity. Keep total intake below 800 mg/day, ramp slowly, and take with food (± vitamin C). Avoid in liver disease. Do not combine curcumin with piperine due to added liver risk. Monitor LFTs.
Metformin + Berberine – Combination may cause hypoglycemia. Monitor closely or reduce one of the agents.
Zinc (in Prostate Cancer) – Low doses may be helpful in early non-metastatic disease, but avoid high-dose or long-term use, as this may increase risk and aggressiveness.
🌅The Future of Cancer Treatment
Repurposed drugs hold enormous promise for broadening treatment options and giving patients more tools in their fight against cancer. What we’ve shared here is just a starting point—an overview meant to help doctors and patients work together in a more informed way. Every cancer behaves differently, and every patient’s journey is unique, so these combinations are best understood as a framework to guide treatment.
Though alternative treatments can be stigmatized, keep in mind the approach need not be “all or nothing”. Talk to your doctor and work with your patients. Above all, remain hopeful and look forward with bravery.
📚 More Cancer Care Resources
IMA is dedicated to creating and curating vital cancer resources. This mission began with Dr. Marik’s Cancer Care monograph, but since then it has become a focus for many of our contributors. Have a look at these extended cancer resources below:
 | A guest post by
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I'm not a doctor but I have to ask those of you who are: Do y'all find it insulting to have medical boards and government agencies dictating "protocols" to you, i.e. one-size-fits-all treatments? Is that practicing medicine?
God bless you for all you have done and continue to do for people with cancer!