Top 10 Repurposed Drugs and Supplements for Terminal or Stage 4 Cancer (2025)

Top 10 Repurposed Drugs and Supplements for Terminal or Stage 4 Cancer (2025) - ChatGPT

By Editorial Team - April 19, 2025

Introduction: Why This Guide Matters

A diagnosis of Stage 4 or terminal cancer can feel overwhelming, and it's natural to look beyond standard treatments for additional ways to improve well-being or possibly extend life. Many patients and caregivers search for integrative or alternative strategies—and find confusing, sometimes contradictory, information online.

Credit: ChatGPT

This guide was created to bring clarity, evidence, and hope to those looking for complementary approaches. It highlights supplements and repurposed medications—drugs originally developed for non-cancer conditions—that show potential as adjunctive cancer therapies. These therapies are not meant to replace chemotherapy, immunotherapy, or surgery, but rather to be explored alongside conventional care, with guidance from a qualified healthcare provider.

🎯 What’s special about these therapies?

Many have been studied in clinical trials or have strong biological plausibility.
Some are already used in cancer centers globally (e.g., Japan, Europe).
They may improve quality of life, immune function, energy, sleep, or even enhance the effect of cancer treatment.

Some of the therapies listed—like metformin, melatonin, or curcumin—have decades of safety data and are easy to obtain. Others, such as fenbendazole or disulfiram, are more experimental and require careful discussion with your oncologist. The goal is not false hope, but rather realistic, evidence-informed choices to empower your journey.

📝 Consider this guide a starting point:

Highlight a few options that interest you.
Research them further.
Discuss with your medical team.
Consider tracking how you feel if you start something new.

Healing is not one-size-fits-all. Every person, every tumor, and every response is unique. But informed patients are powerful partners in their care—and this guide is here to support you every step of the way.

Repurposed Drugs for Cancer (Under Clinical Review)

1. Metformin

Original Use: Type 2 diabetes
Cancer Evidence: Reduces tumor growth signals (mTOR pathway); may improve survival in breast, endometrial, and pancreatic cancers
Combination Use: Sometimes combined with chemotherapy
Dosing Tip: Typical cancer dosing is 500–2,000 mg/day; start low and monitor for GI effects
Source: PMC

2. Mebendazole

Original Use: Antiparasitic
Cancer Evidence: Disrupts microtubules in cancer cells; preclinical success in brain, lung, and colon cancers
Dose: Often higher than antiparasitic use; reported ranges 100–500 mg/day in divided doses
Source: PMC

3. Aspirin

Original Use: Pain reliever, anti-inflammatory
Cancer Evidence: Reduces recurrence and mortality in colorectal cancer; ongoing research in breast and prostate cancer
Caution: Can cause bleeding; discuss with doctor if on blood thinners
Dosing Tip: 75–325 mg daily depending on clinical context
Source: PMC

4. Propranolol

Original Use: Beta-blocker for hypertension
Cancer Evidence: May inhibit angiogenesis and metastasis; promising in angiosarcoma and breast cancer
Mechanism: Blocks stress-induced tumor growth signaling
Dosing Tip: Typical range 20–80 mg twice daily; must be prescribed and titrated
Source: PMC

5. Doxycycline

Original Use: Antibiotic
Cancer Evidence: Targets mitochondrial function in cancer cells; shown to reduce breast cancer stem cells
Other Uses: Anti-inflammatory and anti-angiogenic properties
Dosing Tip: 100–200 mg/day in divided doses
Source: PMC

6. Ivermectin

Original Use: Antiparasitic
Cancer Evidence: Inhibits WNT signaling and promotes cell death in leukemia and brain cancers
Current Status: Early-stage research; not yet widely recommended clinically
Dosing Tip: Experimental use ranges from 12–36 mg per week; physician oversight needed
Source: PMC

7. Fenbendazole

Original Use: Antiparasitic (veterinary)
Cancer Evidence: Induces apoptosis and inhibits glucose metabolism in cancer cells
Status: Not approved for human use; anecdotal reports only
Dosing Tip: Common anecdotal use: 222 mg/day, 3–4 days per week (consult physician)
Source: IIAR Journals

8. Statins (e.g., Simvastatin)

Original Use: Cholesterol-lowering
Cancer Evidence: Inhibits HMG-CoA reductase, disrupting cancer cell growth; possible benefit in breast and colorectal cancers
Dosing Tip: 10–40 mg/day depending on tolerance and liver function
Source: ScienceDirect

9. Cimetidine

Original Use: Antacid (H2 receptor blocker)
Cancer Evidence: Improves survival in colorectal cancer; may enhance immune response
Mechanism: Blocks suppressive effects of histamine on immune cells
Dosing Tip: 800–1,200 mg/day in divided doses
Source: PMC

10. Disulfiram (Antabuse)

Original Use: Alcohol dependence
Cancer Evidence: Inhibits ALDH enzyme in cancer stem cells; increased effect when combined with copper
Status: Ongoing clinical trials in glioblastoma, breast, and prostate cancers
Dosing Tip: Typical oncology trials use 250–500 mg/day with copper supplementation (1–2 mg)
Source: PMC

Supplements (Complementary Therapies)

1. Medical Cannabis (CBD/THC)

Use: Pain, appetite loss, sleep, nausea
Evidence: Reduces tumor size in preclinical studies; improves quality of life in palliative care
Form: Oils, capsules, inhalation
Dosing Tip: Begin with low doses; titrate up slowly (e.g., 2.5–5 mg THC or CBD)
Note: Legal status varies by region
Source: The Guardian

2. Melatonin

Use: Sleep support, immune boost
Evidence: Improves survival in late-stage cancers; enhances effectiveness of radiation
Form: Tablets, drops
Dosing Tip: Often used in higher doses (10–20 mg) in oncology settings, taken before bedtime
Source: PMC

3. AHCC (Mushroom Extract)

Use: Immune support
Evidence: Enhances NK cell activity; used alongside chemotherapy in Japan
Form: Capsules
Dosing Tip: Common dose is 1–3 grams daily, divided
Learn More

4. Vitamin D

Use: Bone, immune health
Evidence: Higher levels associated with better survival in multiple cancers
Form: Drops, capsules (with K2 recommended)
Dosing Tip: 2,000–5,000 IU daily; test levels to personalize dosing
Testing: Ask your provider to check your 25(OH)D levels
Learn More

5. Curcumin (Turmeric Extract)

Use: Anti-inflammatory, antioxidant
Evidence: Inhibits multiple cancer pathways; well tolerated
Form: Enhanced with piperine or liposomal for better absorption
Best With: Taken with fat-containing meals
Dosing Tip: 500–1,500 mg per day in divided doses
Learn More

6. Turkey Tail Mushroom

Use: Immune stimulation
Evidence: Contains PSK and PSP polysaccharides that stimulate immune cells
Form: Teas, capsules
Approved Use: Used in Japan as part of standard cancer therapy
Dosing Tip: 1–3 grams daily of standardized extract
Learn More

7. Fish Oil (Omega-3)

Use: Inflammation, weight stabilization
Evidence: Reduces cachexia; may slow tumor progression
Form: Capsules, liquid
Tip: Look for high EPA formulations
Dosing Tip: 2–4 grams combined EPA/DHA daily
Learn More

8. CoQ10

Use: Fatigue, heart protection
Evidence: Protects against cardiotoxic effects of chemotherapy; supports cellular energy
Form: Ubiquinol is the preferred bioavailable form
Dosing Tip: 100–300 mg daily with meals
Learn More

9. Flaxseed

Use: Hormonal balance, digestion
Evidence: Contains lignans that may inhibit estrogen-sensitive tumors
Form: Freshly ground seed, oil (cold-pressed)
Dose: 1–2 tablespoons daily
Tip: Grind fresh daily for best potency
Learn More

10. American Ginseng

Use: Cancer-related fatigue
Evidence: Shown in clinical trials to reduce fatigue in advanced cancer patients
Form: Tea, capsules
Note: Use standardized extract (e.g., Ginsenoside content)
Dosing Tip: 1–2 grams per day of standardized extract
Learn More

Use With Caution:

Green Tea Extract (EGCG): May cause liver damage at high doses
Resveratrol: Promising in lab studies, but lacks strong clinical validation
Quercetin: Some anti-cancer potential; avoid high doses without supervision

Hallmarks of Cancer & Their Matching Agents

The repurposed drugs and supplements listed in this guide align with several of the "Hallmarks of Cancer" as originally defined by Hanahan and Weinberg (Cell 2000, Cell 2011, AACR 2022)—key biological capabilities acquired during cancer development.

Note: Cancer cells have a number of characteristics that distinguish them from normal cells. These characteristics are known as the "cancer hallmarks".

Table: Hallmarks of Cancer & Their Matching Agents

Hallmark	Matching Agents
1. Sustaining Proliferative Signaling	- Metformin: Inhibits mTOR pathway and insulin/IGF-1 signaling. - Statins: Interrupt HMG-CoA reductase, affecting signaling. - Curcumin: Suppresses growth factors (EGF, VEGF).
2. Evading Growth Suppressors	- Aspirin: Modulates p53 and COX pathways. - Curcumin: Reactivates tumor suppressor genes. - Disulfiram (with copper): Inhibits NF-κB and ALDH, promoting suppressor pathways.
3. Resisting Cell Death (Apoptosis)	- Mebendazole: Induces apoptosis via microtubules. - Fenbendazole: Triggers mitochondrial apoptosis. - Doxycycline: Targets mitochondria. - Ivermectin: Modulates chloride channels. - Melatonin: Promotes apoptosis via ROS and p53.
4. Enabling Replicative Immortality	- Curcumin: Downregulates telomerase. - Melatonin: Downregulates telomerase. - Doxycycline: Inhibits telomerase-positive cancer stem cells.
5. Inducing Angiogenesis	- Propranolol: Reduces VEGF production. - AHCC: Modulates cytokines affecting angiogenesis. - Fish Oil: Inhibits angiogenesis via PPAR and eicosanoid signaling.
6. Activating Invasion & Metastasis	- Propranolol: Blocks stress-induced invasion. - Statins: Reduce migration via cytoskeletal effects. - Curcumin: Inhibits MMPs (tissue barrier degradation).
7. Deregulating Cellular Energetics	- Fenbendazole: Disrupts glucose metabolism. - Metformin: Disrupts glucose metabolism. - Disulfiram: Disrupts mitochondrial respiration. - CoQ10: Supports normal mitochondrial function.
8. Avoiding Immune Destruction	- Cimetidine: Enhances immune response via histamine receptor blockade. - AHCC: Activates NK cells and macrophages. - Turkey Tail Mushroom: Activates NK cells and macrophages. - Melatonin: Modulates immune surveillance.
9. Genome Instability & Mutation	- Curcumin: Antioxidant, protects against DNA damage. - Resveratrol: Antioxidant, protects against DNA damage. - Doxycycline: Disrupts mitochondrial integrity in cancer stem cells.
10. Tumor-Promoting Inflammation	- Aspirin: Inhibits COX enzymes. - Fish Oil: Reduces pro-inflammatory prostaglandins. - Curcumin: Broad anti-inflammatory effects. - Melatonin: Broad anti-inflammatory effects.

Here's how they map onto those hallmarks:

1. Sustaining Proliferative Signaling

Cancer cells keep dividing uncontrollably.

Metformin: Inhibits the mTOR pathway and insulin/IGF-1 signaling.
Statins: Interrupt HMG-CoA reductase, affecting membrane signaling and growth.
Curcumin: Suppresses growth factors like EGF and VEGF.

2. Evading Growth Suppressors

They bypass tumor suppressor mechanisms like p53.

Aspirin: Modulates p53 and COX pathways, affecting inflammation-linked growth.
Curcumin: Reactivates tumor suppressor genes via epigenetic modulation.
Disulfiram (with copper): Inhibits NF-κB and ALDH, promoting tumor suppressor pathways.

3. Resisting Cell Death (Apoptosis)

They avoid programmed death that normally removes defective cells.

Mebendazole: Induces apoptosis by destabilizing microtubules.
Fenbendazole: Triggers mitochondrial apoptosis and interferes with glucose metabolism.
Doxycycline: Targets mitochondria to disrupt cancer cell survival.
Ivermectin: Enhances apoptosis by modulating chloride channels and mitochondrial dysfunction.
Melatonin: Promotes apoptosis via ROS generation and p53 activation.

4. Enabling Replicative Immortality

They maintain telomeres and keep dividing indefinitely.

Curcumin & Melatonin: Downregulate telomerase activity in cancer cells.
Doxycycline: Can inhibit cancer stem cell populations that are telomerase-positive.

5. Inducing Angiogenesis

They create new blood vessels to fuel growth.

Propranolol: Anti-angiogenic; reduces VEGF production.
AHCC: Modulates cytokines that can affect angiogenesis.
Fish Oil: May inhibit angiogenesis via PPAR modulation and eicosanoid signaling.

6. Activating Invasion & Metastasis

They break out from original tissue and spread.

Propranolol: Blocks stress-induced invasion via β-adrenergic pathways.
Statins: Reduce migration and invasion by affecting cytoskeletal function.
Curcumin: Inhibits MMPs (enzymes that degrade tissue barriers).

7. Deregulating Cellular Energetics

They use altered metabolism (e.g., Warburg effect) to grow.

Fenbendazole & Metformin: Disrupt glucose metabolism.
Disulfiram: Disrupts mitochondrial respiration.
CoQ10: Supports normal mitochondrial function, indirectly opposing cancer's metabolic reprogramming.

8. Avoiding Immune Destruction

They hide from or suppress immune responses.

Cimetidine: Enhances immune response by blocking histamine receptors.
AHCC & Turkey Tail Mushroom: Activate NK cells and macrophages.
Melatonin: Modulates immune surveillance and cytokine activity.

9. Genome Instability & Mutation

They accumulate mutations to evolve rapidly.

Curcumin & Resveratrol: Antioxidants that protect against DNA damage.
Doxycycline: May indirectly affect mutation rates by disrupting mitochondrial integrity in cancer stem cells.

10. Tumor-Promoting Inflammation

Chronic inflammation supports cancer growth.

Aspirin: Inhibits COX enzymes, key drivers of inflammatory pathways.
Fish Oil: Reduces pro-inflammatory prostaglandins.
Curcumin & Melatonin: Broad anti-inflammatory effects.

This guide is for informational purposes only. Do not begin any new treatment or supplement without professional medical advice. Talk to your care team about clinical trials, off-label options, and complementary therapies tailored to your condition.