Repurposed drugs and radiotherapy

Content:

1. Repurposed drugs and radiotherapy – how safe is it (scroll down)
2. Difference in suitability for radiation compared to chemo (scroll down)
3. Suitability ranking (scroll down)

1. Repurposed drugs and radiotherapy – how safe is it

In recent years, there has been an increased interest in the use of repurposed drugs. These were originally developed for other purposes, but some have proved interesting in combination with radiotherapy. The goal is to improve treatment outcomes by increasing the sensitivity of cancer cells to radiation (radiosensitization) while simultaneously protecting normal tissue from radiation-induced damage. Below, the potential benefits and risks of combining selected repurposed drugs with radiotherapy are reviewed. However, your physician’s assessment will always override any information from this site.

Note

This overview is largely a result of extensive searches using Gemini AI and DeepSeek. I find it extremely difficult to evaluate the validity of the data, though I generally have positive experiences with the results they present. If you are aware of properties or interactions not mentioned on this page, I hope you will contact me. It is virtually impossible for a single person to keep this information completely updated—despite the best of intentions.

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1. Aspirin

Benefits

• Aspirin has anti-inflammatory properties that can potentially reduce radiation-induced inflammation.
• Some studies suggest that aspirin may have a radiosensitizing effect, meaning it can make cancer cells more susceptible to radiation.
• Aspirin also has blood-thinning properties.

Risks

• Increased risk of bleeding, which can be problematic, especially with radiotherapy in areas with high bleeding risk.
• Can cause gastrointestinal side effects.

Specific interactions and risks

• Bleeding risk: Aspirin can increase the risk of bleeding, especially with concurrent use of other blood-thinning medications.
• Gastrointestinal side effects: Increased risk of stomach ulcers and other gastrointestinal issues.
• Radiosensitization: Can potentially increase the effect of radiotherapy, but further research is needed.

Scientific support:

[1] Targeting DAMPs by Aspirin Inhibits Head and Neck Cancer Stem Cells and Stimulates Radio-Sensitization to Proton Therapy (MDPI, 2025)

• Content: A scientific study demonstrating that aspirin functions as a radiosensitizer during proton therapy by eliminating cancer stem cells (CSCs).

[2] Aspirin enhances radio/chemo-therapy sensitivity in C. elegans by inducing germ cell apoptosis and suppresses RAS overactivated tumorigenesis via mtROS-mediated DNA damage and MAPK pathway (Science Direct, 2024)

• Content: Research demonstrating that aspirin increases sensitivity to treatment and suppresses tumor growth through oxidative stress and DNA damage pathways.

[3] The Anti-Metastatic Role of Aspirin in Cancer: A Systematic Review (PMC, 2026)

• Content: A brand new systematic review of aspirin’s role in suppressing the spread of cancer through both platelet-dependent and tumor-internal mechanisms.

2. Celecoxib

Benefits

• Celecoxib is a COX-2 inhibitor with anti-inflammatory and analgesic properties.
• Can potentially reduce radiation-induced inflammation and pain.
• Some studies suggest that COX-2 inhibitors may have radiosensitizing effects.

Risks

• Increased risk of cardiovascular side effects.
• Can cause gastrointestinal side effects.

Specific interactions and risks

• Cardiovascular risks: Increased risk of heart attack and stroke.
• Gastrointestinal side effects: Increased risk of ulcers and other gastrointestinal problems.
• Radiosensitization: Possible enhanced effect of radiotherapy.

Scientific support:

[4] Celecoxib in oncology: targeting the COX-2/PGE2 axis to reprogram the tumor immune microenvironment and enhance multimodal therapy (PMC, 2025)

• Content: An article describing celecoxib’s ability to reprogram the tumor’s immune environment and its synergistic effects with both chemotherapy and radiotherapy.

[5] Association of COX-inhibitors with cancer patients’ survival under chemotherapy and radiotherapy regimens: a real-world data retrospective cohort analysis (PubMed, 2024)

• Content: A retrospective analysis of real-world data showing how COX inhibitors affect survival in patients undergoing various treatment regimens.

[6] The efficacy of celecoxib during chemoradiation in locally advanced head and neck carcinoma; a phase 2 randomized placebo control clinical trial. (International Journal of Cancer Management, CABI, 2021)

• Content: A randomized phase 2 study showing that celecoxib improves survival and delays side effects in the mucous membranes during radiotherapy for head and neck cancer.

3. Desloratadine

Benefits

• Desloratadine is an antihistamine that can reduce allergic reactions and inflammation, which may benefit patients experiencing skin irritation from radiotherapy.

Risks

• Can cause drowsiness and fatigue.

Specific interactions and risks

• Drowsiness and fatigue: May exacerbate fatigue caused by radiotherapy.
• Immune system impact: Possible influence on the immune system’s response to radiation.
• Liver metabolism: Both desloratadine and certain radiation treatments are metabolized in the liver.

Scientific support:

[7] Atezolizumab-induced psoriasis in a patient with metastatic lung cancer-a case report (PubMed, 2020)

• Content: A case report discussing skin reactions and the use of antihistamines during cancer therapy.

[8] The Impact of Antihistamines on Immunotherapy: A Systematic Review (Cureus, 2025)

• Content: A systematic review analyzing how antihistamines interact with cancer treatments and the immune microenvironment

[9] Desloratadine, a Novel Antigrowth Reagent for Bladder Cancer (PMC, 2020)

• Content: A study demonstrating for the first time that desloratadine can directly inhibit the growth and spread of bladder cancer cells, making it relevant as a supplementary treatment.

4. Dipyridamole

Benefits

• Dipyridamole has anti-inflammatory and antithrombotic properties.
• Can potentially protect normal tissue from radiation-induced damage.
• Some studies suggest it may increase blood flow to tumor tissue, potentially improving radiotherapy effectiveness.

Risks

• Can cause headaches and dizziness.

Specific interactions and risks

• Increased blood flow: May enhance the delivery of oxygen and treatment to tumor tissue.
• Tissue protection: Possible protective effect on normal cells against radiation.
• Side effects: Headaches, dizziness, and other systemic side effects.

Scientific support:

[10] Nuclear medicine imaging methods of early radiation-induced cardiotoxicity: a ten-year systematic review (Frontiers in Oncology, 2023)

• Content: A systematic review analyzing nuclear imaging techniques to monitor heart damage after radiotherapy. It describes how pharmacologic stress using dipyridamole allows for the early detection of impaired myocardial blood flow and microvascular dysfunction

[11] Drug Chemistry (Drug Chemistry, 2026)

• Content: An article discussing pharmacological strategies for radiation protection. It notes that pre-radiation administration of dipyridamole improves survival rates and supports hematopoiesis by protecting bone marrow cells from radiation-induced injury.

[12] Enzyme-Induced Shape-Shifting Peptide Nanocarrier Coloaded with Paclitaxel and Dipyridamole Inhibits Platelet Function and Tumor Metastasis (ACS Applied Materials & Interfaces, 2023)

• Content: A study demonstrating that dipyridamole can inhibit tumor-associated platelets to maintain vascular integrity. This mechanism increases the perfusion of therapeutic agents into solid tumors, helping to overcome the hypoxic conditions that often cause radiotherapy failure.

5. Disulfiram

Benefits

• Disulfiram has shown promising results in preclinical studies as a radiosensitizing agent.

Risks

• Can cause severe side effects, especially with concurrent alcohol consumption.
• Requires further research to establish safety and efficacy in clinical practice.

Specific interactions and risks

• Radiosensitization: May significantly increase the effectiveness of radiation therapy.
• Severe side effects: High risk of toxicity if alcohol is consumed during treatment.
• Research status: Clinical safety and effective dosing are still being established.

Scientific support:

[13] Effects of Disulfiram and Copper in Combination with Temozolomide on Survival in Rat Glioma Model (PMC, 2026)

• Content: A new study showing how the combination of disulfiram and copper can increase survival and reduce tumor size in brain tumors.

[14] Disulfiram Upgrades the Radiosensitivity of Osteosarcoma by Enhancing Apoptosis and P53-Induced Cell Cycle Arrest (PubMed, 2019)

• Content: Research demonstrating that disulfiram makes bone cancer cells more vulnerable to radiation by triggering cell cycle arrest.

[15] A Phase 1/2 Study of Disulfiram and Copper With Concurrent Radiation Therapy and Temozolomide for Patients With Newly Diagnosed Glioblastoma (PubMed, 2023)

• Content: A phase 1/2 trial evaluating the safety and efficacy of combining disulfiram with standard radiation and chemo for brain tumors.

6. Doxycycline

Benefits

• Doxycycline has anti-inflammatory and antiproliferative properties.
• Some studies suggest it may protect normal tissue from radiation-induced damage.

Risks

• Can cause gastrointestinal side effects and photosensitivity.

Specific interactions and risks

• Tissue protection: Possible protective effect against radiation damage in healthy cells.
• Gastrointestinal side effects: Risk of nausea, vomiting, and diarrhea.
• Photosensitivity: Increased sensitivity to sunlight.

Scientific support:

[16] The Interplay among Radiation Therapy, Antibiotics and the Microbiota: Impact on Cancer Treatment Outcomes (MDPI, 2023)

• Content: A review article discussing how antibiotics like doxycycline affect the microbiome and treatment outcomes in radiotherapy.

[17] Enhanced radiosensitivity of pancreatic cancer achieved through inhibition of Cyclin-dependent kinase 1 (PubMed, 2019)

• Content: A study exploring mechanisms that can be targeted by agents like doxycycline to improve radiation response in pancreatic cancer.

[18] A Brief look at antitumor effects of doxycycline in the treatment of colorectal cancer and combination therapies (PubMed, 2022)

• Content: A review of doxycycline’s antitumor mechanisms in colorectal cancer. It describes how the drug inhibits tumor growth and potentially enhances chemo- and immunotherapy.

7. Fenbendazole

Benefits

• Fenbendazole has shown promising results in preclinical studies as an antitumor agent.

Risks

• Requires further research to establish safety and efficacy in clinical practice.
• Limited documentation regarding its use in combination with radiotherapy.

Specific interactions and risks

• Antitumor effect: Potential direct action against cancer cell survival.
• Research status: Clinical safety and human dosages are not yet established.
• Limited evidence: Very few studies exist regarding its interaction with radiation.

Scientific support:

[19] Fenbendazole Exhibits Antitumor Activity Against Cervical Cancer Through Dual Targeting of Cancer Cells and Cancer Stem Cells: Evidence from In Vitro and In Vivo Models (PubMed, 2025)

• Content: A study exploring how fenbendazole targets resistant cancer stem cells by disrupting microtubule dynamics and arresting the cell cycle. This mechanism is critical for sensitizing aggressive tumors that are typically resistant to standard radiation and chemotherapy.

[20] Fenbendazole and Diisopropylamine Dichloroacetate Exert Synergistic Anti-cancer Effects by Inducing Apoptosis and Arresting the Cell Cycle in A549 Lung Cancer Cells (PubMed, 2022)

• Content: Research showing synergistic effects of fenbendazole in lung cancer cells, though radiation was not the primary focus.

[20] Mebendazole or Fenbendazole: Safety and precautions (CancerChoices, 2025)

• Content: A clinical review of benzimidazoles in oncology, highlighting their emerging role in combination with radiation. It discusses the current state of evidence and provides context for using these agents in multimodal treatment plans.

8. Ivermectin

Benefits

• Ivermectin has shown promising results in preclinical studies as an antitumor and radiosensitizing agent.

Risks

• Requires further research to establish safety and efficacy in clinical practice.

Specific interactions and risks

• Antitumor effect: May inhibit several signaling pathways critical for cancer growth.
• Radiosensitization: Potentially increases the efficacy of radiotherapy.
• Research status: More clinical evidence is needed to confirm benefits in humans.

Scientific support:

[22] Ivermectin modulates lung toxicity induced by γ-radiation viaTLR4/ NF-κβ /MAPK pathways (Research Square, 2021)

• Content: A study investigating how ivermectin can reduce radiation-induced lung damage by modulating inflammatory pathways.

[23] Persistent elevation of lysophosphatidylcholine promotes radiation brain necrosis with microglial recruitment by P2RX4 activation (PubMed, 2021)

• Content: Research discussing mechanisms of radiation damage where agents like ivermectin might play a modulatory role.

[24] Synergistic potential of Ivermectin and doxorubicin in oral squamous cell carcinoma: an in vitro investigation (PMC, 2026)

• Content: A study showing that ivermectin works synergistically with conventional treatment by increasing oxidative stress and inducing cell death in oral cancer.

9. LDN (low-dose naltrexone)

Benefits

• LDN can modulate the immune system and reduce inflammation, which may be beneficial for patients experiencing radiotherapy side effects.

Risks

• Can cause sleep disturbances and other minor side effects.

Specific interactions and risks

• Immunomodulation: Potentially beneficial effect on the body’s immune response.
• Inflammation reduction: May reduce the systemic and local inflammation caused by radiation.
• Side effects: Sleep disturbances and vivid dreams are common.

Scientific support:

[25] Leveraging an Open Science Drug Discovery Model to Develop CNS-Penetrant ALK2 Inhibitors for the Treatment of Diffuse Intrinsic Pontine Glioma (PubMed, 2020)

• Content: A study describing new drug discovery efforts for brain tumors where immune-modulating agents are often considered part of the broader strategy.

[26] Low-Dose Naltrexone as an Adjuvant in Combined Anticancer Therapy (PMC, 2024)

• Content: A systematic review summarizing the evidence for LDN as a supplement that can reduce tumor size and improve quality of life during treatment.

[27] Low-Dose Naltrexone as an Adjuvant in Combined Anticancer Therapy (MDPI, 2018)

• Content: A review of the potential for LDN to serve as a supporting agent in various cancer treatment protocols.

10. Melatonin

Benefits

• Melatonin has antioxidant and anti-inflammatory properties.
• Can potentially protect normal tissue from radiation-induced damage.
• Some studies suggest it may have a radiosensitizing effect on tumor cells.
• Helps with sleep disturbances often associated with cancer treatment.

Risks

• Can cause drowsiness and changes in sleep patterns.
• There are some conflicting results regarding melatonin and specific cancer treatments.

Specific interactions and risks

• Tissue protection: May serve as a radioprotector for healthy cells.
• Radiosensitization: Potentially enhances the destruction of cancer cells.
• Sleep patterns: May cause drowsiness or shift the circadian rhythm.
• Hormonal influence: Must be considered in hormone-sensitive cancers due to its biological activity.

Scientific support:

[28] Therapeutic potential of melatonin for breast cancer radiation therapy patients (Taylor & Francis, 2017)

• Content: A study discussing how melatonin can improve outcomes and reduce side effects in breast cancer patients undergoing radiation.

[29] Melatonin increases overall survival of prostate cancer patients with poor prognosis after combined hormone radiation treatment (PubMed, 2020)

• Content: Research showing improved survival in prostate cancer patients when melatonin was added to a combined treatment regimen.

[30] Radioprotective Effects of Combined Melatonin and Famotidine Treatment on Radiation Induced Apoptosis in Peripheral Blood Leukocytes of Breast Cancer Patients and Normal Individuals (PubMed, 2021)

• Content: Research documenting that melatonin can help protect blood cells from the damaging effects of radiation.

11. Metformin

Benefits

• Metformin has shown promising results in preclinical studies as an antitumor and radiosensitizing agent.
• Can potentially reduce radiation-induced inflammation.

Risks

• Can cause gastrointestinal side effects.
• Requires further research to establish safety and efficacy in clinical practice.

Specific interactions and risks

• Antitumor effect: Targets metabolic pathways in cancer cells.
• Radiosensitization: May increase the susceptibility of tumors to radiation.
• Gastrointestinal side effects: Common risk of nausea and diarrhea.

Scientific support:

[31] Evaluation of the effect of metformin as a radiosensitiser in solid tumours: A systematic review (PMC, 2025)

• Content: A systematic review evaluating metformin’s ability to make solid tumors more sensitive to radiotherapy in clinical practice.

[31A] Evaluation of the effect of metformin as a radiosensitiser in solid tumours: A systematic review (PubMed, 2020)

• Content: A systematic review analyzing the evidence for metformin as a radiosensitizer across various types of solid tumors.

[32] Survival and Radiotherapy-Related Adverse Events in Patients Receiving Radiotherapy and Concurrent Metformin (PMC, 2025)

• Content: A meta-analysis investigating metformin’s impact on survival and side effects (including heart protection) in patients undergoing radiotherapy.

[33] Preventive Effect of Metformin in Radiation-Induced Xerostomia (PubMed, 2021)

• Content: Research investigating whether metformin can prevent dry mouth caused by radiation to the head and neck.

12. NSAIDs (Non-steroidal anti-inflammatory drugs)

Benefits

• NSAIDs have anti-inflammatory and analgesic properties.
• Can potentially reduce radiation-induced inflammation and pain.

Risks

• Increased risk of gastrointestinal and cardiovascular side effects.
• Can increase the risk of bleeding.
• May decrease kidney function.

Specific interactions and risks

• Gastrointestinal side effects: High risk of ulcers and bleeding.
• Cardiovascular risks: Increased risk of heart attack and stroke with certain NSAIDs.
• Bleeding risk: Systemic impact on platelet function.
• Renal function: Possible impairment of kidney health.

Scientific support:

[34] Targeting cancer-related inflammation with non-steroidal anti-inflammatory drugs: Perspectives in pharmacogenomics (PubMed, 2022)

• Content: An article reviewing the latest advances in using NSAIDs to improve the efficacy of existing cancer treatments by controlling inflammation.

[35] Combination of radiotherapy and immunotherapy in duality with the protumoral action of radiation (PubMed, 2024)

• Content: An article discussing how anti-inflammatory drugs can be used to modulate the immune environment and improve the results of combined radiotherapy and immunotherapy.

[36] The radiation- and chemo-sensitizing capacity of diclofenac can be predicted by a decreased lactate metabolism and stress response (PubMed, 2024)

• Content: Research exploring the metabolic mechanisms by which diclofenac sensitizes tumors to treatment.

13. Plaquenil (Hydroxychloroquin)

Benefits

• Plaquenil has anti-inflammatory and immunomodulating properties.
• Some studies suggest it may have a radiosensitizing effect by inhibiting autophagy.

Risks

• Can cause visual disturbances and other side effects.
• Requires further research to establish safety and efficacy in clinical practice.

Specific interactions and risks

• Radiosensitization: May block the survival mechanism cancer cells use to resist radiation.
• Visual disturbances: Risk of retinal damage with long-term use.
• Immune modulation: Possible influence on the inflammatory environment around the tumor.

Scientific support:

[37] Hydroxychloroquine’s diverse targets: a new frontier in precision medicine (PMC, 2025)

• Content: A systematic review of hydroxychloroquine’s mechanisms, including its role in blocking cancer cell survival strategies (autophagy).

[38] Blockage of Autophagy for Cancer Therapy: A Comprehensive Review (PubMed, 2024)

• Content: A comprehensive review of how blocking the cell’s “self-cleaning” process (autophagy) can make cancer cells more susceptible to treatment.

[39] Autophagy Inhibition Increased Sensitivity of Pancreatic Cancer Cells to Carbon Ion Radiotherapy (PubMed, 2021)

• Content: Research showing that blocking autophagy increases the effectiveness of specialized radiation therapy.

14. Propranolol

Benefits

• Propranolol has shown promising results in preclinical studies as an antitumor agent.
• Can potentially reduce radiation-induced inflammation.

Risks

• Can cause bradycardia (slow heart rate) and other cardiovascular side effects.
• Requires further research to establish safety and efficacy in clinical practice.

Specific interactions and risks

• Antitumor effect: May interfere with stress-induced tumor growth pathways.
• Inflammation reduction: Potential to dampen the body’s inflammatory response to treatment.
• Cardiovascular side effects: Risk of low heart rate and blood pressure.

Scientific support:

[40] Beta Blockers with Statins May Decrease All-Cause Mortality in Patients with Cardiovascular Diseases and Locally Advanced Unresectable Non-Small-Cell Lung Cancer after Chemoradiotherapy (Cancers, 2023)

• Content: A retrospective cohort study (non-randomized) analyzing 196 patients. The results show that the use of beta-blockers is associated with a significant reduction in all-cause mortality and improved overall survival in patients receiving radical radiotherapy for lung cancer.

[41] Intensity-modulated radiotherapy and chemotherapy for canine right atrial tumors: A retrospective study of seven dogs (PubMed, 2023)

• Content: A study illustrating how specialized radiotherapy and supportive medications are used to manage aggressive tumors.

[42] Clinical value of propranolol combined with oxaliplatin and tigio in concurrent chemoradiotherapy for locally advanced gastric cancer (PubMed, 2019)

• Content: A study evaluating the clinical benefits of adding propranolol to standard treatment for gastric cancer.

15. Statins

Benefits

• Statins have shown promising results in preclinical studies as antitumor and radiosensitizing agents.
• Can potentially reduce radiation-induced inflammation.

Risks

• Can cause muscle pain and other side effects.
• Requires further research to establish safety and efficacy in clinical practice.

Specific interactions and risks

• Antitumor effect: Interferes with cholesterol pathways necessary for cancer cell growth.
• Radiosensitization: May improve the response rate of tumors to radiation.
• Muscle pain: Risk of myalgia or, in rare cases, more severe muscle damage.

Scientific support:

[43] Impact of statin use on survival and adverse events in patients with cancer receiving radiotherapy: a systematic review and meta-analysis (PMC, 2025)

• Content: A comprehensive meta-analysis of 21 studies showing improved survival in several cancer types when statins are used alongside radiotherapy.

[44] Interactions of radiation therapy with common and innovative systemic treatments: Antidiabetic treatments, antihypertensives, lipid-lowering medications, immunosuppressive medications and other radiosensitizing methods (Science Direct, 2022)

• Content: An article reviewing how common medications like statins interact with radiation and can potentially enhance its effect.

[45] Combining Statins with Radiotherapy for Prostate Cancer: From Photon Experience to Proton Potential (Journal of Clinical Medicine, 2026)

• Content: A narrative review investigating the role of statins as radiosensitizers in cancer treatment. The article documents that statin use is associated with improved biochemical recurrence-free survival and reduced toxicity in patients undergoing radiotherapy for prostate cancer and other solid tumors.

16. Vermox/ Mebendazole

Benefits

• Mebendazole has shown promising results in preclinical studies as an antitumor agent.

Risks

• Requires further research to establish safety and efficacy in clinical practice.
• Limited documentation regarding its use in combination with radiotherapy.

Specific interactions and risks

• Antitumor effect: May inhibit microtubule formation in cancer cells.
• Research status: More trials are needed to define its role in a clinical setting.
• Limited evidence: Sparse data specifically regarding its interaction with radiation therapy.

Scientific support:

[46] Mebendazole Increases Anticancer Activity of Radiotherapy in Radiotherapy-Resistant Triple-Negative Breast Cancer Cells (PubMed, 2022)

• Content: A study showing that mebendazole significantly increases the effect of radiotherapy, even in otherwise radiation-resistant breast cancer cells, by promoting immune system attacks.

[47] Anticancer Effect of Benzimidazole Derivatives, Especially Mebendazole, on Triple-Negative Breast Cancer (TNBC) and Radiotherapy-Resistant TNBC In Vivo and In Vitro (PubMed, 2021)

• Content: Research showing that mebendazole can overcome resistance to radiation in triple-negative breast cancer by inducing DNA damage.

[48] Mebendazole and radiation in combination increase survival through anticancer mechanisms in an intracranial rodent model of malignant meningioma (PubMed, 2020)

• Content: Research in an animal model showing increased survival when mebendazole is combined with radiotherapy for brain tumors.

Conclusion

The use of repurposed drugs in combination with radiotherapy represents a promising area of cancer research. However, it must be noted that further research is necessary to firmly establish safety and efficacy. If you are considering using repurposed drugs in connection with radiotherapy, you should always consult your qualified healthcare provider to discuss potential benefits and risks.

See also Holistic doctors in DK

To be continued…

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Page created: 28.03.25. Last updated April 8, 2026

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