{"id":32980,"date":"2025-03-21T19:25:39","date_gmt":"2025-03-21T18:25:39","guid":{"rendered":"https:\/\/jegharkraeft.dk\/?p=32980"},"modified":"2026-04-11T18:54:31","modified_gmt":"2026-04-11T17:54:31","slug":"doxycycline","status":"publish","type":"post","link":"https:\/\/jegharkraeft.dk\/en\/doxycycline\/","title":{"rendered":"Doxycycline and cancer. The COC Protocol. Antibiotics."},"content":{"rendered":"\n<div class=\"wp-block-group alignfull is-style-section-5 has-contrast-color has-base-background-color has-text-color has-background has-link-color wp-elements-a01913b26b4faa9e36b8e3489419aa92 has-global-padding is-layout-constrained wp-block-group-is-layout-constrained is-style-section-5--2\" id=\"menu\" style=\"margin-top:0;margin-bottom:0;padding-top:var(--wp--preset--spacing--50);padding-bottom:var(--wp--preset--spacing--50)\">\n<div class=\"wp-block-columns alignwide is-layout-flex wp-container-core-columns-is-layout-ca2dd60b wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\">\n<h2 class=\"wp-block-heading has-custom-int-link-p-sort-1-color has-text-color has-link-color wp-elements-85c9ab605a9af581478ba1bfba8fd611\"><span class=\"ez-toc-section\" id=\"Treatments\"><\/span><a href=\"https:\/\/jegharkraeft.dk\/en\/cancer-treatments-overview\/\">Treatments<\/a><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<h3 class=\"wp-block-heading has-custom-int-link-p-sort-1-color has-text-color has-link-color wp-elements-52532d4beacf4a32227a79286a8276fc\"><span class=\"ez-toc-section\" id=\"Complementary_and_Alternative_Treatments\"><\/span><a href=\"https:\/\/jegharkraeft.dk\/en\/alternative-cancer-treatments-overview\/\">Complementary and Alternative Treatments<\/a><span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<div class=\"wp-block-group has-custom-interne-links-color has-text-color has-link-color wp-elements-55454b7bc22b75f8eee99c375bb137dc has-global-padding is-layout-constrained wp-block-group-is-layout-constrained\">\n<ol class=\"wp-block-list\">\n<li class=\"has-custom-int-link-p-sort-1-color has-text-color has-link-color wp-elements-0b2e7e9b07152882fe8fbe3c7509b15e\"><a href=\"https:\/\/jegharkraeft.dk\/en\/akupunktur\/\">Physical treatments<\/a>\n<ul class=\"wp-block-list\">\n<li class=\"has-custom-int-link-p-sort-1-color has-text-color has-link-color wp-elements-ac1000d33861f9f2d320254351deacb6\"><a href=\"https:\/\/jegharkraeft.dk\/en\/repurposed-drugs\/\"><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-custom-hvid-tekst-color\">Repurposed Drugs &#8211; General<\/mark><\/a>\n<ol class=\"wp-block-list\">\n<li class=\"has-custom-int-link-p-sort-1-color has-text-color has-link-color wp-elements-780fac237d6d09f0087842050420bfba\"><a href=\"https:\/\/jegharkraeft.dk\/en\/aspirin\/\">Painkillers and anti-inflammatory drugs<\/a><\/li>\n\n\n\n<li class=\"has-custom-int-link-p-sort-1-color has-text-color has-link-color wp-elements-fad7d0169f73487a5cb08247fb6344df\"><a href=\"https:\/\/jegharkraeft.dk\/en\/dipyridamole\/\">Heart and circulatory medications<\/a><\/li>\n\n\n\n<li class=\"has-custom-int-link-p-sort-1-color has-text-color has-link-color wp-elements-6ce0ef2511aa9d74c88ddb3f816ba9be\"><a href=\"https:\/\/jegharkraeft.dk\/en\/doxycycline\/\"><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-custom-hvid-tekst-color\">Antibiotics and antiparasitic agents<\/mark><\/a>\n<ul class=\"wp-block-list\">\n<li class=\"has-custom-her-st-r-du-color has-text-color has-link-color wp-elements-b7386e9e625468ef0c29d1cdc4b0572c\"><a href=\"#doxycycline\">Doxycycline (scroll down)<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/jegharkraeft.dk\/en\/fenbendazole\/\">Fenbendazole<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/jegharkraeft.dk\/en\/ivermectin\/\">Ivermectin<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/jegharkraeft.dk\/en\/?p=33036\">Mebendazole<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/jegharkraeft.dk\/en\/?attachment_id=33051\">Niclosamide<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/jegharkraeft.dk\/en\/plaquenil\/\">Plaquenil<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/jegharkraeft.dk\/en\/?p=33036\">Vermox<\/a><\/li>\n<\/ul>\n<\/li>\n\n\n\n<li class=\"has-custom-int-link-p-sort-1-color has-text-color has-link-color wp-elements-a99575c8ffb4e827783ab6d56f16ed45\"><a href=\"https:\/\/jegharkraeft.dk\/en\/metformin\/\">Diabetes medication<\/a><\/li>\n\n\n\n<li class=\"has-custom-int-link-p-sort-1-color has-text-color has-link-color wp-elements-6c31e64b006d888e2e94cb9770a3c32c\"><a href=\"https:\/\/jegharkraeft.dk\/en\/low-dose-naltrexone\/\">Agents affecting hormones and signaling substances<\/a><\/li>\n\n\n\n<li class=\"has-custom-int-link-p-sort-1-color has-text-color has-link-color wp-elements-dd7ca0bc23a9ec3ca6e860ef8de7693a\"><a href=\"https:\/\/jegharkraeft.dk\/en\/disulfiram\/\">Other medications<\/a><\/li>\n\n\n\n<li class=\"has-custom-int-link-p-sort-1-color has-text-color has-link-color wp-elements-66a0e4204f5201bcc8494f5822b38efe\"><a href=\"https:\/\/jegharkraeft.dk\/en\/the-coc-protocol\/\">COC Protocol<\/a><\/li>\n<\/ol>\n<\/li>\n\n\n\n<li class=\"has-custom-int-link-p-sort-1-color has-text-color has-link-color wp-elements-9504e56e950d068c15963cbdbf1fdaaf\"><a href=\"https:\/\/jegharkraeft.dk\/en\/no-medicine-plan-b\/\">No medication \u2013 Plan B<\/a><\/li>\n\n\n\n<li class=\"has-custom-int-link-p-sort-1-color has-text-color has-link-color wp-elements-50bb8d7b4bb216418ba3c0d4a402648c\"><a href=\"https:\/\/jegharkraeft.dk\/en\/repurposed-drugs-and-chemotherapy\/\">Repurposed drugs and chemotherapy<\/a><\/li>\n\n\n\n<li class=\"has-custom-int-link-p-sort-1-color has-text-color has-link-color wp-elements-af88e7f595afd58f141d2c174a141555\"><a href=\"https:\/\/jegharkraeft.dk\/en\/repurposed-drugs-and-radiotherapy\/\">Repurposed drugs and radiation therapy<\/a><\/li>\n\n\n\n<li class=\"has-custom-int-link-p-sort-1-color has-text-color has-link-color wp-elements-7098df34ebce445cd1790d85e10991eb\"><a href=\"https:\/\/jegharkraeft.dk\/en\/flcccs-ranking\/\">FLCCC\u2019s ranking of repurposed drugs<\/a><\/li>\n\n\n\n<li class=\"has-custom-int-link-p-sort-1-color has-text-color has-link-color wp-elements-4c827eb85783b3d07583409effc04d57\"><a href=\"https:\/\/jegharkraeft.dk\/en\/brain-metastases-and-bloodbrain-barrier\/\">Brain metastases and the blood-brain barrier<\/a><\/li>\n\n\n\n<li class=\"has-custom-int-link-p-sort-1-color has-text-color has-link-color wp-elements-cf6cfac91ed1b7d193bc5d25a711b818\"><a href=\"https:\/\/jegharkraeft.dk\/en\/bombs-fire-extinguishers-and-timing\/\">Bombs, fire extinguishers, and timing<\/a><\/li>\n<\/ul>\n<\/li>\n<\/ol>\n<\/div>\n<\/div>\n\n\n\n<div class=\"wp-block-column is-vertically-aligned-center is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:50%\">\n<figure class=\"wp-block-image aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"567\" height=\"430\" src=\"https:\/\/jegharkraeft.dk\/wp-content\/uploads\/2025\/02\/bDoxycyclin.jpeg\" alt=\"Doxycycline kapsler i lysbl\u00e5 og hvid pap\u00e6ske med 14 stk.\" class=\"wp-image-32979\" style=\"aspect-ratio:3\/2;object-fit:cover;width:550px\" srcset=\"https:\/\/jegharkraeft.dk\/wp-content\/uploads\/2025\/02\/bDoxycyclin.jpeg 567w, https:\/\/jegharkraeft.dk\/wp-content\/uploads\/2025\/02\/bDoxycyclin-300x228.jpeg 300w\" sizes=\"auto, (max-width: 567px) 100vw, 567px\" \/><\/figure>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n<div class=\"wp-block-group alignfull is-style-default has-global-padding is-layout-constrained wp-container-core-group-is-layout-b040ace0 wp-block-group-is-layout-constrained has-background\" style=\"margin-top:0;margin-bottom:0;padding-top:var(--wp--preset--spacing--60);padding-right:var(--wp--preset--spacing--20);padding-bottom:var(--wp--preset--spacing--60);padding-left:var(--wp--preset--spacing--20);background-image:url(&apos;https:\/\/jegharkraeft.dk\/wp-content\/uploads\/2025\/02\/bDoxycyclin.jpeg&apos;);background-position:44% 36%;background-size:cover;\">\n<div class=\"gb-element-906497af\">\n<h1 class=\"wp-block-heading\" id=\"doxycycline\"><span class=\"ez-toc-section\" id=\"Doxycycline_and_cancer\"><\/span>Doxycycline and cancer<span class=\"ez-toc-section-end\"><\/span><\/h1>\n\n\n\n<p class=\"wp-block-paragraph\">Doxycycline is a broad-spectrum antibiotic primarily used to fight bacterial infections. However, in recent years, researchers have discovered that this substance may also have an interesting and promising effect on cancer cells. Therefore, doxycycline is being investigated as a potential adjuvant treatment\u2014a treatment used alongside other cancer therapies. Doxycycline is thus a <a href=\"https:\/\/jegharkraeft.dk\/en\/repurposed-drugs\/\">repurposed drug<\/a> for cancer.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Important\"><\/span>Important<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Doxycycline must not be taken simultaneously with dairy products, calcium supplements, or magnesium (e.g., in multivitamins), as these bind the medicine and prevent absorption. Optimally, it should be taken with a large glass of water (at least 200 ml) at least 1 hour before food or bedtime to protect the esophagus. <\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Note:<\/strong> <\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>If it causes stomach pain or nausea on an empty stomach (which is frequent), it may be taken with food. <\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Warning:<\/strong> <\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Regardless of whether you take it with or without food, the meal must not contain dairy products, calcium, or magnesium, as this blocks the effect. Maintain at least a 2-hour interval from dairy products and minerals. It can be taken with food to protect the stomach, as long as it is calcium-free.<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Effect_and_Mechanism_of_Action\"><\/span>Effect and Mechanism of Action<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Although the precise mechanism behind doxycycline&#8217;s cancer-fighting properties is still being investigated, several studies have pointed to the following possible mechanisms:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Inhibition of tumor growth<\/strong> <\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Doxycycline can directly inhibit the growth of certain cancer cells by affecting their cell cycle and inducing cell death (apoptosis). Doxycycline can induce cancer cells to commit suicide.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Counteracting angiogenesis<\/strong> <\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Angiogenesis is the formation of new blood vessels, which cancer tumors need to grow. Doxycycline can inhibit this process, which can slow tumor growth. Cancer tumors need new blood vessels to grow and to be able to spread.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Modulation of the immune system<\/strong> <\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Doxycycline can affect the immune system in various ways, for example, by increasing the activity of certain immune cells, which can help the body fight cancer cells more effectively. Doxycycline can thus improve the immune system&#8217;s ability to fight cancer cells.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Inhibition of metastases<\/strong> <\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Metastases are the spread of cancer cells to other parts of the body. Doxycycline can inhibit this process by affecting the cancer cells&#8217; ability to invade and colonize new tissues.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Inhibition of protein synthesis<\/strong> <\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Doxycycline binds to the ribosomes of bacteria\/cancer cells. Ribosomes are the cells&#8217; protein factories. They read the genetic code in mRNA and use it to build proteins necessary for all living organisms. By binding to cancer cells, they can prevent them from producing the proteins they need to survive and reproduce. Thereby, doxycycline inhibits the protein synthesis of cancer cells. Cancer cells\u2014just like bacteria\u2014divide rapidly and therefore have a high need to produce new proteins. By blocking this process, doxycycline can also prevent cancer cells from growing and dividing.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">The potential for doxycycline in cancer treatment is due to several factors:<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Broad-spectrum effect:<\/strong> <\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Doxycycline may be effective against various types of cancer cells.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Relatively low toxicity:<\/strong> <\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Compared to many chemotherapeutic agents, doxycycline has a relatively low toxicity profile.<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Adjuvant_Treatment\"><\/span>Adjuvant Treatment<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Doxycycline is being investigated as a potential adjuvant treatment for a variety of cancers, including:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Hematological cancers:<\/strong> <\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Such as <a href=\"https:\/\/jegharkraeft.dk\/en\/leukaemi\/\">leukemia<\/a> and <a href=\"https:\/\/jegharkraeft.dk\/en\/lymfekraeft\/\">lymphoma<\/a>.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Solid tumors:<\/strong> <\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Such as <a href=\"https:\/\/jegharkraeft.dk\/en\/brystkraeft\/\">breast cancer<\/a>, <a href=\"https:\/\/jegharkraeft.dk\/en\/lungekraeft\/\">lung cancer<\/a>, and <a href=\"https:\/\/jegharkraeft.dk\/en\/prostatakraeft\/\">prostate cancer<\/a>.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Furthermore, it is used by a number of doctors as an adjuvant treatment for cancer in connection with 3 other drugs in a context called <a href=\"https:\/\/jegharkraeft.dk\/en\/the-coc-protocol\/\">The COC Protocol<\/a>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">It must be emphasized that doxycycline is not a standard treatment for cancer. Research is still in an early phase, and more clinical studies are needed to determine if doxycycline can be a safe and effective treatment for cancer patients. However, it should also be emphasized that quite a few people are prescribed it as an adjuvant treatment against cancer in connection with the aforementioned COC Protocol.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Read about <a href=\"https:\/\/jegharkraeft.dk\/en\/the-coc-protocol\/\">The COC Protocol.<\/a><\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Side_Effects\"><\/span>Side Effects<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Doxycycline is an effective antibiotic, but as with all medicine, it can also cause side effects. These can vary from person to person and depend on several factors, including dose, treatment duration, and the individual&#8217;s general health.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">Common Side Effects<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Gastrointestinal problems<\/strong> <\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This is one of the most common side effects and can include:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Diarrhea<\/li>\n\n\n\n<li>Nausea<\/li>\n\n\n\n<li>Vomiting<\/li>\n\n\n\n<li>Stomach pain<\/li>\n\n\n\n<li>Loss of appetite<\/li>\n\n\n\n<li>Constipation<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Skin reactions<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Rash<\/strong><\/li>\n\n\n\n<li><strong>Increased sensitivity to sunlight (photosensitization):<\/strong> \n<ul class=\"wp-block-list\">\n<li>A common side effect of using doxycycline is increased sensitivity to sunlight. This means that the skin may react more strongly to the sun&#8217;s rays, resulting in sunburn (even with short-term exposure), rash, and\/or itching.\n<ul class=\"wp-block-list\">\n<li><strong>Increased risk of sunburn:<\/strong> You can get sunburned much faster and more severely than normal.<\/li>\n\n\n\n<li><strong>Skin rash:<\/strong> Some people may develop a rash after exposure to sunlight while on doxycycline.<\/li>\n\n\n\n<li><strong>Itching:<\/strong> Your skin may become itchy after being in the sun.<\/li>\n\n\n\n<li><strong>Skin discoloration:<\/strong> In rare cases, doxycycline can lead to changes in skin color after exposure to sunlight.<\/li>\n\n\n\n<li><strong>Photo-onycholysis:<\/strong> This is a rare reaction where your fingernails may begin to detach from the nail bed due to sunlight exposure.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>With fixed, continuous use of doxycycline:<\/strong> If you\u2014as with The COC Protocol\u2014take doxycycline daily without breaks, your skin will be persistently more sensitive to sunlight throughout the treatment period. It is therefore crucial that you take all necessary precautions to protect yourself from the sun every day. This includes avoiding direct sunlight during the most intense hours (between 10 AM and 3 PM), using high-factor sunscreen (SPF 30 or higher, and consider SPF 50 for extra protection), wearing protective clothing (long sleeves, long pants, hat), and sunglasses.\n<ul class=\"wp-block-list\">\n<li><strong>With alternating use (e.g., 1 month doxycycline, 1 month Vermox):<\/strong> Even if you take breaks from doxycycline, there may still be increased sensitivity to sunlight for some days (and up to a week) after you have stopped taking it. Although the highest concentration of doxycycline drops quickly, it can take some time before the medicine is completely out of the body. Therefore, it is recommended that you continue to be extra careful with the sun for at least a week after the doxycycline period ends, before you can be less cautious during the period where you pause (and take Vermox instead). Vermox does not cause increased sensitivity to sunlight. When you resume doxycycline treatment, your sensitivity to the sun will increase again.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">It is important to be consistent with sun protection throughout the doxycycline treatment course, whether it is fixed or in cycles, and for a period after use ends. Be aware that individual reactions can vary, and you should talk to your doctor or practitioner if you experience severe reactions to the sun.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Applies to the entire group<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Unfortunately, photosensitivity is a known side effect for the<strong> entire tetracycline class<\/strong> of antibiotics. This means that other preparations in this group, such as tetracycline and minocycline, can also cause increased sensitivity to sunlight, although the degree of sensitivity may vary slightly between the different tetracyclines. Some sources suggest that minocycline may cause less photosensitivity than doxycycline, but this is still not clarified and must therefore also be considered a potential side effect to be fully aware of.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Fungal infections<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Doxycycline can suppress the natural bacterial flora in the body and thus allow for fungal infections, such as:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Oral thrush<\/li>\n\n\n\n<li>Vaginal yeast infection<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Other side effects<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Headache<\/li>\n\n\n\n<li>Dizziness<\/li>\n\n\n\n<li>Fatigue<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\">Less common but serious side effects<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Liver impact<\/strong> <\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This can be serious and requires immediate medical attention. Symptoms may include:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Jaundice (yellow color in skin and eyes)<\/li>\n\n\n\n<li>Dark urine<\/li>\n\n\n\n<li>Pale stools<\/li>\n\n\n\n<li>Itching<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Kidney problems<\/strong> <\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Doxycycline can in rare cases affect kidney function.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Allergic reactions<\/strong> <\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>These can be mild (e.g., rash) or severe (anaphylactic shock).<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>Side effects in children<\/strong><\/h4>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Discoloration of teeth:<\/strong> <\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Doxycycline can cause permanent discoloration of teeth in children if taken during tooth formation.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Inhibited bone growth:<\/strong> <\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Long-term use of doxycycline in children can affect bone growth.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Note\"><\/span><strong>Note<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Doxycycline <strong>must not be taken with dairy products<\/strong>, as it can reduce the effect. There should be as much time as possible between the intake of Doxycycline and dairy products. <\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Doxycycline <strong>should also not be taken with alcohol<\/strong>, as this can increase the risk of side effects.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Conclusion\"><\/span><strong>Conclusion<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Based on the aforementioned anti-cancer effects, doxycycline has been investigated as a potential treatment for a variety of cancers, including breast cancer, lung cancer, colorectal cancer, and melanoma. Doxycycline is still an off-label medication. However, it must be said to be extremely interesting. As with all other treatment in a cancer context, it is necessary to weigh side effects against the risk of the disease&#8217;s progression if left untreated. If you are considering using doxycycline as part of your cancer treatment, you must talk to your doctor about the benefits and risks. Furthermore, be aware that certain drugs can interact, potentially causing unintended effects when combined. If you are in doubt, it can be checked here: Drugs.com<\/p>\n\n\n\n<p class=\"has-custom-sort-tekst-color has-text-color has-link-color wp-elements-b7e7dfec0593ccd269584eaf690c1487 wp-block-paragraph\"><a rel=\"noreferrer noopener\" href=\"https:\/\/www.drugs.com\/?fbclid=IwZXh0bgNhZW0CMTAAAR2Un76TmB0Yk4p7gHQ4TUFL7cCg_ob3aVB1DcZjT48o-YwFap8riMvnNiQ_aem__ZDuOwAdzVO0yZi5iJKihQ\" target=\"_blank\"><strong>Drugs.com<\/strong><\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">See also <a href=\"https:\/\/jegharkraeft.dk\/en\/repurposed-drugs\/\">Repurposed Drugs<\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">See also <a href=\"https:\/\/jegharkraeft.dk\/en\/no-medicine-plan-b-2\/\">No medicine &#8211; Plan B<\/a><a href=\"https:\/\/jegharkraeft.dk\/en\/repurposed-drugs\/\"><\/a><\/p>\n\n\n\n<p class=\"has-custom-menu-links-color has-text-color has-link-color wp-elements-ef7d07e4a2f3fd4865240f3b1020f6b6 wp-block-paragraph\"><a href=\"#menu\">(to menu)<\/a><a href=\"https:\/\/jegharkraeft.dk\/en\/repurposed-drugs\/\"><\/a><\/p>\n\n\n\n<h4 class=\"wp-block-heading\">Links<\/h4>\n\n\n\n<p class=\"has-custom-sort-tekst-color has-text-color has-link-color wp-elements-c3ac134f004ec7798f09bf91e1e02e94 wp-block-paragraph\"><a href=\"https:\/\/www.interaktionsdatabasen.dk\/\" target=\"_blank\" rel=\"noopener\">Interactions (search for preparations)<\/a> (Interaktionsdatabasen, Danish Medicines Agency) (Danish Language)<\/p>\n\n\n\n<p class=\"has-custom-sort-tekst-color has-text-color has-link-color wp-elements-9e652d463e5c490681e09219a74f60e0 wp-block-paragraph\"><a href=\"https:\/\/www.ncbi.nlm.nih.gov\/pmc\/articles\/PMC8269327\/\" target=\"_blank\" rel=\"noreferrer noopener\">Antimicrobial Agents for Cancer Therapy<\/a> (PubMed)<\/p>\n\n\n\n<p class=\"has-custom-sort-tekst-color has-text-color has-link-color wp-elements-982b637f153eea51ed86a5c4a145ba49 wp-block-paragraph\"><a href=\"https:\/\/i2b.us\/repurposing-drugs-as-expanding-cancer-treatment-palette-doxycycline-as-a-cancer-treatment\/\" target=\"_blank\" rel=\"noreferrer noopener\">Doxycycline as a Cancer Treatment<\/a> (Omega Cancer Center)<\/p>\n\n\n\n<p class=\"has-custom-sort-tekst-color has-text-color has-link-color wp-elements-a54523589942d50f46541d996db68b86 wp-block-paragraph\"><a href=\"https:\/\/www.sciencedirect.com\/science\/article\/abs\/pii\/S0014299921007494\" target=\"_blank\" rel=\"noreferrer noopener\">Brief look at antitumor effects of doxycycline in the treatment of colorectal cancer<\/a> (Science Direct)<\/p>\n\n\n\n<p class=\"has-custom-sort-tekst-color has-text-color has-link-color wp-elements-1083ea44bd1be44e01c5bd4860c0f354 wp-block-paragraph\"><a href=\"https:\/\/www.ncbi.nlm.nih.gov\/pmc\/articles\/PMC5370004\/\" target=\"_blank\" rel=\"noreferrer noopener\">Doxycycline directly targets PAR1 to suppress tumor progression<\/a> (PubMed)<\/p>\n\n\n\n<p class=\"has-custom-sort-tekst-color has-text-color has-link-color wp-elements-9a758d8e6dabb1f9c9c32237dd291348 wp-block-paragraph\"><a href=\"https:\/\/www.ncbi.nlm.nih.gov\/pmc\/articles\/PMC5405729\/\" target=\"_blank\" rel=\"noreferrer noopener\">Doxycycline inhibits the cancer stem cell phenotype and epithelial-to-mesenchymal transition in breast cancer<\/a> (PubMed)<\/p>\n\n\n\n<p class=\"has-custom-sort-tekst-color has-text-color has-link-color wp-elements-a53fd26aae29003afb6b581adca590c6 wp-block-paragraph\"><a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/40273927\/\" target=\"_blank\" rel=\"noopener\">Matrix metalloproteinase 9 implication during colorectal carcinogenesis. Effect of doxycycline<\/a> (PubMed, 2025)<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li class=\"has-custom-sort-tekst-color has-text-color has-link-color wp-elements-f892a24cf31d6ec9faa8c42cb5b2cde7\"><strong>Content:<\/strong> Overexpression of MMP9 occurs early during colorectal carcinogenesis, and doxycycline can control the pathological conversion of the colonic mucosa into ACF clusters by decreasing MMP9 activity.<\/li>\n<\/ul>\n\n\n\n<p class=\"has-custom-sort-tekst-color has-text-color has-link-color wp-elements-14b7947eeec953be3f7f7b34f8fa6d28 wp-block-paragraph\"><a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/30364293\/\" target=\"_blank\" rel=\"noopener\">Doxycycline, an Inhibitor of Mitochondrial Biogenesis, Effectively Reduces Cancer Stem Cells (CSCs) in Early Breast Cancer Patients: A Clinical Pilot Study<\/a> (PubMed, 2018)<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Content:<\/strong> A pilot study in breast cancer patients shows that the antibiotic doxycycline appears to be able to eliminate aggressive cancer stem cells (CSCs). This was measured by a decrease in known stem cell markers (CD44 and ALDH1). Although results are promising, larger studies are needed to confirm the finding.<\/li>\n<\/ul>\n\n\n\n<p class=\"has-custom-sort-tekst-color has-text-color has-link-color wp-elements-29ff4603adb21c215a0a955e16e621db wp-block-paragraph\"><a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/31002656\/\" target=\"_blank\" rel=\"noopener\">Doxycycline, Azithromycin and Vitamin C (DAV): A potent combination therapy for targeting mitochondria and eradicating cancer stem cells (CSCs)<\/a> (PubMed, 2019)<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Content:<\/strong> A combination of two antibiotics (Doxycycline and Azithromycin) and Vitamin C acts as a &#8220;metabolic trap&#8221; that, in laboratory experiments, stopped over 90% of breast cancer stem cell growth by paralyzing their energy production.<\/li>\n<\/ul>\n\n\n\n<p class=\"has-custom-sort-tekst-color has-text-color has-link-color wp-elements-9ba9de8e67550f7ec01f7a5afdbd5092 wp-block-paragraph\"><a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/40284400\/\" target=\"_blank\" rel=\"noopener\">The Impact of Doxycycline as an Adjunctive Therapy on Prostate-Specific Antigen, Quality of Life, and Cognitive Function in Metastatic Prostate Cancer Patients: A Phase II Randomized Controlled Trial <\/a>(PubMed, 2025)<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Content:<\/strong> Doxycycline can help in metastatic prostate cancer by lowering PSA and improving quality of life. Further larger studies are needed to confirm this.<\/li>\n<\/ul>\n\n\n\n<p class=\"has-custom-sort-tekst-color has-text-color has-link-color wp-elements-291340763d6f523b82ce7120dc45872e wp-block-paragraph\"><a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/40465127\/\" target=\"_blank\" rel=\"noopener\">Impact of medications on the efficacy of immune checkpoint inhibitors in patients with recurrent or metastatic head and neck cancer<\/a> (PubMed, 2025)<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Content: Antibiotic treatment was associated with poorer survival in patients with RM-HNC receiving immunotherapy. This highlights the need for careful assessment of antibiotic use and the need for more research to improve treatment.<\/strong><\/li>\n<\/ul>\n\n\n\n<p class=\"has-custom-sort-tekst-color has-text-color has-link-color wp-elements-6deb6cbae7073198d6dd4c7ce26c115f wp-block-paragraph\"><a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/34644207\/\" target=\"_blank\" rel=\"noopener\">Doxycycline sensitizes renal cell carcinoma to chemotherapy by preferentially inhibiting mitochondrial translation<\/a> (PubMed, 2021)<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Content:<\/strong> This study shows that doxycycline can make kidney cancer cells more sensitive to chemotherapy. The mechanism is that doxycycline specifically inhibits the cancer cells&#8217; mitochondria (the cell&#8217;s power plants), which disrupts their energy production and makes them more vulnerable to the cell damage caused by the chemotherapy.<\/li>\n<\/ul>\n\n\n\n<p class=\"has-custom-sort-tekst-color has-text-color has-link-color wp-elements-9c1818be794023bb3036d3c0721c362e wp-block-paragraph\"><a href=\"https:\/\/www.mdpi.com\/1422-0067\/20\/1\/229\" target=\"_blank\" rel=\"noopener\">Targeting Mitochondria for Treatment of Chemoresistant Ovarian Cancer<\/a> (MDPI, 2019)<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Content:<\/strong> An article specifically describing how one can attack cancer cells&#8217; power plants (mitochondria) to fight resistant ovarian cancer \u2013 exactly the mechanism Doxycycline uses.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Page created:<\/strong> July 1, 2024, Last revised September 16, 2025<\/p>\n\n\n\n<p class=\"has-text-align-center wp-block-paragraph\"><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-custom-menu-links-color\">\u2764<\/mark><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong><em>What you read on Jeg har Kr\u00e6ft is not a recommendation. Seek competent guidance.<\/em><\/strong><\/p>\n<\/div>\n<\/div>\n<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_85 counter-hierarchy ez-toc-counter ez-toc-grey ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">Indhold<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"Toggle Table of Content\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><ul class='ez-toc-list-level-2' ><li class='ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/jegharkraeft.dk\/en\/doxycycline\/#Treatments\" >Treatments<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/jegharkraeft.dk\/en\/doxycycline\/#Complementary_and_Alternative_Treatments\" >Complementary and Alternative Treatments<\/a><\/li><\/ul><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-1'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/jegharkraeft.dk\/en\/doxycycline\/#Doxycycline_and_cancer\" >Doxycycline and cancer<\/a><ul class='ez-toc-list-level-2' ><li class='ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/jegharkraeft.dk\/en\/doxycycline\/#Important\" >Important<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/jegharkraeft.dk\/en\/doxycycline\/#Effect_and_Mechanism_of_Action\" >Effect and Mechanism of Action<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/jegharkraeft.dk\/en\/doxycycline\/#Adjuvant_Treatment\" >Adjuvant Treatment<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/jegharkraeft.dk\/en\/doxycycline\/#Side_Effects\" >Side Effects<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/jegharkraeft.dk\/en\/doxycycline\/#Note\" >Note<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-9\" href=\"https:\/\/jegharkraeft.dk\/en\/doxycycline\/#Conclusion\" >Conclusion<\/a><\/li><\/ul><\/li><\/ul><\/li><\/ul><\/nav><\/div>\n","protected":false},"excerpt":{"rendered":"<p>Treatments Complementary and Alternative Treatments Doxycycline and cancer Doxycycline is a broad-spectrum antibiotic primarily used to fight bacterial infections. However, in recent years, researchers have discovered that this substance may also have an interesting and promising effect on cancer cells. Therefore, doxycycline is being investigated as a potential adjuvant treatment\u2014a treatment used alongside other cancer [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":32979,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"inline_featured_image":false,"_lmt_disableupdate":"","_lmt_disable":"","footnotes":""},"categories":[393,375,374,396],"tags":[],"class_list":["post-32980","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-repurposed-drugs","category-alternative-treatments","category-treatments","category-immunomodulatory-agents"],"modified_by":"Hanne Kj\u00e6r Uhlig","wpml_current_locale":"en_US","wpml_translations":[],"_links":{"self":[{"href":"https:\/\/jegharkraeft.dk\/en\/wp-json\/wp\/v2\/posts\/32980","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/jegharkraeft.dk\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/jegharkraeft.dk\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/jegharkraeft.dk\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/jegharkraeft.dk\/en\/wp-json\/wp\/v2\/comments?post=32980"}],"version-history":[{"count":1,"href":"https:\/\/jegharkraeft.dk\/en\/wp-json\/wp\/v2\/posts\/32980\/revisions"}],"predecessor-version":[{"id":33826,"href":"https:\/\/jegharkraeft.dk\/en\/wp-json\/wp\/v2\/posts\/32980\/revisions\/33826"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/jegharkraeft.dk\/en\/wp-json\/wp\/v2\/media\/32979"}],"wp:attachment":[{"href":"https:\/\/jegharkraeft.dk\/en\/wp-json\/wp\/v2\/media?parent=32980"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/jegharkraeft.dk\/en\/wp-json\/wp\/v2\/categories?post=32980"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/jegharkraeft.dk\/en\/wp-json\/wp\/v2\/tags?post=32980"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}