Minocycline and Doxycycline are both second-generation tetracycline-class antibiotics. They both are approved by the Food and Drug Administration (FDA) and have been proven effective for the treatment of acne, also known as acne vulgaris, but what else is there to know about them? Here are some of the main similarities and differences between minocycline and doxycycline.
How are Minocycline and Doxycycline Similar?
As previously mentioned, minocycline and doxycycline are both second-generation tetracycline antibiotics. This means they are both slightly modified versions of the naturally occurring parent chemical. Interestingly, both are extremely well-absorbed by the body and have similar elimination half-lives, an indication of how long it takes the body to process and remove the drug after it is taken or administered.
You can get either product in tablet and capsule form, though the cost can vary depending on the strength and type of dose.
Additionally, the absorption of both doxycycline and minocycline can be affected by taking them at the same time as dairy products, vitamins, or antacids, all of which contain divalent or trivalent cations, positive ions with a charge of 2 or 3.
Minocycline and doxycycline share many of the same side effects, mostly localized to the digestive tract; namely nausea, diarrhea, loose stool, vomiting, and photosensitive, or extra sensitive to sunlight. It should also be noted that both can interfere with the effectiveness of birth control pills too. Pregnant women or women who are breastfeeding are also advised against taking both drugs unless instructed by a physician.
Both medications have a similar spectrum of bacteria they are effective at treating, including gram-negative and gram-positive bacteria, as well as bacteria that cause some rarer bacterial infections like those that cause lung or respiratory tract infections, sexually transmitted infections, plague, anthrax, and bacteria that are commonly transmitted from infected soil and animals.
Doxycycline and minocycline show similar efficacy with no significant difference in treating moderate to severe acne in patients that are usually dosed twice daily, and share some side effects which we listed above.
While they use slightly different mechanisms to inhibit angiogenesis or the creation of new blood vessels, both medications are effective at inhibition, assisting with some cardiovascular conditions and having implications for cancer and tumor growth.
While they are not equally effective across all types of pain sensation, both doxycycline and minocycline are effective at reducing and treating pain from a variety of causes.
How are Minocycline and Doxycycline Different?
Minocycline and doxycycline differ in many ways, but the easiest way to consider them is to look at the unique advantages of each. Below are examples of the advantages noted for each specific medication.
What Advantages Does Minocycline Have?
Minocycline is 10 times more potent than doxycycline as an antioxidant, or free radical scavenger. As a result, it is more effective at preventing oxidative damage, especially in the case of nerves and brain tissue.
MRSA and other resistant bacteria
Minocycline has been proven to be more effective than doxycycline in treating methicillin-resistant staph. aureus, or MRSA, infections. While doxycycline can successfully inhibit infection growth and spreading, it is not usually successful at clearing the infection. Minocycline, however, successfully clears the infection quickly.
Minocycline is also more effective at treating vancomycin-resistant enterococcus (VRE) and Acinetobacter species.
Minocycline is also slightly more lipophilic than doxycycline. This means that it distributes better into the tissue, as opposed to a hydrophilic medication, which would distribute better into fluids like blood. Because it has better tissue penetration, minocycline is a better treatment option for some infection types based on their location.
Similarly, because of its lipophilicity, minocycline also is able to cross the blood-brain barrier, which allows for some of the neuroprotective effects seen on the brain, spinal cord, and nerves. This also makes it a better candidate to treat infections in the central nervous system, as it can get where it is needed.
What Advantages Does Doxycycline Have?
Unlike minocycline, doxycycline does not bind strongly to calcium or discolor teeth, skin, and other tissue. It also has a milder side effect profile. For this reason, doxycycline is not only approved for use in children, but also comes in a kid-friendly liquid, or reconstitutable, formulation.
Between the two drugs, doxycycline is the more potent anti-inflammatory agent over minocycline. This is due to both the mechanism of how doxycycline addresses inflammation, as well as the fact that inflammation is typically higher accompanied by fluid retention, which allows for greater concentrations of the more hydrophilic doxycycline molecules.
While both medications have some pain-alleviating properties, doxycycline performs better at pain treatment and prevention, and often at lower doses than those needed with minocycline.
First, despite being prescribed an average of 3 times more often than minocycline, doxycycline is 5.5 times less likely to cause adverse effects. This may be partially due to the fact that doxycycline prescriptions are shorter, on average, than minocycline prescriptions; there simply may not have been enough time for side effects to develop. However, this most likely can be tied to the fact that doxycycline has a much smaller side effect profile than minocycline.
In fact, the most common side effects in people taking doxycycline are in the digestive tract, and most can be minimized by taking it with a meal (there are some food restrictions). Minocycline, however, is known to also cause digestive tract side effects, in addition to potentially irreversible skin discoloration, dizziness and lightheadedness, and some auto-immune related conditions.
Like all antibiotics, both minocycline and doxycycline require a prescription from a health care provider in the United States. For more information about either medication or how the two compare, take a look at these articles or consult with a health care provider.
References and Sources
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Cunha BA, Baron J, Cunha CB. Similarities and differences between doxycycline and minocycline: clinical and antimicrobial stewardship considerations. European Journal of Clinical Microbiology & Infectious Diseases. 2018/01/01 2018;37(1):15-20. doi:10.1007/s10096-017-3081-x
Gaillard T, Briolant S, Madamet M, Pradines B. The end of a dogma: the safety of doxycycline use in young children for malaria treatment. Malaria journal. 2017;16(1):148-148. doi:10.1186/s12936-017-1797-9
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Saivin S, Houin G. Clinical Pharmacokinetics of Doxycycline and Minocycline. Clinical Pharmacokinetics. 1988/12/01 1988;15(6):355-366. doi:10.2165/00003088-198815060- 00001
Sapadin AN, Fleischmajer R. Tetracyclines: nonantibiotic properties and their clinical implications. J Am Acad Dermatol. Feb 2006;54(2):258-65. doi:10.1016/j.jaad.2005.10.004
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