Pharmaceutical companies invest enormous resources into trials before any drug reaches the public. This careful process aims to prevent disasters like the thalidomide tragedy in the 1950s and ’60s, which led to severe birth defects in thousands of children. Authorities now meticulously oversee drug development to ensure safety and inform users about potential side effects.
However, knowing a drug is effective isn’t the same as understanding its precise mechanism. The human body is incredibly complex, and many aspects remain a puzzle. Here are 10 medicines that effectively treat various conditions, yet their exact workings are still largely a mystery.
10 Abatacept
Abatacept, often sold under the brand name Orencia, is typically prescribed for conditions like rheumatoid arthritis. Its mysterious capabilities came to light in a striking case reported by Science magazine in 2015. A 12-year-old boy with a rare genetic disease suffered from a faulty immune system that attacked his lungs and intestines. He had been ill for years.
When doctors considered a bone marrow transplant, they deemed him too sick. As a palliative measure, they administered Abatacept, not expecting a cure but perhaps some pain relief. To everyone’s surprise, the boy returned six months later in significantly better health. Why Abatacept worked so effectively in this unique case remains an puzzle.
9 Tylenol
Tylenol, or acetaminophen, is a staple in many American households for pain relief. It’s considered safe when taken as directed, but how it actually works is not definitively known. Scientists have several theories:
- It might inhibit an enzyme responsible for the sensation of pain.
- It could be interacting with the endocannabinoid system, similar to how THC in marijuana provides pain relief.
- It may affect signals from serotonin, a neurotransmitter crucial for many cognitive functions.
It’s possible that Tylenol employs a combination of these mechanisms, or perhaps another entirely different pathway is at play.
8 Lithium
Lithium, available under brand names like Eskalith and Lithobid, is a widely recognized and effective treatment for bipolar disorder. This lifelong condition causes extreme mood swings, from deep depression to intense euphoria. Lithium can lessen the severity and frequency of manic episodes and reduce suicide risk during depressive states.
While we know lithium impacts the central nervous system, its precise actions are unclear. It might strengthen brain connections that regulate mood and behavior, thereby stabilizing the system. Interestingly, lithium, the same element used in batteries, is present in tiny amounts in biological systems, though its natural role is also a mystery.
7 Ulipristal
Ulipristal, marketed as Esmya, is an emergency contraceptive used after unprotected intercourse or contraceptive failure. It’s known to prevent or delay ovulation. However, it might also alter the uterine lining. Although effective, the complete mechanism behind its action isn’t fully understood.
This medication should be taken within five days of unprotected sex and is only for this specific circumstance. It’s important to remember that ulipristal offers no protection against sexually transmitted diseases.
6 Paxlovid
During the rush to find effective treatments for COVID-19, Pfizer announced in November 2021 that their drug, Paxlovid, could reduce hospitalization rates by nearly 90%. Clinical trials confirmed its safety, but questions about its mechanism lingered. Paxlovid inhibits a viral enzyme crucial for the development of viral proteins into their active, harmful state.
By stopping this enzyme, the virus’s development is halted. However, exactly how Paxlovid achieves this disruption in viral replication isn’t completely clear. Paxlovid also contains ritonavir, a drug that can interfere with how the body processes other medications, making it crucial for patients to inform their doctors about any other drugs they are taking.
5 Valdecoxib
Valdecoxib, sold as Bextra, was a popular treatment for rheumatoid arthritis and similar conditions. It belongs to a class of NSAIDs called COX-2 inhibitors and was designed to stop the body’s production of substances causing pain and inflammation. While it worked, its mechanism had broader and unexpected effects compared to other COX-2 inhibitors.
In 2005, the FDA withdrew it from the market because its risks, including heart, skin, and stomach problems, outweighed its benefits. This case highlights that even after extensive trials, the full range of a drug’s effects and how it truly works can take years to emerge.
4 Febuxostat
Gout, a severely painful condition caused by excess uric acid forming crystals around joints, can be treated long-term with Febuxostat (brand name Uloric, among others). This drug reduces uric acid production and is often prescribed when patients cannot tolerate allopurinol. While Febuxostat is effective against gout, it’s less clear why some individuals experience severe side effects.
These side effects can range from liver issues, joint pain, and nausea to skin rashes, and in rare instances, life-threatening anaphylactic shock. The precise reasons for these varied reactions aren’t fully understood.
3 Tofacitinib
Tofacitinib, commonly sold as Xeljanz, is another medicine that didn’t work exactly as its developers initially anticipated. It’s often prescribed for rheumatoid arthritis patients who cannot tolerate the more common drug, Methotrexate. Approved by the FDA in 2012 after years of trials, initial side effects included upper respiratory tract infections, diarrhea, and headaches.
Then, a 2014 study revealed an unexpected effect: tofacitinib converted white fat tissues into more active brown fat tissues, which break down more easily. This suggested potential as an obesity treatment, but also highlighted that researchers didn’t fully grasp its workings. Some patients have rarely experienced serious side effects like cancer or pulmonary embolisms.
2 Paroxetine
Known by brand names like Seroxat or Paxil, Paroxetine is an antidepressant. Doctors also prescribe it for obsessive-compulsive disorder, panic attacks, post-traumatic stress, and social anxiety. It’s even used for premature ejaculation and menopausal hot flashes. Paroxetine is a selective serotonin reuptake inhibitor (SSRI).
While this name suggests scientists know what it does, the understanding is incomplete. They know it’s effective, but the ‘why’ is elusive. The leading theory is that it increases serotonin levels in the brain. However, since the complex functions of serotonin itself—affecting mood, cognition, learning, and memory—aren’t fully understood, the precise mechanism of paroxetine remains a question.
1 Aspirin
Aspirin, a long-standing painkiller, saw a dip in popularity in the 1960s with the advent of other analgesics. However, its reputation revived when scientists discovered it was also a potent blood thinner, capable of reducing the risk of heart attacks and strokes. Some doctors now recommend regular low-dose aspirin, though opinions vary.
More recently, Swedish research uncovered another potential benefit. Analyzing data from 80,000 cancer patients, they found that individuals with colon or lung cancer who had regularly taken low-strength aspirin before their diagnosis tended to have less advanced tumors. The reason for this correlation is still being investigated, but it might be linked to aspirin’s anti-inflammatory properties slowing DNA damage that can lead to cancer. The full story of how aspirin achieves its diverse effects is still unfolding.
These examples remind us that while modern medicine has achieved incredible feats, there’s still so much to learn about the intricate workings of the human body and the drugs we use to heal it. The quest for understanding continues, promising even more targeted and effective treatments in the future.
Which of these medical mysteries surprised you the most? Do you know of other medicines with unexplained mechanisms? Share your thoughts in the comments below!
