The Rise and Fall of Colistin: Understanding the Antibiotic's Short Reign

Antibiotics are one of the most significant discoveries in medical history. They have saved countless lives and revolutionized modern medicine as we know it today. Among these antibiotics is colistin, which gained popularity for its effectiveness against drug-resistant bacteria. However, despite being hailed as a game-changer in healthcare, colistin's reign was short-lived. In this blog post, we will delve into the rise and fall of colistin - understanding its benefits, side effects, why it was discontinued, and what alternatives exist for medical professionals to consider when treating their patients' bacterial infections.

How did colistin come to be used as an antibiotic?

The story of colistin as an antibiotic began in the 1940s when it was first discovered by Japanese scientists. Initially, it was used for topical treatments and later on for treating gastrointestinal infections. Colistin is a type of polymyxin that works by damaging the bacterial cell membrane leading to cell death.

Over time, however, antibiotics became more widespread and drug-resistant bacteria started emerging. In response to this growing problem, researchers revisited colistin's potential as an antibiotic in the late 1990s.

Studies showed that colistin could effectively treat multi-drug resistant bacteria such as Acinetobacter baumannii and Pseudomonas aeruginosa, making it a valuable option for patients with limited treatment options.

Despite its efficacy against drug-resistant bacteria, concerns were raised about its toxicity levels. Colistin can cause severe kidney damage especially when given intravenously at high doses over prolonged periods.

What are the side effects of colistin?

Colistin is known to be a potent antibiotic that can combat multidrug-resistant bacteria. However, like any medication, it comes with side effects. One of the most common side effects of colistin is nephrotoxicity or kidney damage. This adverse reaction occurs more frequently in patients who are already suffering from renal problems.

Another possible side effect of colistin is neurotoxicity which affects the central nervous system and could lead to seizures, confusion, and muscle weakness. It's also worth noting that prolonged usage of nebulized colistin has been linked to bronchospasms in some cases.

In rare instances, colistin may cause liver damage resulting in elevated liver enzymes levels and jaundice-like symptoms such as yellowing skin or eyes.

Apart from these physical concerns, there have been reports about psychological impacts associated with taking this drug too. Cases of depression and anxiety have been reported among patients who were prescribed nebulized colistin for an extended period due to chronic respiratory diseases.

Why was colistin discontinued as an antibiotic?

Colistin, also known as polymyxin E, was initially used in the 1950s to treat infections caused by Gram-negative bacteria. However, due to its nephrotoxic and neurotoxic side effects, it was discontinued as a first-line antibiotic therapy. 

After years of limited use, colistin regained popularity in the early 2000s due to the emergence of multidrug-resistant bacteria such as Pseudomonas aeruginosa and Acinetobacter baumannii. The World Health Organization (WHO) listed colistin on their Essential Medicines List for humans in 2017.

Unfortunately, overuse and misuse of colistin led to bacterial resistance against this last-resort antibiotic. This is because unlike other antibiotics that target a specific part of the bacterial cell wall or protein synthesis, colistin attacks and breaks down the outer membrane of Gram-negative bacteria.

As a result, medical professionals started seeing an increase in cases where patients with multidrug-resistant infections were no longer responding positively to treatment with nebulized colistin or intravenous administration. Consequently, health authorities had to issue guidelines limiting its use only when necessary.

What are the alternatives to colistin?

As the use of colistin as an antibiotic becomes increasingly limited, healthcare professionals must explore alternative treatment options.

One option is to use combination therapy, where two or more antibiotics are used together to increase their effectiveness against bacteria. This approach has shown promise in treating infections caused by multidrug-resistant organisms.

Another option is the use of new-generation antibiotics such as ceftazidime-avibactam and meropenem-vaborbactam, which have been approved for the treatment of complicated urinary tract and intra-abdominal infections. These newer drugs offer a much-needed solution for patients who have developed resistance to older antibiotics.

In addition, strategies that focus on preventing infection through improved hygiene practices and appropriate antibiotic prescribing can also help reduce the need for colistin or other last-resort antibiotics. For example, hand hygiene campaigns in hospitals have been shown to significantly reduce rates of infection.

Conclusion

Colistin was once a powerful antibiotic that saved countless lives. However, due to its harmful side effects and the emergence of resistant strains, it has fallen out of use as a first-line treatment option. While there are still cases where colistin may be necessary, medical professionals should consider alternative treatments whenever possible.

It is important for healthcare providers to stay informed about new developments in antibiotic research and continue to work towards finding effective solutions for bacterial infections. By being mindful of prescribing practices and utilizing other treatment options when appropriate, we can help slow the spread of antibiotic resistance and ensure that our patients receive the best possible care.