How does medication know where exactly the pain in my body is?

When you miss a step and fall, resulting in excruciating pain in your knee… you take a painkiller. When you accidentally cut your finger while making dinner… you take a painkiller. When you have an inexplicable headache… you take a painkiller. How do these pain killers seem to work in all of these areas of the body? How does the medication know where the pain is? Pharmacology, a branch of medicine that focuses on studying the uses, effects and mechanisms of action of drugs, helps in providing answers to such questions.

So, here goes… When you swallow a painkiller, it dissolves in the stomach or sometimes the small intestines before it is absorbed into the whole body. Pills are not smart enough to only travel to the place where their action is required. However, the secret to the function of painkillers depends on the mechanism with which pain is mediated in the human body.

When one is injured, cells release molecules called prostaglandins, and nerve endings are sensitive to these prostaglandins. Following prostaglandin release, nerves then transmit signals to the brain communicate the intensity and site of the pain. It would make sense then to reduce the synthesis of prostaglandins to stop transmission of the pain signals, right? This is exactly how pain relievers like aspirin work. They are distributed throughout the body, and reduce prostaglandin synthesis, reducing the transmission of pain signals.

Therefore, a painkiller does not know where the pain actually is, but it works by reducing prostaglandin synthesis in areas where there high levels of production of these chemical mediators of pain, resulting in relief.

However, since the drug travels throughout the whole body, it could potentially work where it is not supposed to, and this unfortunately results in side effects. Regarding pain reduction, prostaglandins are not only released in injured cells, but specific types of prostaglandins are constantly produced by the body for the maintenance of normal bodily functions. As shown in the figure below.

Reduction of the prostaglandins needed for normal bodily functions leads to various side effects. For example, the use of pain killers may result in the loss of prostaglandins needed for protection of the stomach, leading to stomach ulcers. Fortunately, prior to the use of drugs, clinical trials are typically conducted to investigate that any side effects are not detrimental to life.

The phenomenon of how drugs work is not only limited to painkillers. Although many drugs are distributed throughout the body, their main action is based on correcting the abnormalities that occur in the biology of various diseases. For example, many anti-cancer drugs work by targeting cells that grow at a fast rate. Though the medication will kill the fast-growing cancer cells, it will also result in the loss of healthy cells that grow fast, like hair follicles, leading to side effects like hair loss. Therefore, when taking any type of medication, one should keep in mind that the distribution of drugs in the body could result in undesired side effects, and overuse of over-the-counter medications should thus be avoided.

Images created using icons adapted from

Science and Sustainability

One of the most impactful discoveries in science over the past century is the discovery that the Earth’s climate is changing on a catastrophic scale due to the release of man-made greenhouse gasses. This topic has been on everyone’s mind recently, thanks to the efforts of activist Greta Thunberg and many others. It got me thinking about how science – which helped the world realise there is a major problem – could do a lot better in terms of being environmentally-friendly. I also came across this article, which discussed the issue with plastic waste in certain fields.

Since this is a platform for young scientists, and young people are often open to change and trying out new things, I thought it would be a good place to open up the discussion about what we can do to reduce the environmental impact of our science. I know that most of us, as postgrads and young researchers, don’t necessarily have the power or authority to implement changes on the large scale as needed – and may require participating in some of the more destructive habits like travel to build our careers – but we can start by raising these topics and making suggestions! I’d also like to remind everyone that no-one is perfect when it comes to being carbon-neutral, but it’s important that we all try our best for the sake of the planet!

polar ice cracking (credit: By Christopher Michel –, CC BY 2.0,,

Since I’m an astronomer, I will be drawing from this white paper titled ‘Astronomy in a Low Carbon Future’, which was prepared for Canada’s long-term planning in astronomy. Because of this, not all of this advice will be applicable in other fields. I’m looking forward to reading the comments on how some of these strategies could be adapted to other fields and how other fields have their own challenges and possibilities. 

One of the first, most impactful ways for science to reduce its carbon budget is to reduce travel. Between conferences and fieldwork, travel is an important and valuable part of science. However, air travel produces excessive amounts of carbon dioxide. Travel can be reduced by moving to remote meetings, conferences and even – in some cases – fieldwork. I recently took part in a meeting with and presented my work to some important collaborators in North Carolina without having to leave Cape Town, since the conference organisers wholeheartedly embraced remote participation through Zoom and Google Slides. It also made my participation possible, since I do not have much funding for travel and would not have been able to physically attend the conference otherwise. Although I missed out on the informal discussions, I was still able to confidently present my work and discuss some collaborative research that will form part of my Masters.

Another way that astronomy, in particular, is able to reduce travel is through remote observing. One of my fellow Masters’ students here at the South African Astronomical Observatory regularly controls a telescope in Sutherland from Cape Town and collects her astronomical data without having to travel. Remote observing is slowly becoming more common, which is excellent for reducing the amount of travel that observational astronomers have to do. 

1.9m telescope in Sutherland which is remotely operable (Credit: SAAO)

An easy substitution that will reduce waste and greenhouse gas emissions is through catering at events. Switching to meals that are vegetarian for the most part will help cut down on overall meat consumption. The other plus-side to this is that it will make everyone who already eats vegetarian food a lot happier since their meals won’t be a sad, salad-based afterthought. 

Since the electricity supply in South Africa is currently a coal-based disaster, this is an area that gives me very little hope when it comes to powering scientific equipment and instrumentation. Unfortunately, massive telescopes like MeerKAT and the upcoming SKA require a lot of power. I can only hope that these telescopes will be powered through the abundant Karoo sunshine, rather than more coal. But, with Eskom’s current crisis and the relatively cheap price of coal, that seems less and less likely. As a student, I don’t have any insight into how the climate effects of this might be mitigated, but it is something that I would like to raise when I get the opportunity to do so.

Lastly, I think it’s important that – as scientists – we take part in political processes to counter climate change. Since none of our major political parties seems to take climate change as seriously as they should, we should make our voices heard by supporting activist groups that have the expertise necessary to put climate change on the government’s agenda. On a smaller scale, we can support organisations on our own campuses that advocate for the fight against climate change. Although individual efforts are important, this is a global problem that requires governmental and institutional interventions to prevent the catastrophic effects that will hit countries like South Africa the hardest.