Clinical trials & medical research (young people)

Side effects when taking part in trials

Clinical trials are carefully designed to be as safe as possible for everyone taking part, whichever treatment they receive. Some trials will involve very little risk. In others there may be some side effects from treatments, and finding out more about these side effects is one of the reasons we have trials. Researchers should explain to you what they already know about possible side effects to help you decide whether or not you want to take part. This will depend very much on the type of treatment being tested, so you will need to ask questions about the specific trial. Of course, it can be worrying hearing about all the possible side effects. However, it is important to bear in mind that not everyone will experience them. It is also important to remember that some side effects may just be the result of treatment (such as chemotherapy for cancer) and not specifically because of the trial.

Most young people we talked to said that possible known side effects of treatment were explained to them and they were able to ask questions and raise any concerns. (See also ‘Being invited to take part in a clinical trial: information and questions’.)


Kay knew what the side effects might be and what to do if she experienced any, but in fact she...

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Age at interview: 23
Sex: Female
Is it nicer than the Mannitol?
It’s nicer in a way that I don’t have to take as many capsules. But if I was given a choice between, I don’t know actually I like both of the medications, I probably would go for the Heparin just because it’s only got four capsules whereas the other one’s got ten capsules and I didn’t mind ten capsules but I can imagine some people thinking that’s quite a lot to do in one, in one go.
But no, but what I thinks’ really good I get paid £70.00 for each time that I go to the study which I’m benefitting from the medication anyway. They put my clinic appointments in with my study appointments. So I don’t have to go to the hospital any more than I would be and I obviously get paid and it’s helping my chest like it’s really really good so.
So it’s beneficial?
Beneficial in a lot of ways so
I’m happy to be to be on it.
And this is just a straight, the other one was like a double blind trial, this one’s a straight forward?
No. It’s the same. You’ve got placebo and three other different strengths so it’s the same sort of chances of the Mannitol. But the way I’ve reacted to this medication I think I’m on some level of Heparin , I don’t know what dosage, but the way I’ve reacted I think I am.



Although Graham experienced some side effects, he wasn’t shocked because everything had been...

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Age at interview: 16
Sex: Male
Age at diagnosis: 16
And did they mention about any side effects at all?
Yes, when I started all the treatment they explained it all, like what kinds of things can happen like hair loss and stuff and all different, they made it easy to understand. So what to expect, won’t be shocked.
And did you have any questions at that point? Was there anything that, you know, worried you at the time?
No, not really because I sort of expected all the things like.
They were what you expected anyway?
Yes, like I thought about, about hair loss and all that, but I wasn’t really bothered.
Was there anything else? I mean have you experienced, apart from the hair loss, have you experienced anything, any other side effects in relation to…?
I’ve had bad cramps like with the, with the steroids and bad back, pain in my legs and stuff. But they give you painkillers to monitor it, so you’re okay.
They give you more pills?
But were you concerned when you were getting those? I mean were they clearly explained that you might get cramps?
Yes, yes. They explained all the stuff that could happen and then they told us how they’d try and stop it and stuff and get rid of it if it happens.
So can you tell me, can you remember what the side effects were?
Of the, when you were in the trial aspects of the treatment and the drugs that you were taking or are taking.
I think, you have vincristine which is chemotherapy and it can make your, all your joints ache, like your knees and your back and stuff. And it’s very painful, but they give you like painkillers for that. And the steroids can just like make you constipated and stuff and give you, yes, I think it’s mainly the one from the steroids make you constipated. And they give you more pills to get rid of that.
Like a laxative type thing?
And that’s about it really from the chemotherapy.
And you’ve had, you’ve had all of those things that they’ve said?
And how does it feel going through, you know, in, with all those side effects as well?
If you take the tablets they give you and stuff and, it doesn’t seem to be as bad, like they get rid of it pretty quickly. But can make you feel pretty bad, then you’ve got bad head and like and backache.


However, others felt that information they had received at the start of the trial ‘downplayed’ some of the side effects they experienced during the trial. 


Even though Stephanie experienced quite a few side effects from the trial drug, she was pleased...

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Age at interview: 18
Sex: Female
Age at diagnosis: 15
And how long did the side effects last?
The side effects lasted, well, I was, I was sick and nauseous [door] throughout the whole thing. But the kind of bruising and the cutting kind of went down after about maybe two months of eighteen months.
And are you pleased to have taken part?
Yes, I am. I feel like, I feel like I’ve had a much easier road to, a road to recovery than I could have had, done. And I think that even though the side effects were bad, they weren’t as bad as they could have been. I’m quite lucky that I’ve been, like it was just return to my life as I would have done. Maybe feeling a bit different but, you know, just being a normal kind of teenager and just getting on with it.


Of course health professionals do not want to scare people about rare side effects that may never happen, but Katie pointed out it can actually be reassuring to know about all known side effects.


Even though Katie did not really experience any side effects she was glad to know what they might...

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Age at interview: 13
Sex: Female
Was that reassuring for you, yes? And did they explain about any side effects to you at the time?
Yes they said one of them might be a bit of a rash and they said a couple of other ones. So it was quite reassuring knowing that if I was going to get something then I would know it was that, it wasn’t something else.
Okay so it was good to know that, the side effects, do you think it’s important that they told you about that.
And did you have any questions at all?
I think they pretty much summed it all up in the information.
Was you quite concerned about anything at all?
No not really.


One of the main reasons for carrying out trials is to find out about side effects and measure how serious they are. Young people who take part in trials are monitored carefully. They will often require regular tests and may be asked questions about how they feel. 


Jenna experienced some side effects from the trial drug, but they didn’t last long and she always...

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Age at interview: 13
Sex: Female
Age at diagnosis: 11
And did they say what the side effects might be?
Jenna' I can’t really remember, but I think they did say some. But I do remember that rashes were some like common ones.
Were they?
Jenna' Like dry skin.
Have you had any of them?
Jenna' Yes.
Have you?
Jenna' It was just like a bit of eczema type stuff, like under my eyes.
What did you do, what happened when you had, started to get some of the side effects?
Jenna' Well, when I got dry skin I just used a moisturiser. It, it like went away. I just have to keep putting it on. Because like when I wash my face it feels a bit dry, so I just put some on.
What were the other side effects?
Jenna' I can’t remember.
Mum' Stomach ache.
Jenna' Yes, stomach ache after it. But that, I don’t really, that doesn’t really happen anymore.
Mum' No, it only happened for the first few times and then I think her body got used to it.
So you did have a bit of, so you’ve had one or two…
Jenna' Yes.
…reactions then? But they’ve eased off a little bit?
Jenna' Yes.
Did it worry, you know, when they, when you did get the stomach pains and the dry skin, did it, did it worry you at all?
Jenna' Not really.
Why was that?
Jenna' Because like it was just a stomach ache and it, like it went quite quickly sort of. So I didn’t really think it was that bad.
It wasn’t like a, what sort of a pain, was it a?
Jenna' It was sort of like a stitch, but like just in my lower stomach.
Just a bit of a niggly pain? Did it, you know, did it, was it like last a long time or did it go away quite quickly?
Jenna' About twenty minutes or something probably.
And that was soon after you’d, soon after you’d had the drip? Was that soon afterwards?
Jenna' Like a day or something, a couple of days.
Mum' She would complain on and off for a couple of days maybe after the treatment. It would come and go, wouldn’t it?
Jenna' Yes.
So it was doing, it was obviously doing something to make you just feel a little bit out of sorts. You didn’t feel, did you feel a need to ring the hospital at all?
Jenna' No, but like they ask us if we’ve had any side effects or like any, like if we’ve felt sick or if we’ve had any colds or anything, so they can like write it down. So my mum told them when we went.
And do you have to report like every time you go and have your drip, your cannula and you have your drip and you’re going for the day or half day?



Taking a different type of insulin was painful for Lauren at the start of the trial, but she got...

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Age at interview: 16
Sex: Female
Age at diagnosis: 13
Did they say what the side effects were?
No. That’s what they were trying, they, they didn’t say that there’d be like massive side effects, there were side effects. They were thinking that there could be, there’s possible weight gain and there was a couple of others, but I can’t remember what they were. But they said they just wanted to see whether we put on weight or whether we didn’t or if we lose, lost it because of this background insulin. But they said they didn’t think any others; there was any other side effects except weight gain and I think something else. But I can’t remember at all what that was.
And have you had any side effects, do you know?
I’ve put on weight. But that’s about it, yes.
And do you have to tell them that? Do they weigh you at all?
They weigh me, do my blood pressure, measure me, take my height. And that’s about it really.
And is that every time you go?
Yes, every…
For the three-monthly?
Yes. But I never have to do it when I go up the hospital because they normally send the results that have already been taken. So it’s not bad.
And you said there was more pain I think…?
Yes, my, the insulin that I’m taking, Lantus, I find is a lot more painful. And it’s also because I’ve got a small needle. I use a 4 millimetre needle instead of a 5 millimetre needle because I don’t like them. They hurt so much. But a 4 millimetre is nicer. But with the Lantus it stings so much more. And it’s just like, “Waiting for the pain to go now.”
So that’s when you’re actually giving yourself the injection?
It’s more painful?
And then afterwards it stings a bit and it’s just like… And then you kind of question whether you really want to carry on. Then you’re like, “No. I will do it. I am fine with it.” And then you tell them and they’re, and they’re like, they say, “Well, do you want to drop out? Because you can. You’re more than welcome to drop out if you want, if you don’t want to do it anymore and we’ll put you back on.” But I’m all right with it after I’ve done it. It’s getting to the stage of doing it. But now it’s been down to 26, although it’s only four units lower than 30, it’s so much nicer. But, not much nicer, but it feels nicer.


It is important to report any side effects promptly as this tells the researchers something important about treatments being tested. They will be able to help manage the side effects, or advise you whether you should stop taking part. Some of these may be new side effects that were not expected. 

Alexander, aged 18, talks about his experience of taking part in a randomised placebo controlled trial on a new treatment for arthritis. When he first took part he had problems sleeping, which turned out to be a new side effect. 


Doctors and patients need to exchange information about any new side effects and you may need to...

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Age at interview: 18
Sex: Male
Age at diagnosis: 16
But luckily, as I said earlier, they just kind of said, “No, we can move you in to the third extension.”
And that’s what you did?
And you had to sign some more forms?
Did it worry you, having to keep signing these forms?
I’d say a little bit, for the pure fact of you have to, you have to know what you’re signing in to. You didn’t really want to just kind of sign willy-nilly. Just, so looking for what you have to worry about, what’s new on this form. Because the forms look pretty much identical. There may be like five new words or a new paragraph you have to look for to say what this new bit is. So that’s a bit weird.
Did they not explain that to you?
They did, but not extremely well. They just kind of went, “Here’s the paperwork. It’s not really that, not really that important. You’ve probably had it.” Like the sleep deprivation, that was like three paragraphs long, that was quite easy to spot. But then the skin splitting, that went down to a paragraph because lots of other people had experienced it too. So it was kind of, you had to push it down and down and down.
And were there any new side effects?
The new side effects were sleep deprivation was the new one, the new one. The skin wasn’t really new. I think it’s because if you’ve ever had like a skin condition like eczema or something, your skin is obviously going to be weaker, so they had to kind of develop around that. So that could have been something they had to worry about. There’s something else, another medical, I can’t remember what it’s called, but it’s something where your body literally repels itself and it causes high temperatures. Luckily enough I haven’t had that. But that’s something what’s recently come out. And I think it’s called mus or mos or something.
And they have to let you know about that?
They have to let you know, and this, and things like that the doctors will actually come and tell you clearly and simply. So they tell you, “If you look out and find these symptoms, come back and tell us straight away.”


Because neither Alexander nor the doctors and those involved in his care know which drug he is taking, it was sometimes a bit worrying. 


Soon after starting one stage of the trial Alexander noticed his arthritis symptoms getting worse...

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Age at interview: 18
Sex: Male
Age at diagnosis: 16
The second part, the second extension is for six months. And it’s, once again once every month you go back to the hospital and they give you a dose. But how, this time it’s a randomised drug test. So it could be a placebo or you could be having the real thing. I think the, just to see if the drug actually works or if it’s in the mind or if it doesn’t do anything for you. It’s once again just a kind of experiment. But I only did that for about three to four months. And I was pretty sure I was on the placebo for the pure fact of my joints were getting worse and the kind of salmon-coloured rash was coming out again.

Did it make it worse or was it something new?
It was there before any of the medication, when I was on this medication. It does calm down but it sometimes still flares up. However this was, it flared up to how it used to be. It would cover my arms, legs, hands, anything. So that was kind of a, kind of an insurance, going, “Yes, maybe it’s not, you’re not on the drug any more, you’re on the placebo.” But how, because it was a double blind and I was no medical kind of worry, they didn’t take me off it. So, but after the third or fourth month they decided to call-up, because I was getting worse, but my bloods weren’t showing anything. And me and my mum went for lunch thinking, “Do I come off the drug? Do I stay on it?” So that was a good couple of hours, a little chat. And then came up to the ward again to say, “No, we don’t need, you don’t need to worry about this anymore. We can put you in to the third extension straight away, where you‘re guaranteed the drug.” But it’s for a long period of time. I think it’s for about two and a half years, to see if the drug was having any long-term side effects and that kind of stuff.

I noticed I could actually go to sleep without these pills. And it was it was quite obvious that I was starting to go back in to kind of my old ways. My skin was starting to flare up with the rash. I was getting, temperatures were going up higher and my joints were getting definitely a lot stiffer and harder to move. So that was a bit frustrating, knowing I’m on this but they can’t do anything for me for six months because of mmm. The first month it wasn’t so bad. I was learning to just go, “Oh, yes, I’m getting a bit tired, a bit stiff. My arms are getting a bit sore, itchy.” I think that could just be maybe one of the, the kind of irritation where the skin splits, going, “Okay, I can live with that again.” And then the second month I noticed I w-, didn’t have like the flu-like symptoms. So I kind of, “Okay, that’s a bit weird.” My joints were getting worse. And then on the third month my joints, my ankles and my knees especially did just kind of d-, decrease to their normal ways. So I had to go, “Okay, that’s enough.” But it didn’t show in my bloods. So the hospital couldn’t do anything for me. So, as I said earlier, we had that kind of long decision, “Do I come out of the drug and look for something else? Or do I hold on for the next two months and hopefully they’ll put me in to the other extension?” But luckily, as I said earlier, they just kind of said, “No, we can move you in to the third extension.”


Sometimes it is not always clear whether symptoms are a result of the trial or just coincidence, but it is better to tell the doctors. Withdrawing from a trial because of side effects is entirely reasonable and no-one should feel they have to stay in for the sake of the trial or that they have failed if they pull out. (See also ‘Withdrawing from a trial’.)

Sometimes trials that do not involve drugs can also have side effects, for example minor surgery or tests that may leave you feeling uncomfortable. Several young people said they found blood tests and injections difficult. This is discussed in ‘What is involved in a trial: appointments and monitoring’. 

Sometimes there may be side effects from procedures involved in the trial as well as from the treatment itself. Robert is taking part in a Phase 1 gene therapy trial for the treatment of cystic fibrosis and because it is a Phase 1 trial, there is little known about the therapy. As well as receiving a dose of gene therapy he also had two bronchoscopies as part of the process to monitor his lungs.


Robert wasn’t prepared for some of the side effects he experienced, and is unsure if one was a...

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Sex: Male
Because the bronchoscopies were they’re a relatively routine procedure as it were. I didn’t really think oh yes there’s a risk I might lose my voice from this because I thought "Oh bronchoscopies people have those all the time don’t they". And so then it was a surprise when afterwards I just couldn’t talk and then, you know, it went on and on and then eventually my voice came back as I say my singing hasn’t really been the same since. And that has been a shame but well the best I can do is to try and get my, you know, try and practice more singing and get it back. But yes that wasn’t something I was prepared for. Whereas with the, with the rash on my legs and the meningitis scare that was something which it was about a month after I’d had the dose which is why it’s so unlikely that it was to do with that. But that was one I was perhaps more prepared for, you know, when I was on the way to the hospital the first thing I did was to ring the trial co-ordinator to let them know just in case it was to do with that. And so that was something perhaps I was more prepared for that there might be some unexplained effect but , you know the losing my voice I wasn’t really prepared for.
But did they sort of inform you, I mean in all of these did you; you must have had some information about them?
And was those sort of side effects explained in there that the side effects....?
Yes with, I mean the leg rash thing was such a rare thing I think that sort of was probably encompassed on the consent form under there might be some rare unexplained things that happen but it’s not very likely.
Like with the voice?
With the voice I don’t really remember, I think they said that it was likely you would be coughing a lot after you come round from the general anaesthetic and that you would get a very sore throat from it. But to lose a voice for, it was about a month was actually very unusual and so I did tell them as it was happening, oh well it’s not come back and they, and they did show concern and try to suggest things to help but yes it was quite extreme.
Yes, yes. I mean how did you feel at the time was it a concern?
Well sort of for the first week or two I just thought oh yes it will pass but then by, you know, sort of the third week when it’s not getting any better, you think “Oh is my voice ever going to come back, what’s happened”. And then it did steadily come back. And in fact one of these weeks I was on holiday with some friends in Belgium and it did make it a bit harder on that holiday when, you know, you have to really strain to make yourself heard. And so I guess it, yes it wasn’t so fun on the holiday not being able to talk so much with my friends but yes but otherwise it was just a thing that I had to just sit tight and wait for it to pass.
But you were still keen to continue taking part?
Yes yes I think I am. Because in fact that, the losing the voice was only after the first bronchoscopy, the second one wasn’t so bad so it might just be that that first time something happened that.


In all trials the treatment may cause side effects or problems that doctors cannot predict. This may happen more often when less is known about the treatment being tested. Eden is taking part in a randomised controlled trial of treatment for Hodgkin’s lymphoma that involves taking four different types of chemotherapy. She experienced many side effects from the treatment, but one of the drugs was causing unexpected side effects.

Alexander also experienced side effects. Some of these were explained in the information he received at the start of the trial, but some were unexpected. 


Soon after taking the medication Alexander felt poorly, and he sometimes found it hard to cope,...

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Age at interview: 18
Sex: Male
Age at diagnosis: 16
And the side effects you’ve mentioned. Can you tell me a bit more about those?
The side effects, I’ve found most of them. The main one in my opinion is probably the sleep deprivation. That’s the thing they didn’t mention at all. As if you’re a 4-year-old staying awake till 2 o’clock, it’s not actually that bad, because you probably used to going to bed about 8. So your body will only go, go so far. But when you get a bit older, your body learns to stay awake a lot longer. So staying awake till 2, you can do that easily. So now you can stay up two days without sleep. So you do physically and mentally struggle with day-to-day basis, just trying to work things out. That’s probably the biggest one to me, because not being switched on is not good. Probably the other one is, well, there’s quite a few, but the, my other kind of main one is the immune system. It gets knocked down. As my skin, as recently my s-, well, my skin’s been splitting since I’ve been having the drug and it won’t heal. So you’re on antibiotics quite a lot. They did mention this in the, this is what they did mention in the paperwork at the beginning, knowing about this. So I wasn’t as shocked as the sleep deprivation. So, but it does kind of knock your confidence down. Because if you’re kind of scaly and not very nice, trying to shake someone’s hand is not great.
Well, how does it come up then?
It kind of blisters and then it will eventually split and it will scar and, or it just won’t heal. So it can heal in a few days like a normal cut or it can heal in a few weeks with vast amounts of antibiotics on. Or if you have some, a friend or anyone, a colleague, a colleague who’s got a slight cold, if you go near them, you, I’ve noticed you’ll catch the cold a lot quicker and a lot easier. And that won’t just stay as a cold. It will kind of develop as a chest infection, a sinus infection etc. Another one is something I actually call the aggressive hunger. They haven’t mentioned it anywhere but, and no one else seems to have this, but the doctors keep saying this is because I’m getting better. But I used to be better; I used to play a lot of rugby, so I do know what it is not to eat, having like trainers and stuff. So I don’t think it’s that kind of hungry. You can eat as much as you physically want and you’ll be, still want more. It’s something you really have to learn to deal with. So that obviously puts a lot of weight on you. And because I can’t do as much exercise I can’t burn it off as well. And the last, what’s the last one? Which ones have I mentioned?
You’ve mentioned sleep dep…
Sleep, skin.
And the eating.
Eating and this last one.
Is there another one?
I thought we said four last time.
That is four. Sleep, eating…
Yes, it is, crikey. Yes, sorry about that.
And is that, did you, when did you notice those symptoms?
Oh, sorry, the last one is the flu-like symptoms after you have the medication. As soon as you take the medication, after a few hours you start feeling quite fluey and not great. But after, after call it about a week, after the first three days you do kind of decline into this kind of fluey-like state and you don’t want to mo

Last reviewed March 2017.
Last updated March 2017.
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