Phase 1: Focus groups
From the 98 People with Parkinson’s (PwP) and 17 carers (n=115 in total) who expressed an interest, 25 invited to participate in the focus groups. Of these, one declined, three did not respond and four did not attend their scheduled focus group.
The three focus groups comprised three to six participants (n=17 in total). Each focus group was homogenous in terms of its composition: two included PwPs (n=12) and one included carers (n=5).
The median (IQ) age range of participants was 65-74 (55-64, 65-74), 9 (53%) were women and 14 (82%) had no previous experience of switching from solid to liquid formulations of Parkinson’s medication. Participants were from England, Scotland, Wales and Northern Ireland.
Six themes were generated through the stage 1 inductive thematic analysis: (i) the process of change; (ii) impact on lifestyle; (iii) margin for error; (iv) reflections on ability to administer; (v) position in treatment pathway and (vi) curiosities.
The process of change
People with Parkinsons’ attachment to current medication was expressed as a barrier to switching to a liquid. This attachment was most attributed to their unease with change.
“The problem is we’re old and don’t like change.” (Person with Parkinson’s 2, focus group 2)
Carers acknowledged this barrier, expressing that a switch might result in PwPs being unfamiliar with their medicine in a d formulation, which may lead to a perceived loss of independence and control over their Parkinson’s management.
“There seems to be a reluctance once someone [with Parkinson’s] is established on a medication to change to a different type of formulation… it always raises suspicion as to it might be a different medication or it might have a different effect.” (Carer 4, focus group 3)
However, PwPs’ attachment to the status quo was not an insurmountable barrier. Reassurance from prescribers and access to information and resources were proposed strategies.
Impact on lifestyle
A key consideration for switching is that liquids are generally less portable and more challenging to store, making them less convenient than the tablets and capsules that PwPs are used to. Challenges associated with travelling with liquids, especially for people working or going on holiday, was a particular concern.
“If you’re still working and on liquid you’re having to take it in and out of work or else you have to get prescribed two bottles of the medication so there are you know just the physical nature of having a liquid I think presents problems on a practical level” (Person with Parkinson’s 3, focus group 1)
The aforementioned potential for loss of independence associated with liquids could also impact on lifestyle as liquids are practically more difficult to administer and therefore PwP may require support which is unavailable when travelling.
Carers were also concerned about the potential for loss of independence, fearing that the work associated with the increased complexity of liquid administration would need to be absorbed by them. However, if a liquid version of a Parkinson’s medication was more effective, they supported a switch.
“If the [liquid] delivered the actual drug in your body better then all of these things that we’ve talked about… syringes and filling it and getting the right amount and everything would all be put to one side” (Carer 2, focus group 3)
Some PwPs agreed that efficacy took priority, but others felt quality of life convenience were more important.
“If you were at the stage were you were choking taking tablets I mean obviously a liquid form would be much easier to take and if you were at that stage perhaps you wouldn’t be so concerned about you know travelling abroad… ” (Person with Parkinson’s 3, focus group 1)
This led to discussions amongst PwPs regarding their desire to appear ‘normal’ and to hide their Parkinson’s symptoms. Medicines administration, especially in social settings, was a potential risk to maintaining a sense of normality. They indicated that administering a liquid from a bottle would be less discreet than popping a tablet. Carers also felt that this would be important.
“I’m quite a sociable person I like to go out to dinner […] and go to concerts and things and I have sort of a hip flask with water in and I can just I just quietly take a tablet without many people noticing […] that’s very important to me actually to be a normal person as near normal as I can be” (Person with Parkinson’s 7, focus group 2)
Some PwPs felt that any advantage afforded by liquid Parkinson’s medicines are obsolete if they’re concomitantly prescribed non-liquid formulations for other conditions. Others suggested that there was merit in having a range of options for different situations, for example addressing a dislike of taking tablets and capsules in the morning when tablets and capsules are most difficult to swallow.
“Sometimes when I wake up in the morning I think oh I’ve got to swallow flipping pills first thing and that’s when I wouldn’t mind a liquid then […] I just hate it in the morning that’s my worst time” (Person with Parkinson’s 2, focus group 1)
Further, PwPs hypothesised that liquids may permit greater flexibility for incremental dose changes, noting that this liquid property would be advantageous in terms of an ease of personalising dosing regimens that is not possible with tablets or capsules.
“When I was first starting on one tablet I had to try and cut it in half 2mg was the smallest they made and I only wanted the one [1mg] and that was you know was not very practical but with a liquid you could do that easily” (Person with Parkinson’s 6, focus group 2)
Margin for error
Potential benefits of liquids were balanced with a perceived increased risk of things going wrong. Liquids are seen as more difficult to correctly administer compared to tablets or capsules. This heightened sense of risk was primarily associated with liquid doses not being pre-measured unlike for tablets and capsules. Overdoses and underdoses were therefore considered more likely.
Cognitive symptoms of Parkinson’s such as memory loss are also perceived to make scheduling and monitoring adherence to liquid doses more difficult, which carries risk. PwPs and carers noted that tablets and capsules are pre-measured, easily scheduled, compatible with support aids such as multi-compartment compliance aids, and distinctive in terms of colour and shape. Conversely, these were not recognised features of liquids, and therefore they may be less compatible for people with cognitive impairment.
Reflections on ability to administer
Challenges associated with measuring, taking and generally handling liquid formulations are further barriers to switching. Participants reflected on how the symptoms of Parkinson’s could make using liquids more difficult to take than tablets or capsules. Challenges with accurate dose measurement as well as the potential to spill or drop liquids were notable.
“if you knock the bottle over you’ve lost all that medication you need” (Person with Parkinson’s 2, focus group 2)
Position in treatment pathway
Whilst liquids were perceived on the whole to be more difficult to administer, they were perceived to be easier and less painful to swallow for people with oropharyngeal dysphagia (OD) relative to tablets or capsules.
“For people who are having problems with swallowing I have no doubt the liquid form is better” (Person with Parkinson’s 5, focus group 1)
The perception that liquids are more suited to or more acceptable in the ‘future’ prevailed. This was expressed by some participants as liquids being the domain of healthcare professionals and healthcare settings. Specifically, participants noted that liquids should only be administered in healthcare settings to offset their perceived risks.
PwPs and carers’ limited experience and knowledge of liquid medicines extends to their uncertainties regarding the properties of a liquid medicine. Notably, uncertaincies regarding how liquids are absorbed, digested and whether or not they could be safely diluted led to speculative discussions that liquids might wear off quicker, need to be taken more frequently and may potentially be less effective. PwPs and carers also expressed concerns about the taste and possible side effects of liquids.
“if it works quicker is there a downside you know later on after you’ve taken the liquid or does that mean you have to take the liquid if it’s faster acting more often smaller amounts more often” (Person with Parkinson’s 3, focus group 1)
However, the speculative properties of liquids were also enablers. A consistent example proposed was that liquids might have a faster onset of action, therefore better treating the ‘off’ periods of Parkinson’s.
“A liquid […] gets to the target quicker and therefore it’s less of an off time so that you take the meds and you can see the effect quicker” (Carer 2, focus group 3)
Phase 2: Questionnaire
A 23 item questionnaire was developed: 16 items were barriers; four were enablers; and three could be either a barrier or an enabler.
One hundred and forty-two questionnaire responses were received (n= 131 PwPs and 11 carers). Carer data are provided in Appendix 3 but excluded from the results and analysis as the number of responses did not reach sufficient sample size to achieve our maximum confidence interval threshold (see methods).
The median (IQ) respondent age range was 65-74 years (55-64, 65-74), of whom 72 (55%) were men and 128 (97.7%) administered their own medicine. Only six (4.6%) reported prior experience of switching.
Table 1 provides PwPs responses to questionnaire items organised into the relevant Theoretical Domains Framework (TDF) domains. Eleven items (five barriers and three enablers) spanning six TDF domains fulfilled the criterion for prioritisation. Of the five enablers, three had almost unanimous agreement: the flexibility offered by liquid medicines to allow for incremental dosage changes (72% ± 8), decline in Parkinson’s control (72% ± 8) and prescriber’s endorsement of a switch (70% ± 8Of the four barriers, only the perception that tablets/capsules would be easier to correctly dose than measuring liquids (72% ± 8) and prescriber’s opposition to a switch (70% ± 8) attracted similarly high agreement.
The five enablers were mapped to four TDF domains. Three barriers were mapped to the Environmental Context and Resources TDF domain and one to Social Influence. Figures 1 and 2 provide the barriers and enablers to switching from solid to liquid formulations of Parkinson’s medication, the corresponding TDF domains and the linked Behaviour Change Techniques.