Personalised Electronic Record Supported Optimisation of Amlodipine for Patients With Hypertension

Hypertension is the leading preventable cause of premature death worldwide. Globally, 1.39bn people are estimated to have hypertension, and it caused ≈10.7 million deaths in 2015. It is projected to affect more than 1.5 billion people around the world by 2025. In the UK \~30% of adults have hypertension3; 9.5m have a diagnosis, and a further 5m people in England alone may have hypertension yet be unaware. The annual incidence of new cases is 5-8%5. Physician inertia (inadequate up-titration of treatment, especially from monotherapy) and poor patient adherence to treatment (especially when based on multiple pills) are now recognised as major factors contributing to poor BP control. Amlodipine is a calcium-channel blocking drug which reduces blood pressure by relaxing blood vessels (especially veins) but this same effect makes it prone to causing fluid accumulation (oedema) in the lower limbs. Approved by the FDA in the United States in 1987, there is a large amount of evidence on its effectiveness and safety in reducing blood pressure and in treating stable angina. There appears to be a close relationship between wanted and unwanted effects. Finding the best dose of amlodipine for a patient could be useful in optimizing their blood pressure treatment. At present the tablet doses available are only 5mg and 10mg in the UK. In the present study the investigators will investigate the relationship between patient beliefs about medicines using the Beliefs about Medicines Questionnaire (BMQ) developed by Horne, Weinman and Hankins (1999)13 and their adherence using the Morisky Medication Adherence Scale - 8 14. The investigators hypothesize that patients' tolerability of side effects (as measured by VAS) will be related to their beliefs about the necessity of medication (necessity concerns), their concerns about side effects and their adherence to medication. This study will only look at doses within the current maximum licensed 10mg dose. The investigators will ask patients who have had previous problems with unwanted effects of amlodipine at conventional doses to have careful monitoring of blood pressure over 24 hours using an ambulatory blood pressure monitor. If blood pressure control on their maximum tolerated conventional dose of amlodipine (0 or 5mg) is inadequate (systolic daytime average =\>135 mmHg and/or diastolic daytime average =\>85 mmHg), then patients will be eligible for the study. Those taking 5mg amlodipine tablets daily will be given amlodipine liquid to take at the same 5mg dose to convert to liquid formulation dosing. Patients will be issued with standard home blood pressure monitors and will be asked to measure their blood pressure in the morning (three readings) before taking their tablet (trough treatment) and again in the evening (three readings). Patients will attend every two weeks, following screening with clinical history taking, haematology, biochemistry, HbA1c, routine physical examination and resting ECG. Every two weeks patients will have clinic blood pressure measurements and review of home BP monitoring