Multiple drug-intolerant hypertension: a case series utilising a novel-treatment algorithm.

Poor adherence to antihypertensive medication is a major cause of suboptimal blood pressure (BP) control1 and frequently arises from intolerance to antihypertensive medications due to adverse drug reactions (ADRs). A meta-analysis of antihypertensive drug trials using monotherapies demonstrated that ADRs occur in up to 39% of patients, resulting in a frequency of discontinuations of medication from 6.8–17%.2 These ADRs can be due to hypersensitivity reactions or dose-dependent, pharmacologically predictable adverse effects. In addition, patients also report bizarre, unpredictable reactions, without a clear pharmacological basis, which are sufficiently debilitating to warrant discontinuation of treatment.We classify hypertensive patients who have documented intolerances to three or more unrelated classes of antihypertensive medication as having multiple drug-intolerant hypertension (MDI-HTN).3 Such patients are unable to take antihypertensive drugs recommended by standard guideline-based algorithms4 and are difficult to manage, as treatment options are limited. This results in uncontrolled hypertension with end-organ damage and poor quality of life.5We developed a novel pharmacological stepwise treatment protocol (Figure 1) to improve BP control in patients with MDI-HTN.3 At step 1 patients are tried on fractional doses of antihypertensive medication by quartering or halving tablets. If not tolerated or if BP is uncontrolled, step 2 comprises antihypertensive medication in liquid formulations, often at one-tenth of standard doses. If not tolerated or if BP is not at target, step 3 utilises transdermal patches of glyceryl trinitrate (GTN) or clonidine. Step 4 is to try drugs unlicensed for hypertension but known to lower BP such as 5-phosphodiesterase inhibitors (5-PDEI)6 or long-acting mononitrates.7Figure 1. Multiple drug-intolerant hypertension (MDI-HTN) treatment algorithm. We describe a case series using this novel stratified approach. These cases were secondary/tertiary referrals to the Barts BP …