Intestinal obstruction associated with oral midodrine

Midodrine use in critically ill patients: a narrative review

Midodrine is a peripherally acting, oral α-agonist that is increasingly used in intensive care units despite conflicting evidence for its effectiveness. It has pharmacological effects on blood vessels as well as pupillary, cardiac, renal, gastrointestinal, genitourinary, lymphatic and skin tissue. It has approval for use as a treatment for orthostatic hypotension, but a surge in interest over the past decade has prompted its use for a growing number of off-label indications. In critically ill patients, midodrine has been used as either an adjunctive oral therapy to wean vasoplegic patients off low dose intravenous vasopressor infusions, or as an oral vasopressor agent to prevent or minimise the need for intravenous infusion. Clinical trials have mostly focused on midodrine as an intravenous vasopressor weaning agent. Early retrospective studies supported its use for this indication, but more recent randomised controlled trials have largely refuted this practice. Key questions remain on its role in managing critically ill patients before intensive care admission, during intensive care stay, and following discharge. This narrative review presents a comprehensive overview of midodrine use for the critical care physician and highlights why lingering questions around ideal patient selection, dosing, timing of initiation, and efficacy of midodrine for critically ill patients remain unanswered.

Management of hypertension in the setting of autonomic dysfunction

Supine hypertension is a common finding in patients with autonomic failure; it is associated with end-organ damage and produces nighttime pressure diuresis with worsening of orthostatic hypotension. During the daytime, it is best treated by avoiding the supine posture. At night, simple measures such as raising the head of the bed by 6 to 9 inches can be effective, but most patients require pharmacologic treatment. Transdermal nitroglycerin (0.1 to 0.2 mg/h) or nifedipine (30 mg, orally) has proved to be effective. Hydralazine and minoxidil are usually less effective but may be useful in a given patient. One key therapeutic concept is the hypersensitivity of these patients to depressor agents, requiring a careful titration of the doses on an individual basis. For those patients with proven residual sympathetic tone, as in multiple system atrophy, central sympatholytics such as clonidine may provide an alternative.

Adverse drug reactions related to drugs used in orthostatic hypotension: a prospective and systematic pharmacovigilance study in France

OBJECTIVE

The aim of the present study was to investigate and characterise adverse drug reactions (ADRs) to drugs used in France for orthostatic hypotension (OH).

METHODS

In this prospective and systematic study, 121 consecutive out-patients suffering from primary (Parkinson's disease, pure autonomic failure, multiple system atrophy, Lewy bodies disease) or secondary (diabetic and non-diabetic peripheral neuropathies) autonomic failure with symptomatic OH requiring pharmacological treatment with at least one drug marketed in France for OH were included together with six patients with refractory neurocardiogenic syncope.

RESULTS

Of the patients, 85 received a monotherapy-mainly with midodrine (49.4%)-and 42 received various combinations, the association of midodrine and fludrocortisone being the most frequent (66.6%). Of all the 127 patients, 88 suffered from a total of 141 ADRs (1.60 per patient) with no statistical difference in ADR frequency between monotherapy and drug combinations (P>0.05). Among ADRs, 24 (17.0%) were considered as "serious" and 16 (11.3%) were considered as "unexpected", most of them observed with heptaminol.

CONCLUSIONS

This study shows a high frequency of ADRs (especially serious and unexpected ADRs) with antihypotensive drugs. It strongly suggests the need for a better evaluation of the safety profile of antihypotensive drugs and improvement in summary of product characteristics.