The effects of caffeine in adults with neurogenic orthostatic hypotension: a systematic review

Purpose To systematically review the evidence base for the effectiveness and safety of caffeine for the treatment of neurogenic orthostatic hypotension in adults. Methods Eight electronic databases were searched in January 2021. Original research studies or case reports involving adults with neurogenic orthostatic hypotension were included if caffeine was an intervention and outcomes included symptoms, blood pressure or adverse effects. Relevant studies were screened and underwent qualitative analysis. Insufficient reporting precluded meta-analysis. Results Five studies were identified: four crossover studies and one case report summation. Study size ranged from 5 to 16 participants. Participants had neurogenic orthostatic hypotension, with a mean standing systolic blood pressure of 86 mmHg. Two studies evaluated caffeine alone. Three studies administered caffeine in combination with ergotamine. Caffeine dose ranged from 100 to 300 mg. Nature and timing of outcomes measured varied between studies, with measurements being recorded from 30 to 480 min after intervention. Caffeine/ergotamine improved symptoms in one study and reduced orthostatic blood pressure drop in two studies. Caffeine/ergotamine increased seated blood pressure in three studies, whilst the results for caffeine alone were inconsistent. No serious adverse events were reported. All studies demonstrated high risk of bias. Conclusion Caffeine should only be considered as a treatment for adults with neurogenic orthostatic hypotension when evidence-based treatments have been exhausted. Systematic review registration PROSPERO ID: CRD42020124589. Date of registration: 30/10/2020