L-threo-DOPS treatment of orthostatic hypotension in Swedish patients with familial amyloidotic polyneuropathy (TTR-met30)

L-threo-DOPS is a synthetic precursor to norepinephrine (NE). In order to study its efficacy and dosage, we carried out an open pilot study in ten patients with orthostatic hypotension and a confirmed diagnosis of familial amyloidotic polyneuropathy (FAP). The initial dosage was 200 mg of L-threo-DOPS daily, with a weekly increment of 100 mg, until a maintenance dose was reached. Ten patients were treated for 12 weeks and five of them for 24 weeks. The blood pressure (BP) and pulse rate were monitored weekly. Before treatment, after four and 12 weeks, the patients underwent clinical and laboratory examinations. Nine patients completed the study. There was a rise in mean BP values in all measurements. After 12 weeks of treatment the rise in mean systolic BP values were statistically significant (p < 0,01) in all measurements in upright position. When treatment was withdrawn BP fell to almost the same levels as before and when treatment was restarted (five patients), there was again a rise in mean BP values. Before treatment, all patients suffered from mild to severe symptoms of orthostatic hypotension. After 12 weeks of treatment, eight out of nine patients were free of symptoms. Most frequent side effects were tachycardia and nausea, but no severe side effects were seen.