Guanfacine for the Treatment of Spatial Neglect and Impaired Vigilance

The current study has a double-blind crossover design where patients will receive a single 2mg dose of oral guanfacine and a single dose of placebo. They will receive one of these on Day 2 of the study period and the other on Day 4.

They will be tested daily on Days 1 to 5 so that any test repetition or long-term drug effects can be gauged.

On days 2 and 4 they will be tested twice-once prior to drug/placebo administration and again 90 minutes after drug/placebo administration.

Tests will include standard pen-and-paper tasks for neglect as well as computerised tests of sustained attention and visual exploration. In our published pilot study (Malhotra et al, 2006) there was a suggestion that patients without damage to frontal cortex were more likely to respond to guanfacine. In the current study we intend to test 10 patients with and 10 patients without frontal damage in order to test this further.

Inclusion criteria

• Age 18 or more
• Greater than 2 weeks following stroke
• Ability to give consent
• Evidence of robust Visual Neglect when tested twice with cancellation tasks.

Exclusion criteria

• Less than 2 weeks following stroke
• Concomitant illness that may affect interpretation of any findings
• Labile blood pressure following stroke
• Systolic BP less than 100 mmHg and / or diastolic less than 70 mmHg
• New antihypertensive medication started within last 3 weeks
• Patients with hepatic or renal dysfunction
• Patients receiving other medications known to potentiate guanfacine's antihypertensive and hypotensive effects or cause torsade de pointes, specifically antipsychotics (including sultopride, chlorpromazine, thioridazine, amisulpiride, sulpiride, haloperidol), and moxifloxacin, baclofen, verapamil, quinidine, hydroquinidine, dispyramide, amiodarone, dofetilide, ibutilide, sotalol, pimozide, bepridil, cisapride, diphemanil, erythromycin IV, halofantrine, pentamidine, sparfloxacin, vincamine, alfuzosin, prazosin, terazosin, tamsulosin, amifostine
• Patients with diagnosis of brain tumour
• Patients with weight less than 55kg
• Patients who are pregnant
• Mothers who are breast feeding
• Patients with severe coronary insufficiency or myocardial infarction in previous 6 months
• Cognitive impairment, dysphasia or dementia that prevents patient from giving informed consent
• Severe mental impairment or physical handicap following stroke that prevents patients from giving consent or performing basic (standard clinical) tests for neglect