Inclusion Criteria- Adult(> 18 yrs).
- Clinical stroke syndrome with limb weakness lasting at least 1 hour i.e. not likely to be a transient ischaemic attack).
- Limb weakness (SNSS Arm <6 and/or Leg <6).
- Onset < 48 hours.
- Conscious (Glasgow Coma Scale > 8).
- Independent prior to stroke (pre-morbid Rankin scale < 2).
- Meaningful consent, or assent from a relative or carer
Exclusion Criteria- Definite need for nitrate therapy
- Contraindication to nitrate therapy
- Definite need for prior antihypertensive or anti-anginal medication
- Definite need for antihypertensive therapy during acute stroke
- Systolic blood pressure <140 mmHg or >220 mmHg.
- Patients expected to require surgical intervention
- Known intracerebral pathology other than stroke
- Other serious condition which is likely to prevent outcome assessment at 3 months
- Previous enrollment in ENOS or current involvement in another trial of an experimental drug intervention.
- Not available for follow-up -Females of childbearing potential, pregnancy or breastfeeding. -