Hypertension is a significant public health challenge with more than 50% of the UK population over 60 years of age suffering with this silent disease.1 Untreated hypertension is associated with increased cardiovascular risk, and controlling blood pressure (BP) prolongs life through a reduction in the incidence of myocardial infarction, heart failure, and cerebrovascular disease.1 The majority of patients (90%) suffer with primary hypertension where no identifiable cause is found, however there are some secondary causes related to renal, endocrine or vascular disease that should be considered (Table 1). BP results from the complex interactions of haemodynamic, neuronal, hormonal, and environmental factors that influence cardiac output (CO) and systemic vascular resistance (SVR). Pharmacological interventions target the body's mechanisms involved in BP control (Figure 1), namely the renin–angiotensin system, autonomic nervous system, vasodilatory mechanisms and intravascular volume. A significant number of patients requiring anaesthesia will have pre-existing hypertension, others may require a reduction in BP during the perioperative period. Therefore, an understanding of anti-hypertensive pharmacology is required.