How do steroids increase blood pressure?

Mechanisms of Steroid-Induced Blood Pressure Elevation

Steroids raise blood pressure through multiple mechanisms including sodium and water retention, increased cardiac output, enhanced vascular sensitivity to catecholamines, and direct effects on vascular tone, with mineralocorticoid effects being most prominent but not essential for hypertension development. 1, 2

Primary Mechanisms

Corticosteroids increase blood pressure through several distinct pathways:

1. Mineralocorticoid Effects

• Sodium and water retention: Steroids, particularly those with mineralocorticoid activity, cause elevation of blood pressure through salt and water retention 2
• Increased plasma volume: This leads to expanded extracellular fluid volume and increased cardiac output 3
• Potassium excretion: Corticosteroids increase potassium excretion, which can contribute to hypertension 2

2. Non-Mineralocorticoid Mechanisms

• Increased vascular sensitivity to catecholamines: Cortisol increases pressor responsiveness to both endogenous and exogenous catecholamines without necessarily increasing sympathetic nervous activity 3
• Direct vascular effects: Synthetic glucocorticoids (prednisolone, methylprednisolone, triamcinolone, dexamethasone) can raise blood pressure without plasma volume expansion or sodium retention 4
• Hypertensinogenic mechanism: Evidence suggests steroids may raise pressure through a mechanism distinct from classical mineralocorticoid or glucocorticoid effects 3, 5

Clinical Manifestations

The hypertensive effect of steroids has several important clinical characteristics:

• Dose-dependent effect: Higher doses cause more significant blood pressure elevation 1, 2
• Rapid onset: Blood pressure elevation can develop within 4-6 hours of steroid administration 5
• Abnormal diurnal pattern: Chronic steroid use can cause flattening of the normal diurnal blood pressure curve 6
• Paradoxical hypertension during withdrawal: Some patients, particularly children with asthma, may develop hypertension during steroid reduction rather than during maximum dosing 7

Risk Factors for Steroid-Induced Hypertension

Certain factors increase the risk of developing hypertension with steroid therapy:

• Elderly patients 2
• Higher baseline blood pressure 1
• Concurrent use of other medications that raise blood pressure 1
• Kidney disease 1
• Higher doses and longer duration of therapy 2

Monitoring and Management

For patients on steroid therapy:

• Regular blood pressure monitoring is essential, especially in high-risk groups
• Consider sodium restriction for patients on steroids with mineralocorticoid effects 2
• Potassium supplementation may be necessary 2
• When possible, use the lowest effective dose for the shortest duration
• For patients requiring long-term therapy, consider synthetic steroids with less mineralocorticoid activity, though this will not completely prevent hypertension 4

Clinical Pitfalls

1. Assuming only mineralocorticoid steroids cause hypertension: Even synthetic glucocorticoids with minimal mineralocorticoid activity can cause significant blood pressure elevation 4

2. Missing withdrawal hypertension: Blood pressure may paradoxically rise during steroid reduction rather than at peak dosing 7

3. Overlooking drug interactions: NSAIDs and other medications can exacerbate steroid-induced hypertension by antagonizing the effects of antihypertensive medications 1

4. Failing to monitor pediatric patients: Children on steroids require careful blood pressure monitoring as they are also susceptible to steroid-induced hypertension 1, 2

Understanding these mechanisms is crucial for appropriate monitoring and management of patients receiving steroid therapy, particularly those at higher risk for cardiovascular complications.