Which Medications Can Cause Edema?

Edema in the feet and legs is a common complaint in our practices. It can cause pain, weakness, heaviness, discomfort, limited movement, and a negative body image. Medications can contribute to edema, either alone or in combination with other health issues.

Edema is also associated with advanced age, female sex, obesity, diabetes, hypertension, pain, lack of physical activity, and mobility limitations. These factors often necessitate medication prescriptions, which can aggravate the problem. Therefore, it is important to know how to treat or prevent medication-induced edema.

There are four main causes of edema, and all can facilitate medication-induced edema.

• Increased capillary pressure. Conditions such as heart failure, renal dysfunction, venous insufficiency, deep vein thrombosis, and cirrhosis can increase capillary pressure, leading to edema.
• Decreased oncotic pressure. Hypoalbuminemia, a primary cause of reduced colloid oncotic pressure, can result from nephrotic syndrome, diabetic nephropathy, lupus nephropathy, amyloidosis, nephropathies, cirrhosis, chronic liver disease, and malabsorption or malnutrition.
• Increased capillary permeability. Vascular injury, often associated with diabetes, can increase capillary permeability and contribute to edema.
• Impaired lymphatic drainage. Lymphatic obstruction is common in patients with lymphedema, tumors, inflammation, fibrosis, certain infections, surgery, and congenital anomalies. Conditions such as thyroid disorders can also cause an increase in interstitial albumin and other proteins without a corresponding increase in lymphatic flow, leading to lymphedema.

Medications That Can Cause Edema

• Calcium channel blockers (CCBs). Drugs such as nifedipine and amlodipine can increase hydrostatic pressure by causing selective vasodilation of precapillary vessels, leading to increased intracapillary pressures. Newer lipophilic CCBs (eg, levamlodipine) exhibit lower rates of edema. Reducing the dose is often effective. Diuretics are not very effective for vasodilation-induced edema. Combining CCBs with angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs), which induce postcapillary dilation and normalize intracapillary pressure, may reduce fluid leakage into the interstitial space. This combination may be more beneficial than high-dose CCB monotherapy.
• Thiazolidinedione (eg, pioglitazone). These increase vascular permeability and hydrostatic pressure. They work by stimulating the peroxisome proliferator–activated gamma receptor, increasing vascular endothelial permeability, vascular endothelial growth factor secretion, and renal retention of sodium and fluids. Because of other adverse effects, their use is now limited.
• Agents for neuropathic pain (gabapentin and pregabalin). These drugs can induce selective vasodilation of arterioles through a mechanism similar to that of CCBs, causing increased intracapillary pressures. Edema usually begins within the first month of treatment or dose increase and often regresses after dose reduction or drug discontinuation.
• Antiparkinsonian dopamine agonists. These increase hydrostatic pressure by reducing sympathetic tone and dilating arterioles through alpha-2 adrenergic receptor activity.
• New antipsychotics. Drugs like clozapine, iloperidone, lurasidone, olanzapine, quetiapine, risperidone, and ziprasidone can increase hydrostatic pressure through antagonistic effects on alpha-1 adrenergic receptors, causing vasodilation.
• Nitrates. These drugs increase hydrostatic pressure by causing preferential venous dilation, leading to increased venous pooling.
• Nonsteroidal anti-inflammatory drugs (NSAIDs). These drugs can increase hydrostatic pressure by inhibiting vasodilation of afferent renal arterioles, decreasing the glomerular filtration rate, and stimulating the renin-angiotensin-aldosterone system, which leads to sodium and water retention. These adverse effects warrant cautious use of these agents.
• ACE inhibitors. Drugs such as enalapril and ramipril can increase vascular permeability. They reduce the metabolism and accumulation of bradykinin, which increases vascular permeability and fluid leakage. These effects are rare and are usually related to allergic responses.
• Insulin. Insulin decreases capillary oncotic pressure and increases vascular permeability. Rapid correction of hyperglycemia can cause a loss of oncotic pressure, while chronic hyperglycemia can damage vascular membranes, increasing permeability. These effects are generally benign and can be managed with careful dose titration, sodium restriction, or diuretics.
• Steroids. Steroids with mineralocorticoid activity can increase renal sodium and water retention, leading to increased blood volume. Fludrocortisone has the highest mineralocorticoid activity, while dexamethasone and methylprednisolone have negligible activity.