What are the differences between prednisone vs. dexamethasone?

What are prednisone and dexamethasone?

Prednisone and dexamethasone are synthetic (man-made) corticosteroids (steroids) used for suppressing the immune system and inflammation. These drugs have effects similar to other corticosteroids such as triamcinolone (Kenacort), methylprednisolone (Medrol), and prednisolone (Prelone).

These synthetic corticosteroids mimic the action of cortisol (hydrocortisone), the naturally-occurring corticosteroid produced in the body by the adrenal glands. There are numerous preparations of corticosteroids including tablets, capsules, liquids, topical creams and gels, inhalers, eye drops, as well as injectable and intravenous solutions.

What are the side effects of prednisone and dexamethasone?

Prednisone

Side effects of prednisone and other corticosteroids range from mild annoyances to serious, irreversible organ damage, and they occur more frequently with higher doses and more prolonged treatment.

Common side effects include:

  • Retention of sodium (salt) and fluid
  • Weight gain
  • High blood pressure
  • Loss of potassium
  • Headache
  • Muscle weakness
  • Nausea
  • Vomiting
  • Acne
  • Thinning skin
  • Restlessness
  • Problems sleeping

Serious side effects include:

This drug also causes psychiatric disturbances, which include:

Other possible serious side effects of this drug include:

Prednisone and diabetes: Prednisone is associated with new onset or manifestations of latent diabetes, and worsening of diabetes. Diabetics may require higher doses of diabetes medications while taking prednisone,

Allergic reaction: Some people may develop a severe allergic reaction (anaphylaxis) to prednisone that includes swelling of the airways (angioedema) that may result in shortness of breath or airway blockage.

Immune suppression: Prednisone suppresses the immune system and, therefore, increases the frequency or severity of infections and decreases the effectiveness of vaccines and antibiotics.

Osteoporosis: Prednisone may cause osteoporosis that results in fractures of bones. Patients taking long-term prednisone often receive supplements of calcium and vitamin D to counteract the effects on bones. Calcium and vitamin D probably are not enough, however, and treatment with bisphosphonates such as alendronate (Fosamax) and risedronate (Actonel) may be necessary. Calcitonin (Miacalcin) also is effective. The development of osteoporosis and the need for treatment can be monitored using bone density scans.

Adrenal insufficiency and weaning off prednisone: Prolonged use of prednisone and other corticosteroids causes the adrenal glands to atrophy (shrink) and stop producing the body's natural corticosteroid, cortisol.

Necrosis of hips and joints: A serious complication of long-term use of corticosteroids is aseptic necrosis of the hip joints. Aseptic necrosis is a condition in which there is death and degeneration of the hip bone. It is a painful condition that ultimately can lead to the need for surgical replacement of the hip. Aseptic necrosis also has been reported in the knee joints. The estimated incidence of aseptic necrosis among long-term users of corticosteroids is 3%-4%. Patients taking corticosteroids who develop pain in the hips or knees should report the pain to their doctors promptly.

Dexamethasone

Side effects of dexamethasone depend on the dose, the duration and the frequency of administration. Short courses of dexamethasone usually are well tolerated with few and mild side effects. Long term, high dose dexamethasone usually will produce predictable and potentially serious side effects. Whenever possible, the lowest effective dose of dexamethasone should be used for the shortest possible length of time to minimize side effects. Alternate day dosing also can help reduce side effects.
Side effects of dexamethasone and other corticosteroids range from mild annoyances to serious irreversible damage. Side effects include:

  • fluid retention,
  • weight gain,
  • high blood pressure,
  • loss of potassium,
  • increase in serum glucose levels (especially in diabetics),
  • headache,
  • muscle weakness,
  • puffiness of and hair growth on the face,
  • thinning and easy bruising of skin,
  • glaucoma,
  • cataracts,
  • peptic ulceration,
  • worsening of diabetes,

Other side effects include:

  • irregular menses,
  • growth retardation in children,
  • convulsions, and
  • psychic disturbances.

Psychic disturbances include:

Prolonged use of dexamethasone can depress the ability of body's adrenal glands to produce corticosteroids. Abruptly stopping dexamethasone in these individuals can cause symptoms of corticosteroid insufficiency, with accompanying nausea, vomiting, and even shock. Therefore, withdrawal of dexamethasone usually is accomplished by gradually reducing the dose. Gradually tapering dexamethasone not only minimizes the symptoms of corticosteroid insufficiency, but also reduces the risk of an abrupt flare of the disease under treatment.

Dexamethasone and other corticosteroids can mask signs of infection and impair the body's natural immune response that is important in fighting infection. Patients on corticosteroids are more susceptible to infections and can develop more serious infections than individuals not receiving corticosteroids. For example, chickenpox and measles viruses can produce serious and even fatal illnesses in patients on high doses of dexamethasone. Live virus vaccines, such as smallpox vaccine, should be avoided in patients taking high doses of dexamethasone, since even vaccine viruses may cause disease in these patients. Some infectious diseases, such as tuberculosis (TB) and malaria, can remain dormant in a patient for years. Dexamethasone and other corticosteroids can reactivate dormant infections. Patients with dormant tuberculosis may require treatment of the TB while undergoing corticosteroid treatment.

By interfering with the patient's immune response, dexamethasone can impede the effectiveness of vaccinations. Dexamethasone can also interfere with the tuberculin (TB) skin test and cause falsely negative results in patients with dormant tuberculosis infection.

Dexamethasone impairs calcium absorption and new bone formation. Patients on prolonged treatment with dexamethasone and other corticosteroids can develop osteoporosis and an increased risk of bone fractures. Supplemental calcium and vitamin D are encouraged to slow this process of bone thinning. It has been demonstrated in some groups of patients treated with steroids that the loss of bone may be prevented by treatment with biphosphonate drugs, for example, alendronate (Fosamax).

In rare individuals, destruction of large joints can occur while undergoing treatment with dexamethasone or other corticosteroids. These patients experience severe pain in the involved joints, and can require joint replacements. The reason behind such destruction is not clear.

What is the dosage of prednisone vs. dexamethasone?

Prednisone

The initial dosage of prednisone varies depending on the condition being treated and the age of the patient.

  • It's recommended that you take this medication with food.
  • The starting dose may be from 5 mg to 60 mg per day, and often is adjusted based on the response of the disease or condition being treated.
  • Corticosteroids typically do not produce immediate effects and must be used for several days before maximal effects are seen. It may take much longer before conditions respond to treatment.
  • When prednisone is discontinued after a period of prolonged therapy, the dose of prednisone must be tapered (lowered gradually) to allow the adrenal glands time to recover.

Dexamethasone

  • Dosage requirements of corticosteroids vary greatly among individuals and the diseases being treated. In general, the lowest possible effective dose is used.
  • The initial oral dose is 0.75 mg to 9 mg daily depending on the disease. The initial dose should be adjusted based on response.
  • Corticosteroids given in multiple doses (2 to 4 times daily) throughout the day are more effective but also are more toxic as compared with the same total daily dose given once daily, or every other day.

What drugs interact with prednisone and dexamethasone?

Prednisone

Prednisone interacts with many drugs, examples include:

  • Prednisone may interact with estrogens and phenytoin (Dilantin). Estrogens may reduce the action of enzymes in the liver that break down (eliminate) the active form of prednisone, prednisolone. As a result, the levels of prednisolone in the body may increase and lead to more frequent side effects.
  • Phenytoin increases the activity of enzymes in the liver that break down (eliminate) prednisone and thereby may reduce the effectiveness of prednisone. Thus, if phenytoin is being taken, an increased dose of prednisone may be required.
  • The risk of hypokalemia (high potassium levels in the blood) increases when corticosteroids are combined with drugs that reduce potassium levels (for example, amphotericin B, diuretics), leading to serious side effects such as heart enlargement, heart arrhythmias and congestive heart failure.
  • Corticosteroids may increase or decrease the response warfarin (Coumadin, Jantoven). Therefore, warfarin therapy should be monitored closely.
  • The response to diabetes drugs may be reduced because prednisone increases blood glucose.
  • Prednisone may increase the risk of tendon rupture in patients treated with fluoroquinolone type antibiotics. Examples of fluoroquinolones include ciprofloxacin (Cipro) and levofloxacin (Levaquin).
  • The elderly are especially at risk and tendon rupture may occur during or after treatment with fluoroquinolones.
  • Combining aspirin, ibuprofen (Motrin) or other nonsteroidal anti-inflammatory agents (NSAIDS) with corticosteroids increases the risk of stomach related side effects like ulcers.
  • Barbiturates, carbamazepine, rifampin and other drugs that increase the activity of liver enzymes that breakdown prednisone may reduce blood levels of prednisone. Conversely, ketoconazole, itraconazole (Sporanox), ritonavir (Norvir), indinavir (Crixivan), macrolide antibiotics such as erythromycin, and other drugs that reduce the activity of liver enzymes that breakdown prednisone may increase blood levels of prednisone.

Dexamethasone

Corticosteroids may increase or decrease the effect of blood thinners, for example, warfarin (Coumadin). Blood clotting should be monitored and the dose of blood thinner adjusted in order to achieve the desired level of blood thinning when patients receiving blood thinners are begun on corticosteroids, including dexamethasone.

Phenobarbital, ephedrine, phenytoin (Dilantin), and rifampin (Rifadin, Rimactane) may increase the breakdown of corticosteroids by the liver, resulting in lower blood levels and reduced effects. Therefore, the dose of corticosteroid may need to be increased if treatment with any of these agents is begun.

Mifepristone may reduce the action of corticosteroids via unknown mechanisms. Dexamethasone may decrease blood levels of mifepristone. Mifepristone should not be combined with steroids.

Are prednisone and dexamethasone safe to use while pregnant or breastfeeding?

Prednisone

  • Corticosteroids cross the placenta into the fetus. Compared to other corticosteroids, however, prednisone is less likely to cross the placenta. Chronic use of corticosteroids during the first trimester of pregnancy may cause cleft palate.
  • Corticosteroids are secreted in breast milk and can cause side effects in the nursing infant. Prednisone is less likely than other corticosteroids to be secreted in breast milk, but it may still pose a risk to the infant.

Dexamethasone

  • Use of dexamethasone in pregnant women has not been adequately studied. When corticosteroids are given systemically (orally, intramuscularly, or intravenously) to pregnant animals fetal abnormalities occurred.
  • Dexamethasone has not been adequately evaluated in nursing mothers. Corticosteroids appear in breast milk and may cause side effects in infants.

Summary

Prednisone and dexamethasone are synthetic corticosteroids used for suppressing the immune system and inflammation. Both drugs are used to treat many conditions including:

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Medically Reviewed on 10/31/2017
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