Certain drugs such as troleandomycin (TAO), erythromycin ( Ery-Tab , EryPed 200), and clarithromycin ( Biaxin ) and ketoconazole ( Nizoral ) can reduce the ability of the liver to metabolize (breakdown) corticosteroids and this may lead to an increase in the levels and side effects of corticosteroids in the body. On the other hand, phenobarbital, ephedrine , phenytoin ( Dilantin ), and rifampin ( Rifadin , Rimactane ) may reduce the blood levels of corticosteroids by increasing the breakdown of corticosteroids by the liver. This may necessitate an increase of corticosteroid dose when they are used in combination with these drugs.
Narrative: Post-herpetic neuralgia (PHN) is a syndrome of continued and chronic pain after the development of shingles, which is a reactivation of the varicella zoster (chickenpox) virus. The likelihood of developing shingles increases with age, with estimates of 10-20% incidence throughout one’s lifetime. The risk of developing post-herpetic neuralgia also increases with age, and is rare in patients under 30. PHN is exquisitely painful and debilitating, and unfortunately few effective treatments exist. It is theorized that treatment with steroids before the PHN develops may reduce the risk of PHN developing.
This Cochrane review concludes that data are clearly lacking. While 787 subjects in 5 trials were deemed sufficient to evaluate this question, only one study (with 34 subjects) compared steroids to placebo. Other studies compared steroids to placebo or no treatment (we assume because there was no possible role for a placebo effect); still other studies compared an anti-viral plus steroids to an anti-viral plus placebo (and evaluated pain scales but not the binary outcome of yes/no PHN). The review, however, does suggest that there may be benefits in terms of pain scales at 6 months after zoster diagnosis , or in certain age subgroups for zoster.
Harms were rare , and were not statistically more common in placebo and steroid arms.
Of note, the classic teaching of “steroids within 48-72 hours of rash development" was not conclusive in any of the high-quality studies chosen for inclusion by the Cochrane Group.
In summary, further research with larger populations is needed to answer this question.
Because of these side effects, doctors frequently choose safer medications, such as the 5-ASA drugs and antibiotics, as initial therapy. But there are a number of ways to reduce the risk of developing side effects. These include rapid but careful tapering off of steroids; alternate-day dosing; rectally applied corticosteroids; and rapidly metabolized corticosteroids such as budesonide (described above). To help prevent osteoporosis, many doctors routinely prescribe calcium supplements as well as multivitamins that contain vitamin D. Another option is the use of bisphosphonates, such as risedronate (Actonel®) and alendronate (Fosamax®). These compounds, which have been shown to help avert bone loss, are effective in treating and preventing steroid-induced osteoporosis.