Adverse Effects of Interferons

Adverse effects of interferon, pegylated interferon, and ribavirin therapy... 

Bayas A, Reickmann R Managing the adverse effects of interferon-(3 therapy in multiple sclerosis. Drug Saf 2000 22 149-159. 

The adverse effects of interferon alfa-2b include fever and a fiulike syndrome of muscle ache, fatigue, headache, anorexia, and nausea. Other less common side effects include leukopenia, diarrhea, dizziness, and skin rash. 

A middle-aged woman developed subacute thyroiditis by the sixth month of treatment with interferon alfa (508). She also had the classic symptoms of hyperthyroidism, although it is clear that these could easily have been mistaken for adverse effects of interferon alfa itself, for example weakness, weight loss, and palpitation. 

Severe hypertriglyceridemia, a well-known adverse effect of interferon beta, has been reported and fully investigated in a 39-year-old man receiving interferon beta for chronic hepatitis C (563). 

Neuropsychiatric complications of interferon alfa were recognized in the early 1980s and represent one of the most disturbing adverse effects of interferon alfa (SED-13, 1091 SEDA-20, 327 SEDA-22, 400). Reviews have provided comprehensive analysis of the large amount of experimental and clinical data that have accumulated since 1979 (321,322). 

Raison CL, Demetrashvili M, Capuron L, Miller AH. Neuropsychiatric adverse effects of interferon-alpha recognition and management. CNS Drugs 2005 19 105-23. 

Valentine AD. Managing the neuropsychiatric adverse effects of interferon treatment. BioDrugs 1999 11 229-37. 

The adverse effects of interferon alfa have mostly been reported after systemic administration, as intranasal use was not associated with more frequent adverse effects than placebo (13). Almost aU patients treated with interferon alfa have experienced adverse effects, most of which are mild to moderate in intensity and easily manageable without withdrawal of treatment (14). The incidence and profile of adverse effects reported with the available tjfpes... 

The respiratory adverse effects of interferon alfa include interstitial pneumonitis (38), which is rare. Since the first description of interstitial pneumonitis associated with interferon alfa in Japanese patients who also used the popular Sho-saiko-t herbal formulation, similar cases have been described in Western patients, suggesting that interferon alfa can be the sole cause in some patients (SED-13,1091) (SEDA-20, 326) (SEDA-21, 370) (39,40). 

A flu-like illness is the most common adverse effect of interferon beta. In an open, randomized study of the effects of paracetamol 1 g or ibuprofen 400 mg before and 6 hours after interferon beta injection on interferon beta-induced flu-like symptoms in 104 patients, the two drugs were equally effective (11). 

Cardiovascular adverse effects of interferon beta include isolated reports of severe Raynaud s phenomenon (SEDA-22, 374) and acute myocarditis (SEDA-21, 374). 

Although headache was not specifically identified as an adverse effect of interferon beta in pivotal trials, the frequency, duration, and intensity of headache increased during the first 6 months of treatment in 65 patients (16). There was a 35% probability of aggravated headaches in patients with pre-existing headaches. 

The neurotoxic adverse effects of interferon alfa may be mediated by an action at opioid receptors, and naltrexone may antagonize some of this (SEDA-20,83). Pruritus, probably mediated via enkephalins and opioids, may also be antagonized by naltrexone (SEDA-22,104). 

Adverse effects of interferon are fever, lethargy, headache and myalgia. 

Taken together, the results of these two studies suggest that these drugs may reduce the flu-like adverse effects of interferon, perhaps more so at lower doses of interferon. The clinical relevance of the measures of antiviral activity of interferon is uncertain, so the disparate effects found with paracetamol and prednisone are unclear. 

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