I read with great interest the recent article by Nachega et al. (2013). Interestingly, one common cause of psychiatric symptoms in HIV patients that is often overlooked is efavirenz therapy.
Nearly 13% of patients on efavirenz therapy discontinue the drug secondary to its adverse psychiatric effects (Hasse et al. 2005). Psychiatric symptoms are reported by more than half of all patients on efavirenz therapy. Pérez-Molina (2002) have reported a much higher rate of psychiatric symptoms, in almost 73% of HIV patients on efavirenz therapy. CYP2B6-G516T polymorphisms have a significant influence on the clearance of efavirenz. For instance, Lowenhaupt et al. (2007) reported the case of a patient with a heterozygous gene polymorphism of CYP2B6-G516T, who developed accentuated efavirenz concentrations leading to subsequent psychosis. Among these polymorphisms, 36% are GG and 23% are of the TT subtype. Significantly, higher efavirenz levels have been noted in patients with TT polymorphisms. As a result, patients with TT polymorphisms are more predisposed to develop psychiatric symptoms (van Twillert et al. 2005). Efavirenz clearance is genetically attenuated in Afro-Americans, especially women, and thereby this group is at a higher risk of developing efavirenz-induced psychosis. Efavirenz-induced psychosis has been reported in patients as young as 12 years of age. The general consensus is that efavirenz may alter cytokine levels that may contribute to the development of these psychiatric symptoms (Salter & Patel 2009). The CD4 lymphocyte counts as well as the ‘viral load’ have a significant influence on the severity of these psychiatric effects. Interestingly, coinfection with hepatitis B greatly accentuates the risk of developing psychiatric adverse effects.
Psychiatric symptoms usually appear after the first dose and progressively get worse. Psychosis is seen in 2% of patients on efavirenz therapy (Wintergerst et al. 2008). Interestingly, CYP2B6-G516T polymorphisms also influence the appearance and incidence of side effects of efavirenz. For instance, 30% of patients on efavirenz therapy report increased irritability. Patients may present with schizophreniform disease. Psychotic symptoms may appear as much as 3 years after initiation of efavirenz therapy (Velasco et al. 2011). Some patients may present with accentuated anxiety. Paranoid hallucinations as well as delusions are often reported. The incidence of psychosis among children on efavirenz therapy is around 3.0%. Homicidal acts may worsen the scenario. Gutiérrez et al. (2005) have also reported the development of obsessive symptoms secondary to efavirenz therapy. Both insomnia (28.3%) and hypersomnolence (25%) have been reported (Zalila et al. 2010). Nightmares and abnormal dreams are increased in frequency and are reported by 48.3% of the patients. Wintergerst et al. (2008) reported that 15.1% of children on efavirenz therapy report concentration problems. The corresponding number for adults is 26.7% (Sabbatani et al. 2002). 30% of the patients report increased anxiety and nervousness. Symptoms are most marked 2 weeks after initiation of therapy and usually last for 4 weeks. Complications noted later during efavirenz therapy include depression. Mildly impaired psychological alterations may persist for as long as 2 years. Simultaneous use of illicit drugs accentuates the propensity of developing psychiatric symptoms.
Given the high incidence of psychiatric complications, all patients to be started on efavirenz therapy should be evaluated for any psychiatric abnormalities. While on efavirenz therapy, serum levels of efavirenz should be routinely monitored. Interestingly, cyproheptadine has recently been shown to be effective in ameliorating and mitigating the neuropsychiatric symptoms of efavirenz therapy (Mills et al. 2013). Cyproheptadine has a significant impact on decreasing efavirenz-induced accentuation of both the ‘Beck Depression Scale’ scores as well as the ‘Hamilton Depression Rating Scale’ scores. A similar reduction is seen in the ‘Positive and Negative Syndrome Scale’ scores. In addition, before initiating efavirenz therapy, cytochrome P450 gene variant testing is advised (Dabaghzadeh et al. 2012).
These reports illustrate the significant psychiatric side effects of efavirenz and the need to watch out for these symptoms.