Medical - Opioid Use Disorders

Medical

Medical comorbidity is a major problem among persons with opioid dependence; HIV infection, AIDS, and hepatitis B and C have become some of the most common problems. Sharing injec-tion equipment including “cookers” and rinse water, or engaging in high-risk sexual behaviors are the main routes of infection. Sexual transmission appears to be a more common route of HIV transmission among females than males because the HIV virus is spread more readily from males to females than from females to males. Females who are intravenous drug users and also engage in prostitution or other forms of high-risk sex are at extremely high risk for HIV infection Cocaine use has been found to be a significant risk factor as a single drug of abuse or when used in combination with heroin or other opioids (Booth et al., 2000).

Recent studies have identified several important interactions between methadone and drugs to treat HIV. One important inter-action is that methadone increases plasma levels of zidovudine; the associated symptoms resemble methadone withdrawal. There have been instances in which methadone doses have been increased in response to complaints of withdrawal with increasing doses com-pounding the problem. Another important interaction involves decreased methadone blood levels secondary to nevirapine that may result in mild to moderate withdrawal. This interaction can be important if the patient is taken off either of these two drugs while on methadone, since the result may be a sudden rise in methadone blood levels with signs and symptoms of over medication.

As mentioned earlier, mortality is high and studies have found annual death rates of approximately 10 per 1000 or greater, which is substantially higher than demographically matched samples in the general population (Gronbladh et al., 1990). Com-mon causes of death are overdose, accidents, injuries, and medi-cal complications such as cellulitis, hepatitis, AIDS, tuberculosis and endocarditis. The cocaine and alcohol dependence that is often seen among opioid-dependent persons contributes to cir-rhosis, cardiomyopathy, myocardial infarction and cardiac ar-rhythmias. Tuberculosis has become a particularly serious prob-lem among intravenous drug users, especially heroin addicts. In most cases, infection is asymptomatic and evident only by the presence of a positive tuberculin skin test. However, many cases of active tuberculosis have been found, especially among those who are infected with HIV.

Other medical complications of heroin dependence are seen in children born to opioid-dependent women. Perhaps the most serious is premature delivery and low birthweight, a problem that can be reduced if the mother is on methadone maintenance and receiving prenatal care. Another is physiological dependence on opioids, seen in about half the infants born to women maintained on methadone or dependent on heroin or other opioids. Effective treatments for neonatal withdrawal are available and long-term adverse effects of opioid withdrawal have not been demonstrated. A recent study found that methadone is present in the breast milk of women maintained on doses as high as 180 mg but that the concentration is very low and no adverse effects were observed in the infants (McCarthy and Posey, 2000). HIV infection is seen in about one-third of infants born to HIV-positive mothers, but can be reduced to about 10% if HIV-positive pregnant women are given zidovudine prior to delivery. HIV can also be trans-mitted by breast-feeding, and thus formula is recommended for HIV-positive mothers with the exception of countries where it is unavailable or unaffordable. Thorough washing of infants born to HlV-infected mothers immediately after delivery also appears to reduce the incidence of HIV infection.