Special Populations

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The presence of certain life circumstances or comorbid medical or psychosocial conditions warrant special attention during the evaluation and treatment of opioid addiction with buprenorphine. Patients with circumstances or conditions that require special attention include those with certain medical comorbidities (e.g., AIDS, tuberculosis), concurrent mental disorders, or concurrent alcohol or other substance abuse disorders, as well as pregnant women, adolescents, geriatric patients, patients under the jurisdiction of the criminal justice system, and healthcare professionals who are addicted. Because of the unique issues presented by these circumstances, addiction treatment for these patients may require additional training or specialty care and consultation. Before treating individuals with these circumstances for opioid addiction in an office setting, physicians should consider whether patient needs can be met with the resources at hand or if referral to specialized treatment programs or to addiction specialists is indicated.

Patients With Medical Comorbidities

Patients addicted to opioids who present for treatment often have other comorbid medical problems. These conditions are often a consequence of high-risk behaviors, including injection drug use (intravenous, intramuscular, or subcutaneous), or of the direct toxic effects of the active and inert ingredients in illicit drugs.

Co-Occuring Medical Problems

People addicted to opioids often present with other medical problems including:

*  HIV/AIDS
*  Tuberculosis
*  Hepatitis B and C
*  Skin and Soft Tissue Infections
*  Syphilis and other Sexually Transmitted Diseases
*  Seizure Disorders
*  Valvular Heart Disease Secondary to Endocarditis
*  Pulmonary Hypertension Secondary to Talc Granulomatosis
*  Pseudoaneurysms of the neck and groin secondary to thromboplebitis
*  Lymphedema
*  Renal insufficiency secondary to heroin-associated nephropathy

Patients with a history of hepatitis C may require hepatitis A and B vaccinations and may be intolerant of potentially hepatotoxic medications. One retrospective study found that liver function tests were significantly elevated in patients treated with buprenorphine who also had a history of hepatitis, suggesting that liver function tests should be monitored in these patients on a regular  basis  during   buprenorphine  treatment  (Petry   et  al. 2000). A detailed discussion of medical comorbidities in addiction is beyond the scope of this chapter and is reviewed extensively elsewhere (Cherubin and Sapira 1993; Stein 1990).

Treatment of opioid addiction in patients with comorbid medical conditions is likely to result in better outcomes for the comorbid conditions than would be achieved in the absence of treatment of the substance use disorder. Moatti et al. (2000) found that patients on buprenorphine tended to be more compliant with highly active antiretroviral therapies (HAART) than patients who were not treated concurrently for opioid addiction.

Pharmacological treatments of comorbid medical disorders may have important drug interactions with buprenorphine due to shared pharmacokinetic properties. Although Carrieri et al. (2000) found no detrimental short-term effect of buprenorphine treatment on the effect of HAART on viral load, buprenorphine is metabolized by the hepatic cytochrome P450 3A4 enzyme system and will likely interact with other medications metabolized by the same system.

Certain antiretrovirals may occupy the cytochrome P450 3A4 system and thus inhibit the metabolism of buprenorphine. Other drugs that induce the cytochrome P450 3A4 system (e.g., certain antituberculosis, anticonvulsant, and antiretroviral medications) may decrease serum concentrations of buprenorphine, resulting in opioid withdrawal or decreased effectiveness. Because the interactions of most medications with buprenorphine have not been systematically studied, physicians should monitor for any signs or symptoms of opioid side effects, loss of effectiveness, or withdrawal after a patient starts any new medications.

 Buprenorphine dose adjustments may be necessary after starting new medications, even for patients who have been on a stable maintenance dose.

Other potential, and as yet unknown, drug interactions include the possibility of buprenorphine increasing or decreasing metabolism of medications used in treating comorbid medical conditions. Informing patients of potential drug–drug interactions, especially sedation or precipitated opioid withdrawal, is important to prevent jeopardizing adherence with medical treatment and/or precipitating relapse to illicit opioid use.

In summary, it is important to screen for and manage common comorbid medical conditions in patients being treated with buprenorphine for opioid addiction and to anticipate known and potential drug interactions.

 References:  Clinical Guidelines For The Use of Buprenorphine In The Treatment of Treatment  Of Opioid Addiction TIP 40 (Chapter 5)

Written And Edited By: Deborah Shrira           Dated: 8 May 2007