5 WARNINGS AND PRECAUTIONS
5.1 Risks from Concomitant Use with Opioids
Concomitant use of benzodiazepines, including XANAX XR, and opioids may result in profound sedation, respiratory depression, coma, and death. Because of these risks, reserve concomitant prescribing of these drugs in patients for whom alternative treatment options are inadequate.
Observational studies have demonstrated that concomitant use of opioid analgesics and benzodiazepines increases the risk of drug-related mortality compared to use of opioids alone. If a decision is made to prescribe XANAX XR concomitantly with opioids, prescribe the lowest effective dosages and minimum durations of concomitant use, and follow patients closely for signs and symptoms of respiratory depression and sedation. In patients already receiving an opioid analgesic, prescribe a lower initial dose of XANAX XR than indicated in the absence of an opioid and titrate based on clinical response. If an opioid is initiated in a patient already taking XANAX XR, prescribe a lower initial dose of the opioid and titrate based upon clinical response.
Advise both patients and caregivers about the risks of respiratory depression and sedation when XANAX XR is used with opioids. Advise patients not to drive or operate heavy machinery until the effects of concomitant use with the opioid have been determined [see Drug Interactions (7.1)].
5.3 Dependence and Withdrawal Reactions
Certain adverse clinical events, some life-threatening, are a direct consequence of physical dependence to XANAX XR. These include a spectrum of withdrawal symptoms; the most important is seizure [see Drug Abuse and Dependence (9.3)]. Even after relatively short-term use at doses of ≤ 4 mg/day, there is some risk of dependence. Spontaneous reporting system data suggest that the risk of dependence and its severity appear to be greater in patients treated with doses greater than 4 mg/day and for long periods (more than 12 weeks). However, in a controlled postmarketing discontinuation study of panic disorder patients who received XANAX, the duration of treatment (3 months compared to 6 months) had no effect on the ability of patients to taper to zero dose. In contrast, patients treated with doses of XANAX greater than 4 mg/day had more difficulty tapering to zero dose than those treated with less than 4 mg/day.
In a controlled clinical trial in which 63 patients were randomized to XANAX and where withdrawal symptoms were specifically sought, the following were identified as symptoms of withdrawal: heightened sensory perception, impaired concentration, dysosmia, clouded sensorium, paresthesias, muscle cramps, muscle twitch, diarrhea, blurred vision, appetite decrease, and weight loss. Other symptoms, such as anxiety and insomnia, were frequently seen during discontinuation, but it could not be determined if they were due to return of illness, rebound, or withdrawal.
Early morning anxiety and emergence of anxiety symptoms between doses of XANAX have been reported in patients with panic disorder taking prescribed maintenance doses. These symptoms may reflect the development of tolerance or a time interval between doses which is longer than the duration of clinical action of the administered dose. In either case, it is presumed that the prescribed dose is not sufficient to maintain plasma levels above those needed to prevent relapse, rebound, or withdrawal symptoms over the entire course of the interdosing interval.
5.4 Effects on Driving and Operating Machinery
Because of its CNS depressant effects, patients receiving XANAX XR should be cautioned against engaging in hazardous occupations or activities requiring complete mental alertness such as operating machinery or driving a motor vehicle. For the same reason, patients should be cautioned about the concomitant use of alcohol and other CNS depressant drugs during treatment with XANAX XR [see Drug Interactions (7.1)].
5.5 Neonatal Sedation and Withdrawal Syndrome
Use of XANAX XR during the later stages of pregnancy can result in sedation (respiratory depression, lethargy, hypotonia) and withdrawal symptoms (hyperreflexia, irritability, restlessness, tremors, inconsolable crying, and feeding difficulties) in the neonate. Observe newborns for signs of sedation and neonatal withdrawal syndrome and manage accordingly [see Use in Specific Populations (8.1)].
5.6 Interaction with Drugs that Inhibit Metabolism via Cytochrome P450 3A
The initial step in alprazolam metabolism is hydroxylation catalyzed by cytochrome P450 3A (CYP3A). Drugs that inhibit this metabolic pathway may have a profound effect on the clearance of alprazolam.
Strong CYP3A Inhibitors
XANAX XR is contraindicated in patients receiving strong inhibitors of CYP3A such as azole antifungal agents [see Contraindications (4)]. Ketoconazole and itraconazole have been shown in vivo to increase plasma alprazolam concentrations 3.98 fold and 2.70 fold, respectively.
Dosage adjustment is necessary when XANAX XR and ritonavir are initiated concomitantly or when ritonavir is added to a stable dosage of XANAX XR [see Dosage and Administration (2.5), Drug Interactions (7.1)].
Drugs demonstrated to be CYP3A inhibitors on the basis of clinical studies involving alprazolam: nefazodone, fluvoxamine, and cimetidine [see Drug Interaction (7.1), Clinical Pharmacology (12.3)]. Use caution and consider dose reduction of XANAX XR, as appropriate, during co-administration with these drugs.
5.7 Patients with Depression
Benzodiazepines may worsen depression. Panic disorder has been associated with primary and secondary major depressive disorders and increased reports of suicide among untreated patients. Consequently, appropriate precautions (e.g., limiting the total prescription size and increased monitoring for suicidal ideation) should be considered in patients with depression.
Episodes of hypomania and mania have been reported in association with the use of XANAX XR in patients with depression [see Adverse Reactions (6.1)].
5.9 Risks in Patients with Impaired Respiratory Function
There have been reports of death in patients with severe pulmonary disease shortly after the initiation of treatment with alprazolam. Closely monitor patients with impaired respiratory function. If signs and symptoms of respiratory depression, hypoventilation, or apnea occur, discontinue XANAX XR.