Important Drug-Drug Interactions for the Addiction Psychiatrist.

The misuse of illicit substances, prescribed medications, and alcohol poses obvious health risks to afflicted individuals. When addressing these health risks, the overarching concerns generally relate to the direct effects that various substances can have on the functioning of multiple organ systems: cardiac, pulmonary, central nervous system, and others. What is not always evident, but potentially equally or even more dire, are the risks arising from drug-drug interactions involving illicit drugs and alcohol, whether with each other, or with prescribed medications.

Rapid resolution of psychotic symptoms in a patient with schizophrenia using allopurinol as an adjuvant: a case report.

Context: Despite multiple trials of different adjuvant therapies to an antipsychotic regimen, there have been few promising results. Allopurinol may be one promising adjunctive therapy based on three randomized controlled trials.

Objective: To determine whether adjuvant allopurinol would be beneficial to a patient already on multiple trials of antipsychotics with no improvement.

The pharmacokinetics of paliperidone versus risperidone.

Background: Several new atypical antipsychotics have become available for use, but knowledge about their pharmacology may not be widespread.

Objective: This review aims to increase awareness and knowledge about risperidone (R) and paliperidone (9-hydroxyrisperidone [9-OHR]), their pharmacokinetics, and pharmacodynamics.

Method: The authors present a review of the literature on R and 9-OHR.

Capacity to give surgical consent does not imply capacity to give anesthesia consent: implications for anesthesiologists.

There is precedent in medicine for recognizing and accepting intact decisional capacity and the subsequent ability to provide valid consent in one treatment domain, while simultaneously recognizing that the patient lacks decisional capacity in other domains. As such, obtaining consent for anesthesia for a surgical procedure is a separate entity from obtaining consent for the surgery itself. Anesthesia for surgery and the surgical procedure itself are separate treatment domains and as such require separate consents.

Pharmacokinetic drug interactions of synthetic opiate analgesics.

Earlier reviews have covered pharmacokinetic drug interactions of natural and semi-synthetic opioid analgesics. This review will focus on the pharmacokinetic drug-drug interactions of methadone, propoxyphene, levomethadyl, meperidine, other phenylpiperidines (such as fentanyl), pentazocine, diphenoxylate, loperimide, and tramadol. The authors present an extensive review of the current literature.

A double-blind trial of adjunctive allopurinol for schizophrenia.

Objective: To investigate if adjunctive allopurinol reduces symptoms in schizophrenia outpatients with persistent symptoms despite adequate pharmacotherapy.

Method: N=59 schizophrenia outpatients were randomly assigned to receive adjunctive allopurinol 300 mg bid or identical-looking placebo for 8 weeks after a 2-week placebo run-in. Symptoms were assessed biweekly.

A preliminary attempt to personalize risperidone dosing using drug-drug interactions and genetics: part I.

Background: Personalized prescription is described even in lay journals, but there has been no attempt to propose personalizing dosing for any specific psychiatric drug.

Objective: Any attempt to develop personalized dosing needs to be anchored in our understanding of the pharmacological response of each drug in each person's environment, particularly drug-drug interactions (DDIs) and how genetic make-up influences drug response.

Method: Risperidone (R) is used as an example.

Oral contraceptives.

Nearly 50 years ago, the introduction of Enovid (norethynodrel 10 microg and mestranol 150 microg), which provided convenient and reliable contraception, revolutionized birth control. Reports of interactions between oral contraceptives (OCs) and other drugs began to trickle into the literature. At first, these drug interactions appeared to be random and unrelated.

Clozapine case series.

Clozapine is not a drug that is ever used casually. Patients generally are afflicted with severe illnesses and have demonstrated treatment resistance and/or intolerance to other therapeutic options before clozapine is seriously considered. When the clinical stakes are this high, it is especially important that physicians gain an appreciation for the various drug-drug interactions that can significantly increase or decrease clozapine blood levels; such pharmacokinetic changes can derail clozapine treatment by producing clozapine toxicity or loss of antipsychotic efficacy, respectively.

Gastrointestinal medications.

Medications to address gastrointestinal disorders are among the most commonly dispensed somatic medications. The authors examine proton pump inhibitors, H(2) blockers, 5-HT(3) receptor-antagonists, and a few other drugs that are used to address this domain of medical concerns. The metabolic pathways, interactions with the P-glycoprotein transporter, and capabilities of inhibiting or inducing metabolic enzymes are elucidated for each drug.

Unrecognized drug-drug interactions: a cause of intraoperative cardiac arrest?

Many physicians overlook, or are unaware of, most drug-drug interactions. In our patient, the local anesthetic used for an axillary block may have been the precipitating drug in a cascade of drug-drug interactions that resulted in a cardiac arrest. The combination of multiple preoperative drug-drug interactions prevented the return of a stable native cardiac rhythm for almost 24 h.

An overview of psychotropic drug-drug interactions.

The psychotropic drug-drug interactions most likely to be relevant to psychiatrists' practices are examined. The metabolism and the enzymatic and P-glycoprotein inhibition/induction profiles of all antidepressants, antipsychotics, and mood stabilizers are described; all clinically meaningful drug-drug interactions between agents in these psychotropic classes, as well as with frequently encountered nonpsychotropic agents, are detailed; and information on the pharmacokinetic/pharmacodynamic results, mechanisms, and clinical consequences of these interactions is presented. Although the range of drug-drug interactions involving psychotropic agents is large, it is a finite and manageable subset of the much larger domain of all possible drug-drug interactions.

The Schizophrenia Patient Outcomes Research Team (PORT): updated treatment recommendations 2003.

Since publication of the original Schizophrenia Patient Outcomes Research Team (PORT) treatment recommendations in 1998, considerable scientific advances have occurred in our knowledge about how to help persons with schizophrenia. Today an even stronger body of research supports the scientific basis of treatment. This evidence, taken in its entirety, points to the value of treatment approaches combining medications with psychosocial treatments, including psychological interventions, family interventions, supported employment, assertive community treatment, and skills training.

Six patterns of drug-drug interactions.

The literature on pharmacokinetic drug-drug interactions usually focuses on various interactions relating to the cytochrome p450 system, phase II glucuronidation, and P-glycoprotein function. However, there has been relatively little examination of how the modes or patterns that govern these interactions can be systematically characterized to better anticipate drug-drug interactions in clinical practice. This article details a schema of six core patterns of pharmacokinetic drug-drug interaction relating to processes of induction and inhibition and the action of substrates.