Carbamazepine increases cerebrospinal fluid thyrotropin-releasing hormone levels in affectively ill patients

Carbamazepine

This chapter includes the aspects of carbamazepine. The drug is synthesized by the use of 5H-dibenz[b,f]azepine and phosgene followed by subsequent reaction with ammonia. Carbamazepine is generally used for the treatment of seizure disorders and neuropathic pain, it is also important as off-label for a second-line treatment for bipolar disorder and in combination with an antipsychotic in some cases of schizophrenia when treatment with a conventional antipsychotic alone has failed. Other uses may include attention deficit hyperactivity disorder, schizophrenia, phantom limb syndrome, complex regional pain syndrome, borderline personality disorder, and posttraumatic stress disorder. The chapter discusses the drug metabolism and pharmacokinetics and presents various methods of analysis of this drug such electrochemical analysis, spectroscopic analysis, and chromatographic techniques of separation. It also discusses its physical properties such as solubility characteristics, X-ray powder diffraction pattern, and thermal methods of analysis. The chapter is concluded with a discussion on its biological properties such as activity, toxicity, and safety.

Thirty years of clinical experience with carbamazepine in the treatment of bipolar illness: principles and practice

Carbamazepine began to be studied in a systematic fashion in the 1970s and became more widely used in the treatment of bipolar disorder in the 1980s. Interest in carbamazepine has been renewed by (i) the recent US FDA approval of a long-acting preparation for the treatment of acute mania; (ii) studies suggesting some efficacy in bipolar depression; and (iii) evidence of prophylactic efficacy in some difficult-to-treat subtypes of bipolar illness. A series of double-blind controlled studies of the drug were conducted at the US National Institute of Mental Health from the mid-1970s to the mid-1990s. This review summarises our experience in the context of the current literature on the clinical efficacy, adverse effects and pharmacokinetic interactions of carbamazepine. Carbamazepine has an important and still evolving place in the treatment of acute mania and long-term prophylaxis. It may be useful in individuals with symptoms that are not responsive to other treatments and in some subtypes of bipolar disorder that are not typically responsive to a more traditional agent such as lithium. These subtypes might include those patients with bipolar II disorder, dysphoric mania, substance abuse co-morbidity, mood incongruent delusions, and a negative family history of bipolar illness in first-degree relatives. In addition, carbamazepine may be useful in patients who do not adequately tolerate other interventions as a result of adverse effects, such as weight gain, tremor, diabetes insipidus or polycystic ovarian syndrome. We review our clinical and research experience with carbamazepine alone and in combination with lithium, valproic acid and other agents in complex combination treatment of bipolar illness. More precise clinical and biological predictors and correlates of individual clinical responsiveness to carbamazepine and other mood stabilisers are eagerly awaited.

Chronic ethanol or glucose consumption alter TRH content and pyroglutamyl aminopeptidase II activity in rat limbic regions

Thyrotropin-releasing hormone (TRH), its receptors and inactivating enzyme (PPII) are present in limbic regions. Nutritional changes or acute ethanol administration in male rats differentially modulate TRH or PPII expression. Chronic ethanol effect was studied in male (3, 6 and 8 weeks) and female rats (6 weeks) including naive and pair-fed (glucose) groups. Daily solid food and liquid intake, serum TSH and corticosterone, TRH content and PPII activity in limbic regions, were quantified. Gender differences were found in ethanol and total caloric intake and body weight gain, TSH and corticosterone levels. Ethanol consumption decreased TRH content and PPII activity in frontal cortex of male rats after 3-6 weeks. In contrast, glucose ingestion altered, by the third week, TRH content in amygdala, hippocampus, hypothalamus and nucleus accumbens, PPII activity in hippocampus and frontal cortex; by the sixth week, TRH content in amygdala and n. accumbens of male and females. Withdrawal at 24 h after 3-week ethanol ingestion decreased TRH content in amygdala and PPII activity in n. accumbens, while withdrawal from glucose reverted some of the effects produced by chronic glucose ingestion. Variations in TRH content or PPII activity support a region specific involvement of TRH neurons that depend on the treatment.

Thyrotropin-releasing hormone in the treatment of intractable epilepsy

Intractable seizures remain a significant therapeutic challenge despite current advances in the treatment of epilepsy. Thyrotropin-releasing hormone, the first neuroendocrine releasing factor to be isolated and fully characterized, was also the first releasing factor investigated as a possible neurotransmitter/neuromodulator outside the hypothalamus. Basic and clinical research has revealed a distinct neuroanatomic distribution and a neurochemical role for thyrotropin-releasing hormone in seizure modulation. Thyrotropin-releasing hormone and selected analogs were reported to have antiepileptic effects in several animal seizure paradigms, including kindling and electroconvulsive shock. Clinically, thyrotropin-releasing hormone treatment has been reported to be efficacious in such intractable epilepsies as infantile spasms, Lennox-Gastaut syndrome, myoclonic seizures, and other generalized and refractory partial seizures. Herein, we review evidence that suggests that thyrotropin-releasing hormone and selected thyrotropin-releasing hormone analogs may represent a new class of novel antiepileptic drugs, namely, antiepileptic neuropeptides and provide insights into potential new treatments for the intractable epilepsies.