Purpose: The limitations of current US Food and Drug Administration (FDA)eapproved medications for the treatment of attention-deficit/hyperactivity disorder (ADHD) set the need for the development of novel, effective, and tolerable medications to treat this disorder. The purpose of this study was to evaluate whether treatment with SPN-812 (viloxazine extended-release) significantly reduces symptoms of ADHD in children. Methods: This study was a randomized, doubleblind, placebo-controlled 6-week trial to assess the efficacy and safety of once-daily 100-and 200-mg SPN-812 in the treatment of ADHD in male and female children 6e11 years of age. Inclusion criteria required subjects to have a confirmed Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, ADHD diagnosis, an ADHD-Rating Scale-5 (ADHD-RS-5) score 28, a Clinical Global Impression-Severity score 4, and for subjects to be free of ADHD medication 1 week before randomization. The primary efficacy endpoint was the change from baseline (CFB) at end of study (EOS) in ADHD-RS-5 Total score. Key secondary endpoints included Clinical Global Impression-Improvement (CGI-I) scores at EOS and CFB at EOS in the Conners 3eParent Short Form (Conners 3ePS) Composite T-score and the Weiss Functional Impairment Rating ScaleeParent (WFIRSeP) Total average score. Safety assessments included adverse events (AEs), laboratory tests, vital signs, physical examinations, ECGs, and the Columbia-Suicide Severity Rating Scale. The primary efficacy endpoint was analyzed by using a mixed model for repeated measures; all secondary measures were analyzed by using an ANCOVA model. Results: A total of 477 subjects were randomized to treatment (intent-to-treat population, n ¼ 460). The majority of subjects were male (63%) and either White (51.3%) or African American (43.7%). The demographic and baseline characteristics between the groups were similar. Statistically significant improvements in ADHD-RS-5 Total score were observed in both the 100-and 200-mg/day SPN-812 treatment groups compared to placebo at week 1 of treatment (P ¼ 0.0004 and P ¼ 0.0244, respectively), which was maintained through EOS (P ¼ 0.0004 and P < 0.0001). Significant improvements were also observed at EOS in the CGI-I scale (P ¼ 0.0020 and P < 0.0001), Conners 3ePS Composite T-score

Topiramate is effective as monotherapy in adults and children. Because a therapeutic effect emerges during titration, clinicians should adjust dosages in step-wise fashion with intermediate stopping points, e.g., 100 mg/day, to evaluate patient response and achieve the optimal maintenance dosage.

Topiramate is a new antiepileptic drug (AED) that has been approved worldwide (in more than 80 countries) for the treatment of various kinds of epilepsy. It is currently being evaluated for its effect in various neurological and psychiatric disorders. The pharmacokinetics of topiramate are characterised by linear pharmacokinetics over the dose range 100-800 mg, low oral clearance (22-36 mL/min), which, in monotherapy, is predominantly through renal excretion (renal clearance 10-20 mL/min), and a long half-life (19-25 hours), which is reduced when coadministered with inducing AEDs such as phenytoin, phenobarbital and carbamazepine. The absolute bioavailability, or oral availability, of topiramate is 81-95% and is not affected by food. Although topiramate is not extensively metabolised when administered in monotherapy (fraction metabolised approximately 20%), its metabolism is induced during polytherapy with carbamazepine and phenytoin, and, consequently, its fraction metabolised increases. During concomitant treatment with topiramate and carbamazepine or phenytoin, the (oral) clearance of topiramate increases 2-fold and its half-life becomes shorter by approximately 50%, which may require topiramate dosage adjustment when phenytoin or carbamazepine therapy is added or discontinued. From a pharmacokinetic standpoint, topiramate is a unique example of a drug that, because of its major renal elimination component, is not subject to drug interaction due to enzyme inhibition, but nevertheless is susceptible to clinically relevant drug interactions due to induction of its metabolism. Unlike old AEDs such as phenytoin and carbamazepine, topiramate is a mild inducer and, currently, the only interaction observed as a result of induction by topiramate is that with ethinylestradiol. Topiramate only increases the oral clearance of ethinylestradiol in an oral contraceptive at high dosages (>200 mg/day). Because of this dose-dependency, possible interactions between topiramate and oral contraceptives should be assessed according to the topiramate dosage utilised. This paper provides a critical review of the pharmacokinetic interactions of topiramate with old and new AEDs, an oral contraceptive, and the CNS-active drugs lithium, haloperidol, amitriptyline, risperidone, sumatriptan, propranolol and dihydroergotamine. At a daily dosage of 200 mg, topiramate exhibited no or little (with lithium, propranolol and the amitriptyline metabolite nortriptyline) pharmacokinetic interactions with these drugs. The results of many of these drug interaction studies with topiramate have not been published before, and are presented and discussed for the first time in this article.

Hyponatremia, an electrolyte disturbance usually without clinical significance, may sometimes lead to serious complications when overlooked or not treated appropriately. One cause of hyponatremia, the syndrome of inappropriate antidiuretic hormone (SIADH) secretion, has been associated with some drugs, including carbamazepine (CBZ). Because of its antidiuretic effects, CBZ has been used successfully to treat diabetes insipidus centralis. Possible mechanisms for the antidiuretic effects of CBZ have been proposed. Altered sensitivity to serum osmolality by the hypothalamic osmoreceptors appears likely, but an increased sensitivity of the renal tubules to circulating ADH cannot be excluded. CBZ has led to hyponatremia in patients with epilepsy, neuralgia, mental retardation, and psychiatric disorders with a frequency varying from 4.8 to 40%. Oxcarbazepine (OCBZ), which is structurally related to CBZ, has shown similar hyponatremic effects, but whether hyponatremia occurs more often than with CBZ is not yet clear. Experience with OCBZ is still limited, and there is no definite explanation for a possible difference in antidiuretic potency. Most patients with CBZ/OCBZ-induced hyponatremia are asymptomatic. In rare cases, water intoxication has been reported, necessitating treatment discontinuation.

Summary:Purpose: To study the pharmacokinetics of a combination oral contraceptive (OC) containing norethindrone and ethinyl estradiol during OC monotherapy, concomitant OC and topiramate (TPM) therapy, and concomitant OC and carbamazepine (CBZ) therapy in order to comparatively evaluate the pharmacokinetic interaction, which may cause contraceptive failure.Methods: This randomized, open-label, five-group study included two 28-day cycles. Five groups of female subjects received oral doses of ORTHO-NOVUM 1/35 alone (cycle 1) and then concomitant with TPM or CBZ (cycle 2). The treatment groups were group 1, TPM, 50 mg/day; group 2, TPM, 100 mg/day; group 3, TPM, 200 mg/day; group 4, TPM, 200 mg/day (obese women); and group 5, CBZ, 600 mg/day. Group 4 comprised obese women whose body mass index (BMI) was between 30 and 35 kg/m 2 . The BMI of the remaining four groups was Յ27 kg/m 2 .Results: Coadministration of TPM at daily doses of 50, 100, and 200 mg (nonobese) and 200 mg (obese) nonsignificantly (p > 0.05) changed the mean area under the curve (AUC) of ethinyl estradiol by -12%, +5%, -11%, and -9%, respectively, compared with OC monotherapy. A similar nonsignificant difference was observed with the plasma levels and AUC values of norethindrone (p > 0.05). CBZ (600 mg/day) significantly (p < 0.05) decreased the AUC values of norethindrone and ethinyl estradiol by 58% and 42%, respectively, and increased their respective oral clearance by 69% and 127% (p < 0.05). Because CBZ induces CYP 3A-mediated and glucuronide conjugation metabolic pathways, the significant increase in the oral clearance of ethinyl estradiol and norethindrone was anticipated. Conclusions: TPM, at daily doses of 50-200 mg, does not interact with an OC containing norethindrone and ethinyl estradiol. The lack of the TPM-OC interaction is notable when it is compared with the CBZ-OC interaction.

Purpose: SPN-812 (viloxazine extended-release) is under investigation for the treatment of attentiondeficit/hyperactivity disorder (ADHD) in children and adolescents. This Phase III study evaluated the efficacy and tolerability of SPN-812 200 and 400 mg once daily in children 6e11 years of age with ADHD. Methods: Patients were randomly assigned to receive SPN-812 200 mg, SPN-812 400 mg, or placebo, once daily for 8 weeks (including 3 weeks titration period). The primary efficacy endpoint was the change from baseline (CFB) in ADHD Rating Scale (RS)-5 Total score at end of study (EOS). Key secondary endpoints included Clinical Global ImpressioneImprovement (CGI-I) score at EOS, CFB in Conners 3eParent Short Form (PS) composite Tscore at EOS, and CFB in Weiss Functional Impairment Rating ScaleeParent (WFIRS-P) Total average score at EOS. Findings: A total of 313 patients were enrolled, with 301 in the intent-to-treat population (194 boys, 107 girls; mean age [SD], 8.4 [1.7] years). At EOS, the CFBs in ADHD-RS-5 Total score and CGI-I score were significantly improved with both 200-and 400mg/d SPN-812 versus placebo (ADHD-RS-5, P ¼ 0.0038 and 0.0063, respectively; CGI-I, P ¼ 0.0028 and 0.0099). At EOS, the CFB in Conners 3-PS composite T-score was significantly improved with 200-(P ¼ 0.0064), but not 400-mg/ d (P ¼ 0.0917), SPN-812 compared to placebo. No significant difference between the groups was found in WFIRS-P Total average score. The rate of discontinuations due to adverse events in both SPN-812 treatment groups combined was <5%. Implications: SPN-812 200 and 400 mg once daily was associated with improvements in ADHD symptoms in school-aged children and was generally well tolerated. ClinicalTrials.gov identifier: NCT03247543.

Background: Viloxazine was historically described as a norepinephrine reuptake inhibitor (NRI). Since NRIs have previously demonstrated efficacy in attention deficit/hyperactivity disorder (ADHD), viloxazine underwent contemporary investigation in the treatment of ADHD. Its clinical and safety profile, however, was found to be distinct from other ADHD medications targeting norepinephrine reuptake. Considering the complexity of neuropsychiatric disorders, understanding the mechanism of action (MoA) is an important differentiating point between viloxazine and other ADHD medications and provides pharmacology-based rationale for physicians prescribing appropriate therapy. Methods: Viloxazine was evaluated in a series of in vitro binding and functional assays. Its effect on neurotransmitter levels in the brain was evaluated using microdialysis in freely moving rats. Results: We report the effects of viloxazine on serotoninergic (5-HT) system. In vitro, viloxazine demonstrated antagonistic activity at 5-HT 2B and agonistic activity at 5-HT 2C receptors, along with predicted high receptor occupancy at clinical doses. In vivo, viloxazine increased extracellular 5-HT levels in the prefrontal cortex (PFC), a brain area implicated in ADHD. Viloxazine also exhibited moderate inhibitory effects on the norepinephrine transporter (NET) in vitro and in vivo, and elicited moderate activity at noradrenergic and dopaminergic systems. Conclusion: Viloxazine's ability to increase 5-HT levels in the PFC and its agonistic and antagonistic effects on certain 5-HT receptor subtypes, which were previously shown to suppress hyperlocomotion in animals, indicate that 5-HT modulating activity of viloxazine is an important (if not the predominant) component of its MoA, complemented by moderate NET inhibition. Supported by clinical data, these findings suggest the updated psychopharmacological profile of viloxazine can be best explained by its action as a serotonin norepinephrine modulating agent (SNMA).

Supplemental digital content is available in the text.