Differential pharmacokinetic drug-drug interaction potential of eletriptan between oral and subcutaneous routes

1. Pharmacokinetic drug-drug interaction (DDI) data is important from a label claim either in combination drug usage or in polypharmacy situation. 2. Eletriptan undergoes first pass related metabolism through CYP3A4 enzyme to form pharmacologically active N-desmethyl metabolite. 3. Differential DDI interaction of the concomitant oral dosing of ketoconazole (20.1 mg/kg), a CYP3A4 inhibitor, with oral (4.2 mg/kg) or subcutaneous dose (2.1 mg/kg) of eletriptan was evaluated in male Sprague Dawley rats. Serial pharmacokinetic samples were collected and simultaneously analysed for eletriptan/N-desmethyl eletriptan using validated assay. Non-compartmentally derived pharmacokinetic parameters for various treatments were analysed statistically. 4. After oral eletriptan in presence of ketoconazole, C_max (40 vs. 32 ng/mL alone) and AUC_inf (81 vs. 24 ng.h/mL alone) of eletriptan increased; the formation of N-desmethyl eletriptan decreased (C_max=1.1 ng/mL, 3.9%) with ketoconazole as compared to without treatment (C_max=3.7 ng/mL, 11.2%). After subcutaneous eletriptan in presence of ketoconazole, there was no change in C_max (153 vs.152 ng/mL) or AUC_inf (267 vs. 266 ng.h/mL) of eletriptan. Formation of N-desmethyl eletriptan after the subcutaneous dose was determined at few intermittent time points with/without ketoconazole. 5. Preclinical data support differential DDI of eletriptan when dosed oral vs. subcutaneous, which need to be evaluated in a clinical setting.

Acute and chronic triptan exposure neither alters rodent cerebral blood flow nor worsens ischemic brain injury

Although it is still debated whether vasoconstriction underlies migraine resolution by triptans, they are not recommended in patients at cardiovascular risk. However, relationship between stroke incidence and triptan use is unclear, and it is unknown whether acute or chronic use of these drugs worsens ischemic brain injury. To address this issue, we investigated the effect of clinically-relevant doses of the potent cerebral artery vasoconstrictor eletriptan on cerebral blood flow (CBF) and brain infarct volumes, as well as on expression of genes involved in cerebrovascular regulation. We report that acute treatment of rats or mice with eletriptan did not reduce basal CBF, which promptly dropped upon treatment with prazosin or dihydroergotamine. Acute of chronic (1month) eletriptan also did not affect CBF changes and infarct volumes in mice undergoing brain ischemia/reperfusion. Finally, chronic eletriptan reduced brain mRNAs for PACAP and VIP, leaving unaffected those for 5HT1_B/DR and CGRP. No significant transcript changes were found in dura mater. Data suggest that the impact of triptans on cerebral hemodynamic should be re-evaluated, as well as their propensity to increase stroke risk in migraineurs.

Eletriptan in the management of acute migraine: an update on the evidence for efficacy, safety, and consistent response

Migraine is a multifactorial, neurological and disabling disorder, also characterized by several autonomic symptoms. Triptans, selective serotonin 5-HT1B/1D agonists, are the first-line treatment option for moderate-to-severe headache attacks. In this paper, we review the recent data on eletriptan clinical efficacy, safety, and tolerability, and potential clinically relevant interactions with other drugs. Among triptans, eletriptan shows a consistent and significant clinical efficacy and a good tolerability profile in the treatment of migraine, especially for patients with cardiovascular risk factors without coronary artery disease. It shows the most favorable clinical response, together with sumatriptan injections, zolmitriptan and rizatriptan. Additionally, eletriptan shows the most complex pharmacokinetic/dynamic profile compared with the other triptans. It is metabolized primarily by the CYP3A4 hepatic enzyme and therefore the concomitant administration of CYP3A4-potent inhibitors should be carefully evaluated. A relatively low risk of serotonin syndrome is given by the co-administration with serotoninergic drugs. No clinically relevant interaction has been found with drugs used for migraine prophylactic treatment or other acute drugs, with the exception of ergot derivatives that should not be co-administered with eletriptan.

Outcome for headache and pain-free nonresponders to treatment of the first attack: a pooled post-hoc analysis of four randomized trials of eletriptan 40 mg

OBJECTIVE

The objective of this article is to evaluate, in first attack eletriptan headache and pain-free nonresponders, the efficacy of treating a second and third attack with the same dose of eletriptan 40 mg (ELE-40).

METHODS

Data were pooled from four randomized, double-blind, placebo-controlled, multiple attack studies of eletriptan in the treatment of migraine. The first-attack eletriptan headache (HNR) and pain-free (PFNR) nonresponder samples consisted of patients who did not achieve headache or pain-free responses at two hours, or sustained headache or pain-free responses at 24 hours. The efficacy of the same dose of eletriptan (vs placebo; PBO) in treating the second and third attacks was evaluated using a logistic regression model.

RESULTS

Among Attack 1 eletriptan HNRs, treatment with ELE-40 (vs PBO) was associated with significantly higher two-hour headache response and pain-free rates, respectively, on both Attack 2 (48.8% vs 20.2%; 17.0% vs 3.9%; P  < 0.0001 for both comparisons) and Attack 3 (37.4% vs 15.5%; 18.8% vs 3.2%; P  < 0.0001 for both comparisons). Significantly higher sustained headache response and pain-free rates at 24 hours were also observed on both Attack 2 and Attack 3.

CONCLUSIONS

The results of this pooled analysis suggest that patients who have HNR or PFNR to an initial dose of eletriptan may respond when a second and third attack is treated with the same dose.

Synthesis of compounds related to the anti-migraine drug eletriptan hydrobromide

Eletriptan hydrobromide (1) is a selective serotonin (5-HT(1)) agonist, used for the acute treatment of the headache phase of migraine attacks. During the manufacture of eletriptan hydrobromide the formation of various impurities were observed and identified by LC-MS. To control the formation of these impurities during the preparation of active pharmaceutical ingredients, the structure of the impurities must be known. Major impurities of the eletriptan hydrobromide synthesis were prepared and characterized by using various spectroscopic techniques, i.e., mass spectroscopy, FTIR , (1)H NMR, (13)C NMR/DEPT, and further confirmed by co-injection in HPLC. The present study will be of great help in the synthesis of highly pure eletriptan hydrobromide related compounds.

Two chromatographic methods for the determination of some antimigraine drugs

Two stability indicating chromatographic methods were proposed for the determination of almotriptan, eletriptan, and rizatriptan, in presence of their acid degradation products. The first method is a quantitative densitometric thin layer chromatography. The developing systems were; acetonitrile: methanol: dichloromethane: ammonia (10:6:3:1 v/v), ethyl acetate: methanol: ammonia (15:4:1 v/v), and methanol: acetonitrile: ammonia (9:4:1 v/v) for almotriptan, eletriptan and rizatriptan respectively. The TLC plates were scanned at 235 nm. Linear relationships were obtained over concentration ranges (5–50 μg/spot) for almotriptan and rizatriptan, and (5–60 μg/spot) for eletriptan. The second method based on the separation and determination of the studied drugs, using RP-HPLC technique. The separation was achieved on C18 Hypersil column, elution was carried out using phosphate buffer pH 3: methanol: acetonitrile (2: 1:1 v/v) at flow rate 2 mL/min and UV detection at 235 nm. Linear relationships were obtained over concentration ranges (10–200 μg/mL) for almotriptan and eletriptan, and (10–180 μg/mL) for rizatriptan. The chromatographic methods were successfully applied for the determination of each of the studied drugs in pure form, tablet form, and in laboratory prepared mixtures with their acid degradation products.