Renal Infarction During the Use of Rizatriptan and Zolmitriptan: Two Case Reports

Acute coronary syndrome and transient global amnesia with sumatriptan

Triptans are potent serotoninergic vasoconstrictors. They are generally avoided in elderly patients age greater than 65 or in patients with a history of CAD. Although there are reported cases of Acute Coronary Syndrome (ACS) or Transient Global Amnesia (TGA) in patients after ingesting therapeutic doses of triptan or dihydroergotamine, this is the first case report, up to our knowledge, of a patient, who had no previous cardiac history, that was diagnosed with both ACS and TGA. A 59-year-old woman with a long-standing history of migraine, gastroesophageal reflux disease, and hypothyroidism, presented to the Emergency Department (ED) complaining of amnesia, chest pain, and left arm numbness after ingesting a single dose of oral sumatriptan approximately 1-2 h prior to arrival. She had no recollection of the events that occurred after taking sumatriptan. No acute laboratory abnormalities were found except for an elevated troponin, which continued to trend upwards. Her EKG had no ST-T wave abnormalities. She was diagnosed with Acute Coronary Syndrome (ACS), non-ST elevation MI. She had a negative noncontrast CT head. Neurology was consulted for her amnesia and diagnosed her with Transient Global Amnesia (TGA). They recommended discontinuing sumatriptan and beginning topiramate as a prophylactic therapy. There is an increasing number of reports delineating sumatriptan's adverse effects. Emergency medicine physicians should promptly recognize the toxic effects and adverse reactions from triptans. Sumatriptan-induced vasoconstriction may lead to cardiac and cerebral ischemic events.

Metabolic activation of zolmitriptan mediated by CYP2D6

Zolmitriptan (ZOL), a member of triptans, has been used for the treatment of migraine with definite therapeutic effects. However, several cases of liver injury associated with ZOL have been reported and the underlying mechanisms remain unclear.The present study aimed to investigate the metabolic activation of ZOL in vitro and in vivo. ZOL-derived glutathione (GSH) and N-acetyl cysteine (NAC) conjugates were detected in rat liver microsomal incubations. In addition, the GSH and NAC conjugates were also found in bile and urine of rats given ZOL, respectively.ZOL-derived GSH conjugate M1 was also observed in ZOL-treated rat primary hepatocytes, and the formation of M1 was inhibited by pre-cultured with quinidine (a selective inhibitor of CYP2D6). Combining with recombinant P450 enzymes incubations, we found that CYP2D6 was the predominant enzyme responsible for the metabolic activation of ZOL.ZOL can be metabolized to an α,β-unsaturated imine intermediate by CYP2D6. Pre-treatment of primary hepatocytes with quinidine was able to reverse ZOL-induced cytotoxicity. The finding facilitates the understanding of the mechanisms involved in ZOL-associated liver adverse reactions.

The effects of acute sumatriptan treatment on renal ischemia/reperfusion injury in rat and the possible involvement of nitric oxide

Renal ischemia/reperfusion (I/R) injury is a common pathological condition. Studies reported renal toxicity following administration of triptans, which are commonly used for treating migraine headaches. To investigate the effects of sumatriptan and the molecular mechanisms involved in renal I/R injury in rats, ischemia was induced by bilateral clamping of renal pedicles followed by 24 h of reperfusion. Sumatriptan was administered in three different doses (5, 10, and 20 mg/kg) before I/R injury induction. Biochemical and histopathological changes were evaluated. The contribution of nitric oxide in modulating the effects of sumatriptan was determined by administrating aminoguanidine at 50 mg/kg 60 min before I/R injury. The tissue level of nitrite, superoxide dismutase (SOD), and malondialdehyde (MDA) were measured. Sumatriptan at 10 and 20 mg/kg increased the serum level of creatinine (Cr) and blood urea nitrogen (BUN) significantly. There was also a significant increase in nitrite level of animals that received 10 mg/kg sumatriptan. Co-administration of sumatriptan with aminoguanidine significantly decreased the BUN and Cr. Depletion of SOD level (P < 0.05) and elevation of serum levels of MDA (P < 0.001) indicated the involvement of oxidative stress in sumatriptan adverse effects. Overall, the administration of sumatriptan intensified renal I/R injury through activation of inducible nitric oxide synthase and oxidative responses in rats.

Protective Roles of N-acetyl Cysteine and/or Taurine against Sumatriptan-Induced Hepatotoxicity

Purpose: Triptans are the drug category mostly prescribed for abortive treatment of migraine. Most recent cases of liver toxicity induced by triptans have been described, but the mechanisms of liver toxicity of these medications have not been clear. Methods: In the present study, we obtained LC₅₀ using dose-response curve and investigated cell viability, free radical generation, lipid peroxide production, mitochondrial injury, lysosomal membrane damage and the cellular glutathione level as toxicity markers as well as the beneficial effects of taurine and/or N-acetyl cysteine in the sumatriptan-treated rat parenchymal hepatocytes using accelerated method of cytotoxicity mechanism screening. Results: It was revealed that liver toxicity induced by sumatriptan in in freshly isolated parenchymal hepatocytes is dose-dependent. Sumatriptan caused significant free radical generation followed by lipid peroxide formation, mitochondrial injury as well as lysosomal damage. Moreover, sumatriptan reduced cellular glutathione content. Taurine and N-acetyl cysteine were able to protect hepatocytes against sumatriptan-induced harmful effects. Conclusion: It is concluded that sumatriptan causes oxidative stress in hepatocytes and the decreased hepatocytes glutathione has a key role in the sumatriptan-induced harmful effects. Also, N-acetyl cysteine and/or taurine could be used as treatments in sumatriptan-induced side effects.

Renal cortical infarction following treatment with sumatriptan in a kidney allograft recipient

Renal cortical infarction is a rare cause of acute kidney injury that results from inadequate blood flow to the kidney, most commonly as a consequence of thrombotic or embolic occlusion of the renal artery or profound hypoperfusion. We report the case of a 78-year-old female kidney transplant recipient who developed a migraine headache, took sumatriptan, and soon after developed pain over the allograft and oligoanuric acute kidney injury. Kidney allograft biopsy showed renal cortical infarction. The mechanism of action of sumatriptan involves vasoconstriction, which counters the vasodilatation that is central to the pathogenesis of migraines. This case raises important questions regarding the safety of triptans with calcineurin inhibitors (which also act to vasoconstrict), particularly in elderly patients.

Tachyphylaxis to the sumatriptan-induced contractile effect in the human uterine artery but not in human cerebral blood vessels: pharmacological demonstration of the 5-HT(1B) receptor functionality loss

The in vitro contractile response of the human uterine artery to sumatriptan was compared to that of human cerebral blood vessels. Artery rings were prepared for isometric contraction. Tachyphylaxis to the triptan-induced vascular contraction was observed in the uterine artery, but not in basilar and middle cerebral arteries. To evaluate 5-HT(1) receptor subtypes functionality, concentration-response curves to sumatriptan were performed at 0 and 24 h after uterine artery isolation. Both 10 μmol/l cyanopindolol and 63 nmol/l SB 224,289 (5-HT(1B) receptor antagonists) significantly antagonized the contractile response induced by sumatriptan at 0 h but not after 24 h of uterine artery isolation. The 5-HT(1B/1D) receptor antagonist BRL 15,572 at 10 μmol/l significantly antagonized the sumatriptan contractile response at both experimental conditions. We conclude that the tachyphylaxis to sumatriptan observed in the non-cerebral blood vessels, and not in the cerebral ones, may be due to loss of functionality of the 5-HT(1B) receptor subtype, increasing the safety of triptans.

N-methyl-D-aspartate receptor-mediated modulations of the anti-allodynic effects of 5-HT1B/1D receptor stimulation in a rat model of trigeminal neuropathic pain

Previous studies showed that triptans and other 5-HT(1B/1D)-receptor agonists attenuate hyper-responsiveness to mechanical stimulation of the face in a rat model of trigeminal neuropathic pain, probably by activating 5-HT(1B/1D)-receptors on primary afferent nociceptive fibers. We now tested whether blockade of post-synaptic receptors for the excitatory amino acid glutamate released by these fibers would increase this action. We thus evaluated whether (±)1-hydroxy-3-aminopyrrolidine-2-one (HA-966), an antagonist at the glycine/D-serine site of N-methyl-D-aspartate (NMDA)-receptors, would potentiate the anti-allodynic action of dihydroergotamine and zolmitriptan in rats with chronic constriction injury to the infraorbital nerve (CCI-ION). Complementary studies were performed with other NMDA-receptor ligands and in rats with chronic constriction injury to the sciatic nerve (CCI-SN) for comparison. Injury was produced by loose ligatures of the nerves. Responsiveness to mechanical stimulation (vibrissae or hindpaw territories) with von Frey filaments was used to evaluate allodynia 2 weeks after nerve ligature. Rats received NMDA-receptor ligands or saline 20 min before dihydroergotamine (25-100 μg/kg, i.v.) or zolmitriptan (25-100 μg/kg, s.c.). HA-966 (2.5mg/kg, s.c.), inactive on its own, enhanced the anti-allodynic effects of dihydroergotamine (eightfold increase) and zolmitriptan (threefold increase) in CCI-ION rats, but these drugs exerted no effects in allodynic CCI-SN rats. NMDA-receptor blockade by memantine (5mg/kg, i.p.) also enhanced, whereas activation at glycine/NMDA site by D-cycloserine (3mg/kg, i.p.) reduced the anti-allodynic properties of zolmitriptan in CCI-ION rats. Combined administration of NMDA-receptor antagonist and 5-HT(1B/1D)-receptor agonist may be a promising approach for alleviating trigeminal neuropathic pain.

Migraine and stroke: current perspectives

OBJECTIVE

The purpose of this article is to review the latest concepts regarding migraine and ischemic stroke. In addition, focal neurological deficits and MRI changes in migraine patients will be reviewed.

METHODS

A PubMed search of neurological literature pertaining to this study was conducted using specific keyword search terms pertaining to migraine and ischemic stroke.

RESULTS

Migraine, especially with aura, is a relative risk factor for stroke. Neuroimaging demonstrates the posterior circulation as being most vulnerable, although the reason for this distribution is unclear. Factors that may contribute to stroke in migraine include changes during cortical spreading depression with hyper- or hypoperfusion of neural tissue, vasospasm and endothelial dysfunction. Estrogen affects migraine expression as well as cerebral circulation, yet most women with migraine without aura are not at increased risk. Co-morbidity with patent foramen ovale can be mechanism of both disorders via presumed lack of filtration of microemboli or toxic substances; however, closure with reversal of right to left shunt seems to be more beneficial for cryptogenic stroke than migraine. Migraine and stroke are found in specific genetic disorders such as CADASIL, HERNS and MELAS giving clues to genetic factors. Stroke associated with migraine treatments such as ergots or triptans is rare, and usually associated with special circumstances such as overuse or concomitant thrombogenic conditions.

CONCLUSION

Although true migrainous infarction is rare, our understanding of the subtle associations between migraine and cerebrovascular behavior is expanding.