Pregabalin-induced urticarial rash and neutropenia in a renal transplant recipient: a case report

The synergistic anti-nociceptive effects of nefopam and gabapentinoids in inflammatory, osteoarthritis, and neuropathic pain mouse models

Pain is a common public health problem and remains as an unmet medical need. Currently available analgesics usually have limited efficacy or are accompanied by many adverse side effects. To achieve satisfactory pain relief by multimodal analgesia, new combinations of nefopam and gabapentinoids (pregabalin/gabapentin) were designed and assessed in inflammatory, osteoarthritis and neuropathic pain. Isobolographic analysis was performed to analyze the interactions between nefopam and gabapentinoids in carrageenan-induced inflammatory pain, mono-iodoacetate-induced osteoarthritis pain and paclitaxel-induced peripheral neuropathic pain in mice. The anti-inflammatory effect and motor performance of monotherapy or their combinations were evaluated in the carrageenan-induced inflammatory responses and rotarod test, respectively. Nefopam (1, 3, 5, 10, 30 mg/kg, p.o.), pregabalin (3, 6, 12, 24 mg/kg, p.o.) or gabapentin (25, 50, 75, 100 mg/kg, p.o.) dose-dependently reversed mechanical allodynia in three pain models. Isobolographic analysis indicated that the combinations of nefopam and gabapentinoids exerted synergistic anti-nociceptive effects in inflammatory, osteoarthritis, and neuropathic pain mouse models, as evidenced by the experimental ED50 (median effective dose) falling below the predicted additive line. Moreover, the combination of nefopam-pregabalin/gabapentin alleviated carrageenan-induced inflammation and edema, and also prevented gabapentinoids-related sedation or ataxia by lowering their effective doses. Collectively, the co-administration of nefopam and gabapentinoids showed synergistic analgesic effects and may result in improved therapeutic benefits for treating pain.

Pregabalin-induced delayed cutaneous hypersensitivity reaction occurring after 40 days of use: a case report

Pregabalin is the first-line treatment for neuropathic pain. Cases of cutaneous hypersensitivity reactions caused by pregabalin generally occur within 2 weeks of initiating medication. We report a rare case of a delayed cutaneous hypersensitivity reaction caused by pregabalin, which was confirmed by a drug provocation test. A 72-year-old man with severe herpes zoster neuralgia developed maculopapular drug eruption covering 80% to 90% of his total body surface area after 40 days of combined multidrug analgesia. A drug provocation test for pregabalin was positive. The time interval between initiating medication and the onset of the patient's rash was the longest and he also had the largest area of skin affected compared with patients with a similar condition in previous related reports. Remaining vigilant for possible adverse cutaneous hypersensitivity reactions during treatment is important because of the long-term course of pregabalin treatment for neuropathic pain.

Pregabalin Induced Maculopapular Eruption in an Elderly Male

Pregabalin is used in the treatment of neuropathic pain of various etiologies and as adjuvant in epilepsy. Blockade of the α2δ subunit of L and N type Ca-channels is its main mechanism of neurotropic action. Compared to other antiepileptics like phenytoin, valproate and lamotrigine, and other neuropathic pain medications such as amitriptyline and duloxetine, pregabalin has a relatively favorable safety profile and hence is a drug of choice for many geriatricians. Here we describe a case of maculopapular rash induced by pregabalin in an elderly man which resolved with withdrawal of the offending drug and conservative management. We have also conducted a literature review of similar cases and highlight the clinical patterns and management strategies for pregabalin induced skin rashes.

A Probable Case of Mirogabalin-Induced Neutropenia

Mirogabalin is a novel ligand for the α2δ subunit of voltage-gated calcium channels and is used to treat neuropathic pain in a similar manner to pregabalin. Although the frequency of pregabalin-induced neutropenia has been reported as 0.3%-1%, mirogabalin-induced neutropenia has not previously been reported in the literature. Herein, we report what we believe is the first case of neutropenia induced by mirogabalin. A 77-year-old woman with squamous cell carcinoma of the lung had been taking mirogabalin at 10 mg/day for six weeks prior to admission to our hospital. She had received two courses of chemotherapy with carboplatin and nanoparticle albumin-bound (nab)-paclitaxel for lung cancer until four months before admission, followed by two courses of nivolumab until one month before admission. The patient was hospitalized for urinary tract infection (UTI), which improved with oral amoxicillin/clavulanic acid at 500/125 mg three times daily for five days (until the fifth hospital day). After that, she underwent rehabilitation to improve muscle strength. During rehabilitation, neutropenia (1,278/µL) was noted, acetaminophen and mexiletine were ceased, and filgrastim was started on hospital day 17. The neutrophil count was 755/µL on hospital day 18. Mirogabalin was discontinued on hospital day 19. The neutrophil count fell to 320/µL and 118/µL on hospital day 20 and day 21, respectively, and recovered to 1,064/µL on hospital day 24. Acetaminophen and mexiletine were resumed on hospital day 31 and neutropenia has not recurred since.