Gabapentin "add-on therapy" for idiopathic chronic hiccup (ICH)

Detailed Kinetic and Mechanistic Study for the Preparation of Silver Nanoparticles by a Chemical Reduction Method in the Presence of a Neuroleptic Agent (Gabapentin) at an Alkaline pH and its Characterization

For the very first time, a detailed kinetic study for the preparation of silver nanoparticles (silver NPs) by neuroleptic agent gabapentin (GBP) in the absence of a stabilizer has been reported in this investigation. This paper is devoted to the preparation of silver nanoparticles by a chemical reduction method in which gabapentin acts as both a reductant and a stabilizer, and AgNO₃ is used as a source of Ag⁺ ions and NaOH for maintaining the alkaline medium. A UV-visible spectrophotometer is used to monitor the progress of the reaction kinetics in an aqueous medium by changing the concentration of different variables such as AgNO₃, NaOH, and gabapentin at 40 °C. It is found that the reaction rate follows a pseudo-first-order reaction. The thermodynamic activation parameters were also studied at five different temperatures (303, 308, 313, 318, and 323 K) and used in the support of the proposed mechanistic scheme for the formation of silver nanoparticles. The prepared silver nanoparticles were characterized using different techniques: UV-visible spectrophotometry, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, and powder X-ray diffraction. The average particle size was observed in the range of 5-45 nm.

Chronic Hiccups

PURPOSE OF REVIEW

Nearly 4000 patients will be admitted to hospital in the US this year for hiccups. Hiccups are controlled by a complex reflex arc between peripheral receptors and the brainstem. Any disruption along this pathway may produce hiccups. Typically, hiccups resolve spontaneously but in certain pathologies symptoms may persist. Persistent hiccups may be considered a sign of underlying pathology. The most common cause involves GERD.

RECENT FINDINGS

Based on etiologies, studies have shown that first-line therapy should use a proton pump inhibitor (PPI) and involve appropriate gastrointestinal consultation. If symptoms persist, other etiologies such as central causes need to be explored.

SUMMARY

We review the pathophysiology of hiccups including multiple causes and the appropriate work up for each. We review several studies examining new treatments, both pharmacological and interventional, that may help patients. Initial therapy should still involve a PPI but several new therapies may be beneficial.

Neurotransmitters in hiccups

Hiccups are the sudden involuntary contractions of the diaphragm and intercostal muscles. They are generally benign and self-limited, however, in some cases they are chronic and debilitating. There are approximately 4000 admissions for hiccups each year in the United States. The hiccup reflex arc is composed of three components: (1) an afferent limb including the phrenic, vagus, and sympathetic nerves, (2) the central processing unit in the midbrain, and (3) the efferent limb carrying motor fibers to the diaphragm and intercostal muscles. Hiccups may be idiopathic, organic, psychogenic, or medication-induced. Data obtained largely from case studies of hiccups either induced by or treated with medications have led to hypotheses on the neurotransmitters involved. The central neurotransmitters implicated in hiccups include GABA, dopamine, and serotonin, while the peripheral neurotransmitters are epinephrine, norepinephrine, acetylcholine, and histamine. Further studies are needed to characterize the nature of neurotransmitters at each anatomical level of the reflex arc to better target hiccups pharmacologically.

Transient hiccups associated with oral dexamethasone

Hiccups, or singulata (hiccup is singultus), are commonly experienced by most people at one time or another and are usually brief and self-limiting. Although pharmacotherapeutic agents are not generally considered causal in the etiology of hiccups, many clinicians empirically associate episodic hiccups in their patients as being drug induced. The two classes of drugs most often cited as causing hiccups are corticosteroids and benzodiazepines. This report involved a patient who was given preoperative dexamethasone and developed hiccups before anesthesia and surgery commenced. He at no time was in distress, and the surgical procedure was completed without complication. By the second postsurgical day his hiccups were resolved completely. Although the association may be anecdotal, many clinicians consider hiccups a potential side effect of steroid therapy, especially high doses of steroids. Of interest in this case is the relatively low dose of corticosteroid used, albeit apparently linked to his hiccups. Practitioners should be aware of this potential condition.

Gabapentin Therapy of Hiccups

OBJECTIVE:

To determine whether gabapentin is effective in the treatment of persistent or intractable hiccups.

DATA SOURCES:

A search of MEDLINE (1966-March 2013) using the MeSH search terms gabapentin, hiccups, and hiccups/drug therapy was performed. Additional databases searched included Web of Science (1945-March 2013) and International Pharmaceutical Abstracts (1970-March 2013) using the text words gabapentin and hiccups. Bibliographies of relevant articles were reviewed for additional citations.

STUDY SELECTION AND DATA EXTRACTION:

All data sources were considered for inclusion. Preference was given for articles written in English, although one abstract in German was used.

DATA SYNTHESIS:

Because of the low incidence of persistent or intractable hiccups, few if any controlled clinical trials are conducted on the efficacy of drug treatment. Therefore, most of the data involve case reports or case series. We evaluated 17 case reports and 2 case series involving gabapentin therapy for persistent or intractable hiccups. Therapeutic outcomes with gabapentin were positive in all cases, with temporal evidence suggesting an effect, but outcomes often were obscured by combination therapy and comorbidities in some cases. Case reports suggest that gabapentin might be useful as a second-line agent in patients undergoing stroke rehabilitation or in the palliative care setting where chlorpromazine adverse effects are undesirable. Gabapentin was very well tolerated, with only a few minor adverse effects.

CONCLUSIONS:

Gabapentin has a similar body of evidence as other pharmacotherapeutic agents used to treat hiccups. Gabapentin is well tolerated and should be considered as a second-line agent in selected patients.

Gabapentin for Intractable Hiccups in Palliative Care

Intractable hiccups are not common in the general population or in the palliative care population but can adversely impact quality of life and cause other complications such as weight loss and sleep disturbance. Many treatments have been proposed for intractable hiccups, but there is little consensus regarding treatment in the medical literature. This is partly because hiccups are relatively uncommon and many of the proposed treatments are unproven or have long-term side effects. Pharmacologic treatments rather than home remedies or surgical treatments are more appropriate for the palliative care patient. Gabapentin is a promising medication for the treatment of intractable hiccups for its safety, lack of serious side effects, and rapid onset of action. Further research is indicated to determine whether gabapentin is consistently effective.

Alpha-2-delta ligands for singultus (hiccup) treatment: three case reports

Chronic idiopathic singultus (hiccup) is a debilitating condition affecting mostly elderly males. While in the past, pharmacologic singultus treatment was mostly "trial and error," more recently, treatment has become both more evidence based and pathophysiology guided. A combination of an acidity-reducing drug (H(2)-receptor blocker or proton pump inhibitor) with baclofen (gamma-amino-butyric-acid receptor type B agonist) has become the most widely used regimen. Some clinicians replace or supplement baclofen with gabapentin. We present three cases of chronic idiopathic hiccup managed with gabapentin or another alpha-2-delta ligand, pregabalin. This is the first reported use of pregabalin for this indication.

Refractory Hiccup

OBJECTIVE

To report a patient with intractable hiccup which improved with gabapentin.

CASE REPORT

A 69-year-old woman diagnosed with refractory hiccup that started 50 years before improved dramatically after a trial of gabapentin for essential tremor. Gabapentin withdrawal led to reappearance of hiccup, which improved again after its reintroduction.

CONCLUSIONS

Gabapentin should be considered as a possible therapy for refractory hiccup.

Vagus nerve stimulation for chronic intractable hiccups

✓ Intractable hiccups are debilitating and usually a result of some underlying disease. Initial management includes vagal maneuvers and pharmacotherapy. When hiccups persist despite medical therapy, surgical intervention rarely is pursued. Cases described in the literature cite successful phrenic nerve blockade, crush injury, or percutaneous phrenic nerve pacing. The authors report on a case of intractable hiccups occurring after a posterior fossa stroke. Complete resolution of the spasms has been achieved to date following the placement of a vagus nerve stimulator.

Management of hiccups in the palliative care population

There are close to a hundred causes for hiccups, or singultus, the most common of which are gastrointestinal. Causes may be natural or drug induced, and the same agents that are used to treat hiccups may also induce them. Hiccups can be classified by their duration, as follows: up to 48 hours, acute; longer than 48 hours, persistent; and more than two months, intractable. Treatment options for hiccups can include both pharmacologic and nonpharmacologic agents. If the cause of hiccups can be identified, it is, of course, preferable to direct the treatment at that cause. However many times a cause cannot be identified; in this case, general measures or treatments should be instituted. Intractable hiccups can occur in the palliative care population. When they do, it can be extremely distressing and have a significant impact on quality of life. Pharmacologic approaches are often the most rational therapies for these patients. Baclofen seems to be a promising drug for use with both palliative care and perioperative patients, and using garabentin as an add-on to baclofen may also be a reasonable option to consider

Anesthesia as therapy for persistent hiccups

IMPLICATIONS

Chronic hiccups may be a serious therapeutic problem. Pharmacological treatment with increasing dosages of baclofen, carbamazepine, or gabapentin is not always successful. In this paper, the use of general anesthesia with positive-pressure ventilation and muscle relaxation for the termination of chronic hiccups is described.