Effects of verapamil on spinal anesthesia with local anesthetics

Effect of Verapamil as an Adjuvant to Levobupivacaine in Supraclavicular Brachial Plexus Block

BACKGROUND

Many adjuvants have been used with local anesthetics to reduce the time of onset and prolong the duration of analgesia in brachial plexus blocks. However, few studies are there using verapamil as an adjuvant with levobupivacaine.

AIMS

This study aims to study the effects of verapamil as adjuvant to levobupivacaine in supraclavicular block for upper extremity surgery.

METHODS

In this double-blinded clinical trial, 60 American Society of Anesthesiologist Class I and II patients posted to undergo upper extremity surgery were divided into 2 different groups randomly. In Group A, the patients received 30 ml levobupivacaine 0.5% plus 2 ml normal saline and Group B patients received 30 ml levobupivacaine 0.5% plus 5 mg verapamil diluted to 2 ml normal saline for supraclavicular block. Time of request for rescue analgesia, onset and duration of sensory motor blocks and changes in hemodynamic parameters were studied and analyzed. P < 0.001 was considered statistically significant.

RESULTS

Time for a request for rescue analgesia was 425.80 ± 90.46 min in Group B and 366.13 ± 70.42 min in Group A which was clinically significant. The mean of sensory and motor block onset time in Group B was less than in Group A, the difference between the two groups being statistically significant (P < 0.001). In Group A, mean duration of sensory block was 316.13 ± 91.08 min and in Group B was 375.83 ± 114.48 min, which was statistically significant (P < 0.001).

CONCLUSION

The addition of verapamil as an adjuvant to levobupivacaine in brachial plexus blockade delayed the requirement of rescue analgesia with decreased onset time and prolonged duration of sensory and motor block characteristics.

Efficacy of diltiazem as an adjunct to lignocaine in intravenous regional anesthesia

Background:

Various adjuncts have been used with lignocaine to decrease tourniquet pain and prolong post-operative analgesia during intravenous regional anesthesia (IVRA). Calcium-channel blockers potentiate the analgesic effect of local anesthetics. This study was designed to evaluate the efficacy of diltiazem as an adjunct to lignocaine in IVRA with respect to tourniquet tolerance, perioperative analgesia, and quality of anesthesia.

Methods:

In this prospective, randomized, and double-blind study, 40 patients (American Society for Anesthesiologists grade I/II) undergoing elective hand surgery under IVRA were assigned into two groups of 20 each and administered IVRA either with lignocaine 3 mg/kg (group Lignocaine (L)) or lignocaine 3 mg/kg plus diltiazem 0.2 mg/kg (group Lignocaine-Diltiazem (LD)) with normal saline (total volume-40 ml). Hemodynamic parameters, onset of the complete sensory blockade, motor blockade, and intraoperative (tourniquet pain) and post-operative Visual Analogue Scale scores, total intraoperative and consumption of post-operative fentanyl intraoperative were recorded.

Results:

Sensory block was established in 2.5±0.688 min in group LD verses 5.60±0.851 min in group L. Motor blockade was established in 8.65±0.933 min in group LD and 13.46±0.604 min in group L. The mean VAS scores >3 were attained early at 30 min (3.1±0.912) in group L. Patients in group L requested early rescue analgesic at 30±8.633 min compared with 49.64±7.958 min in group LD.

Conclusions:

Diltiazem as an adjunct to lignocaine provided enhanced intraoperative and post-operative analgesia without any significant side effects.

Verapamil as an Adjunct to Local Anaesthetic for Brachial Plexus Blocks

BACKGROUND

Calcium channel blockers potentiate the effects of local anaesthetics. We examined the effect of adding verapamil to local anaesthetic solution on anaesthetic duration in patients undergoing surgery under brachial plexus block.

METHODS

This study was a prospective, randomized, controlled, double blind study. Sixty patients undergoing elective upper limb surgery were divided into two groups of 30 each. Group A received 40 ml of 1% lignocaine with 0.25% bupivacaine, while Group B patients had 2.5 mg verapamil added.

RESULT

Onset of sensory blockade time was marginally faster in Group B (23.2 ± 3.94 minutes) as compared to Group A (23.9 ± 4.13 minutes). However this difference was statistically not significant. The increase in duration of sensory blockade in Group B (185 ± 46.52 minutes) as compared to Group A (157 ± 44.28 minutes) was statistically significant (p= 0.011). Increase in duration of motor blockade in Group B (161 ± 46.14 minutes) as compared to Group A (149 ± 42,76 minutes) was statistically not significant (p = 0.15). Similarly prolongation of analgesic duration in Group B (318 ± 69.54minutes) as compared to Group A (302 ± 0.69 minutes) was statistically not significant (p=0.18).

CONCLUSION

We conclude that adding verapamil to brachial plexus block can prolong sensory anaesthesia without any effect on analgesic duration.

Potential role of female sex hormones in the pathophysiology of migraine

Clinical evidence indicates that female sex steroids may contribute to the high prevalence of migraine in women, as well as changes in the frequency or severity of migraine attacks that are in tandem with various reproductive milestones in women's life. While female sex steroids do not seem to be involved in the pathogenesis of migraine per se, they may modulate several mediators and/or receptor systems via both genomic and non-genomic mechanisms; these actions may be perpetuated at the central nervous system, as well as at the peripheral (neuro)vascular level. For example, female sex steroids have been shown to enhance: (i) neuronal excitability by elevating Ca(2+) and decreasing Mg(2+) concentrations, an action that may occur with other mechanisms triggering migraine; (ii) the synthesis and release of nitric oxide (NO) and neuropeptides, such as calcitonin gene-related peptide CGRP, a mechanism that reinforces vasodilatation and activates trigeminal sensory afferents with a subsequent stimulation of pain centres; and (iii) the function of receptors mediating vasodilatation, while the responses of receptors inducing vasoconstriction are attenuated. The serotonergic, adrenergic and gamma-aminobutyric acid (GABA)-ergic systems are also modulated by sex steroids, albeit to a varying degree and with potentially contrasting effects on migraine outcome. Taken together, female sex steroids seem to be involved in an array of components implicated in migraine pathogenesis. Future studies will further delineate the extent and the clinical relevance of each of these mechanisms, and will thus expand the knowledge on the femininity of migraine.

New and future migraine therapy

Modern neuroscience advanced our understanding of putative migraine mechanisms, which led to improved therapeutics. Indeed, mechanism-based acute migraine therapy gained steam in the early 1990s after the introduction of the triptans (5-HT1B,D agonists). Post-triptans, novel targets such as calcitonin gene-related peptide (CGRP) antagonists, inhibitors of excitatory glutamatergic receptors, and nitric oxide synthase (NOS) inhibitors are leading the pack in this exploding field of discovery research. In contrast, novel therapeutic targets for migraine prevention are lacking despite a hugely unmet need. To date, migraine prophylactic drugs are advanced based on expanded indications for already approved pharmaceuticals (e.g., topiramate, valproate, propranolol, and timolol). An improved understanding of the predisposition to an attack, genomic discoveries, valid and reliable biomarkers and surrogates, and predictive preclinical models likely will unravel the neuronal substrates for central hyperexcitability and nociceptive dysmodulation, hopefully leading us to better mechanism-based targets for prevention, and ultimately yielding drugs with optimal therapeutic ratios or indices.