Cardiovascular Drugs during Pregnancy
“Bert” Bertis Britt Little in Drugs and Pregnancy, 2022
Lidocaine is commonly used as a local anesthetic. This amide is also effective systemically in the treatment of ventricular and supraventricular tachycardia. Amide-type local anesthetics given for paracervical block are associated with spasm of the uterine arteries, causing decreased uterine blood flow. Lidocaine crosses the placenta quickly with fetal levels attaining approximately 50 percent of maternal levels in less than an hour (Rotmensch et al., 1983). Lidocaine’s half-life is two times longer in the fetus/neonate (3 h) than in the mother (1.5–2 h) (Brown et al., 1976). Fetal lidocaine elimination is also prolonged and may persist for up to 48 hours after birth (Garite and Briggs, 1987). IMPORTANT NOTE: most information available regarding pharmacokinetics of lidocaine in pregnant and postpartum women and newborns is from studies of regional or local anesthesia (Rotmensch et al., 1983). No published data are available on lidocaine from women who received the drug for cardiac arrhythmias. However, local anesthetics may be given in toxic doses and may result in central nervous system and cardiac side effects in both the mother and the fetus. Lidocaine is apparently not associated with birth defects at acute therapeutic levels in humans or in chronic doses in animals (Fujinaga and Mazze, 1986; Heinonen et al., 1977; Rotmensch et al., 1983), but timing, duration(s), and dose levels of exposure are not known. Potential for lidocaine toxicity risk is minimized when maternal lidocaine levels are maintained at less than 4 mg/mL (Bhagwat and Engel, 1995).
Tendinopathy
Kohlstadt Ingrid, Cintron Kenneth in Metabolic Therapies in Orthopedics, Second Edition, 2018
Topical nonsteroidal anti-inflammatory drug (NSAID) creams or gels have limited efficacy since t endinopathy is not an inflammatory condition. There may be a role for topical lidocaine as an agent to provide some pain relief. Clinically, it appears that pain processing and sensitization can improve if the patient has a localized prolonged numbing effect. Nitric oxide may play a role in collagen and protein synthesis repair in tendinopathy. Glyceryl trinitrate has been studied in supraspinatus tendinopathy and has shown efficacy in reducing pain and improving function (Assem 2015) where its benefit is theorized to be increasing regional blood flow. Doses ranged from 1.25 mg to 5 mg/24 hours. Topical glyceryl trinitrate treatment decreased pain scores, improved range of motion and improved muscular force. The study followed patients for up to 6 months (Paoloni, Appleyard, Nelson & Murrell, 2005). It should be used with caution in any patient that has low blood pressure and also noted that headache is a frequent side effect. Transderm nitro patches should not be used as an isolated treatment but could be added to a patient’s treatment regimen to decrease pain and improve function in tendinopathy. The studies are varied in terms of duration and length of dosage. It would be reasonable to try a patch at 8–12 hours per day and use it for at least six weeks.
Pharmacology of local anesthetics
Pamela E. Macintyre, Stephan A. Schug in Acute Pain Management, 2014
Lidocaine (lignocaine) is the most widely used short-acting local anesthetic worldwide. Absorption can be reduced, and therefore length of action increased and the risk of toxicity decreased, by the addition of vasoconstrictors to the solution. Although often used to establish regional and local anesthetic blocks for operative procedures, it is not commonly used in the ongoing management of acute pain. The reasons for this include the development of acute tolerance and tachyphylaxis as well as the propensity to cause a greater degree of motor block for a given degree of sensory block than the long-acting local anesthetics (Mogensen, 1995). Lidocaine is available in a number of preparations: ointments, jelly, topical solutions including a spray, and formulations for injection. It has also been administered by nebulizer to obtain topical anesthesia of the upper airway and intravenously for the treatment of cardiac arrhythmias, neuropathic pain, and to improve postoperative recovery of gastrointestinal function (Borgeat and Aguirre, 2010) (see Chapter 12). A mixture of lidocaine and prilocaine (2.5% of each), called EMLA™ cream (eutectic mixture of local anesthetics), can be used as a topical local anesthetic agent for skin (ANZCA and FPM, 2010). Applied under an occlusive dressing or as a patch, it takes 30–60 minutes to have its full effect. It has been used prior to the insertion of intravenous cannulae or other needles (especially in children) and for local procedures such as superficial skin surgery and skin grafting. A topical lidocaine patch is also available in some countries and is recommended as first-line treatment of localized neuropathic pain (e.g., postherpetic neuralgia) (ANZCA and FPM, 2010).
Mucosal co-delivery of ketorolac and lidocaine using polymeric wafers for dental application
Published in Drug Delivery, 2018
Gina S. El-Feky, Rania Farouk Abdulmaguid, Gamal M. Zayed, Rabab Kamel
The current study aimed to investigate the effectiveness of a developed sodium alginate and polyvinylpyrrolidone K-25 (PVP K-25) polymeric wafer for the co-delivery of ketorolac and lidocaine to soft tissues for healing and pain control following gingivectomy. Nine ketorolac/lidocaine lyophilized wafers were formulated and assessed for their hydration capacity, mucoadhesion ability and in vitro release profile to select the optimum system for further clinical investigation. Wafer F6 containing 2:1 sodium alginate to PVP K-25 and 10% glycerol showed optimum properties and was selected for the clinical study. Twenty patients were included in the study and the ketorolac/lidocaine wafer was assessed versus a market product. Visual pain analog was evaluated daily for the first week and wound healing index was evaluated for one week, two weeks and one month following the procedure. The developed ketorolac/lidocaine polymeric wafer proved to be an effective method of reducing pain and discomfort together with enhancing wound healing following gingivectomy.
Does adjusting the pH of lidocaine reduce pain during injection?
Published in Journal of Plastic Surgery and Hand Surgery, 2015
Trine I Skarsvåg, Kathrine J Wågø, Lena F Tangen, Janne S Lundbom, Tonje Hjelseng, Solveig Ballo, Vilhjalmur Finsen
Background: Receiving local anaestethic injection is painful. A double-blinded randomised study with 32 healthy adult volunteers was performed, with the aim of investigating the effect of buffering lidocaine to reduce the pain during injection. Methods: Each participant received two subcutaneous injections of 4.5 ml lidocaine 1% on the lower left and right quadrants of the abdomen. One solution was plain lidocaine (pH 6.55) and the other was lidocaine buffered with sodium bicarbonate in a ratio of 9:1 (pH 7.30). After each injection the participant marked the pain experienced during the injection on a visual analogue scale (VAS; 0 = best, 100 = worst), in addition to verbally stating which injection they found was the least painful. Results: A total of 20 stated that they preferred the buffered solution, while eight said that they preferred the unbuffered solution (p < 0.002). The mean VAS pain-score was 15 (SD = 12) for the buffered injections and 20 (SD = 12) for the unbuffered injections (p < 0.017). Conclusion: The conclusion is that the pain experienced during the injection of lidocaine can be significantly reduced by buffering the solution before injection.
Utility of lidocaine as a topical analgesic and improvements in patch delivery systems
Published in Postgraduate Medicine, 2020
Interest in and use of topical analgesics has been increasing, presumably due to their potential utility for relief of acute and chronic pain. Topically applied agents with analgesic properties can target peripheral nociceptive pathways while minimizing absorption into the plasma that leads to potential systemic adverse effects. Clinical trials have found 5% lidocaine patches to be effective and well tolerated for the treatment of post-herpetic neuralgia (PHN) with a minimal risk of toxicity or drug–drug interactions. With this patch formulation, the penetration of lidocaine into the skin produces an analgesic effect without producing a complete sensory block. Use of topical lidocaine is supported by clinical practice guidelines, including first-line treatment by the American Academy of Neurology (guidelines retired 2018), the European Federation of Neurological Societies and second-line by the Canadian Pain Society. FDA approved 5% lidocaine patches in 1999, and a 1.8% topical lidocaine system in 2018 – both indicated for the treatment of pain secondary to PHN. The 1.8% system offers a more efficient delivery of lidocaine that is bioequivalent to 5% lidocaine patches, but with a 19-fold decrease in drug load (i.e., 36 mg versus 700 mg) as well as superior adhesion that allows the patch to maintain contact with the skin during the 12-h administration period. Although topical lidocaine formulations have advanced over time and play an important role in the treatment of PHN, a variety of other conditions that respond to topical lidocaine have been reported in the literature including PHN, lower back pain, carpal tunnel syndrome, diabetic peripheral neuropathy, and osteoarthritis joint pain. Other neuropathic or nociceptive pain syndromes may respond to topical lidocaine in select cases and warrant further study. Clinicians should consider local anesthetics and other topical agents as part of their multimodal treatments of acute and chronic pain.
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