Lidocaine in fibromyalgia: A systematic review

Table 1 Clinical and demographic characteristics of the xx studies on fibromyalgia and lidocaine treatment

Ref.	Study design	N, female sex	Age, yr	Disease duration	Follow-up	Lidocaine prescription	Concomitant treatment	Short-term VAS,		Long-term VAS		Other outcomes	Adverse effects
								Pre and post lidocaine	Pre and post, placebo	Pre and post lidocaine	Pre and post placebo
Verd et al[5]	Prospective	48, 95.8%	Median age-55		90 d	Escalating dose from 2 mg/kg to 5 mg/kg per day, IV during 10 d	-	Pain measured by BPI 29.5→26.5	-	In 90 d BPI = 30.0	-	Improved in MOS and EXPEC; Short-lived improvement in BPI, BFI and depression	Nausea (n = 8); Worsening pain (n = 1)
Wilderman et al[6]	Retrospective	74, 9.7%	51.3	NA	5 mg/kg→65.7 d; 7.5 mg/kg→86.3 d; 7.5 mg/kg→90.9 d	Escalating doses: 5 mg/kg, 7.5 mg/kg and 7.5 mg/kg + magnesium 2.5 g IV	None	∆ VAS in 5 mg/kg = 2.41; ∆ VAS in 7.5 mg/kg = 3.15; ∆ VAS in 7.5 mg/kg + Mg = 3.62	NA	Pain relief:In 30.2% of 5 mg/kg- median time 62 d; In 39.1% in 7.5 mg/kg; median time 62.5 d; 40.6% in 7.5 mg/kg + Mg; Median time 64 d	NA	-	24/222 infusions (10.8%)-dizziness, nausea, hyperglycemia, headache, lip numbness and mild dyspnea
Kim et al[7]	Retrospective	55, 94.5%	NA	NA	After 1 infusion	5 mg/kg (maximum of 500 mg), IV		7.6 ± 1.6→5.8 ± 2.2	-	-	-	Caucasians and non-smokers had better results	NA
Albertoni Giraldes et al[8]	RCT	42, 95%	42.4 ± 9.4	6.0 ± 5.05	8 wk	250 mg/wk – for 4 wk IV; vs saline	Amitriptyline 25 mg, paracetamol if needed.	6 ± 1.3 3.9 ± 2.8	7.2 ± 1.3→2.7 ± 2.9	-	-	IL-1, IL-6 and IL-8 values did not change	Placebo equal to lidocaine: nausea, vomiting, drowsiness, paresthesia, constipation and dry mouth
Staud et al[9]	Prospective	62, 100%	45.8 ± 14.8	NA	Data collection just after injections	Group 1 (n = 20)- 4 injections of 50 mg lidocaine, IM; Group 2 (n = 21)- 2 injections 50 mg lidocaine + 2 saline, IM; Group 3 (n = 21)- four injections saline, IM	Muscle relaxing drugs and/or tricyclics were allowed	VAS declined 38%	-	-	-	Mechanical and heat hyperalgesia decreased significantly	NA
Vlainich et al[10]	RCT,	30, 100%	Group 1-40.9 ± 11.6; Group 2-44.7 ± 10.5	NA	4 wk	Group 1- (n = 15) lidocaine 240 mg/wk for 4 wk, IV; Group 2- (n = 15) Saline	Amitriptyline 25 mg	7.6 ± 0.8→4.1 ± 2.3	7.0 ± 1.2→4.0 ± 2.1	-	-	norepinephrine and serotonin levels unchanged dopamine levels ↑ week 4 in the placebo group.	No
Schafranski et al[11]	Prospective	23, 95.6%	NA	NA	4 wk	Sequential lidocaine infusions from 2-5 mg/kg for 5 d, IV	None	8.1 ± 1.7→6.8 ± 2.4	-	Mean VAS of pain = 7.1 ± 2.3 in 30 d	-	FIQ, HAQ improved significantly	No
Raphael et al[12]	Prospective and retrospective	106, 92% prospective arm (to see side effects); 50, 82%retrospective arm (to see efficacy)	51.4 prospective arm; 50.2 retrospective arm	Prospective arm- NA; 6.6 ± 4.5 yr in retrospective arm	N/A	Started at 5 mg/kg-100 mg and increased to 5 mg/kg+150 mg (maximum 550 mg) IV; For 6 consecutive days	None	Only in the retrospective arm 9→5; Mean duration pain relief 11.5 ± 6.5 wk	-		-	No improvement in work status; improvement in several sociological and psychological dimensions	Only in the prospective arm; 2 major effects: (pulmonary edema and supra ventricular tachycardia); 42/106 minor effects: Hypotension (n = 17); Headache (n = 8), hypertension (n = 5), tachycardia (n = 1), arrhythmia (n = 1), pulmonary edema (n = 1)
Bennett et al[13]	Prospective	10, 100%	44.2	16 (1-192) mo	4 wk	Started at 250 mg/d and increased by 50 mg/d to 500 mg/dfor 6 d, IV	Haloperidol 0.5 mg/d + clomipramine 10 mg/d or Amitriptyline 10 mg/d	8 4.1	-	Mean VAS of pain = 5.4 in 30 d	-	Stopped analgesics. Mood improved but not statistically significant	None
Sörensen et al[14]	Double blind, placebo-controlled	11, 100%	41, (range 21-59)	5 yr (range 2-11)	1 wk after 2nd injection	2 injections, IV; 5 mg/kg vs saline	Paracetamol or dextropropoxyphene	(VAS from 0-100); 6.1→4.5	(VAS from 0-100); 51→51	-	-	Tender points, muscle endurance and muscle strength (except dorsiflexors of wrist) unchanged	NA

VAS: Visual analogue scale from 0-10 except Sörensen et al[14], which was 0-100; ∆ VAS: Difference in VAS pre and post infusions; IV: Intravenous; IM: Intra muscular; NA: Not available; RCT: Randomized controlled trial; IL: Interleukin, MOS: Medical outcome sleep scale; EXPEC: Patient’S expectations; BPI: Brief pain inventory; BFI: Big five inventory.