Tuesday, December 20, 2016

Intramuscular Injections and Lignocaine


Availability
  • Lignocaine HCL 2% (no preservative) (100mg/5ml)
  • Lignocaine HCL 2% (preservative) (200mg/10ml)
Rationale
  • One of the major disadvantages of IM injection of penicillins, such as benzathine penicillin G, is pain at the injection site.
  • Farhadi et al. reported that the average pain intensity in patients receiving IM injection of benzathine penicillin was described as "severe" with a mean visual analog scale (VAS) score of 7.4/10
  • Injection pain can be greatly reduced by administering drugs in combination with local anesthetics like lidocaine.
  • Lidocaine is a sodium-channel-blocking drug and an extremely versatile local anesthetic agent which has remained a widely used agent due to its potency, rapid onset and intermediate duration of action
Stability
  • A few studies have examined the influences of lidocaine as a diluent on pharmacokinetics of IM penicillins or cephalosporins in human and none showed any changes in pharmacokinetic parameters of these antibiotics when mixed with lidocaine
  • Patel et al. investigated the effect of lidocaine 1% as a diluent on the pharmacokinetics and tolerance of IM ceftriaxone and showed that lidocaine neither changed parameters nor altered its bioavailability
  • Amir et al. compared concentration and injection pain of benzathine penicillin G between two diluents, either sterile water or lidocaine hydrochloride 1%. They found that although lidocaine significantly reduced injection pain, it did not change penicillin concentration in body fluids
Toxicity
  • Despite potential toxicity of lidocaine, its usual dose for IM penicillin injections is 10-60 mg (1-3 mL of lidocaine 1% or 2%) which is significantly less than the recommended maximum dose for local anesthetics without epinephrine (4.5 mg/kg)
Administration Recommendations

Vol of Lignocaine 2%
Diluent Solutions
Used to Reconstitute:
1.
1.75 ml
1.75 ml of
NS, 1/2NS, D5, NSD5
1g Ceftriaxone powder
2.
0.25ml
WFI

1.2 MU Benzathine Penicillin powder
in at least 3ml of WFI
0.6 MU (2 ml)
2.4MU (5 ml) 
References:
  1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3464756/
  2. Product Leaflets
  3. https://www.health.govt.nz/.../nursing_guidance_-_administering_im_penicillin.pdf

No comments:

Post a Comment

Note: Only a member of this blog may post a comment.