How many times have you given your patient IM ceftriaxone for that presumed gonococcal infection? ... still counting?
Many of us learned (or at least thought we learned) that ceftriaxone has to be administered IM to get the ‘depot’ effect.
Myth busted: There is no depot effect. IV and IM ceftriaxone have very similar pharmacokinetic profiles. Let me prove it to you, straight from the FDA-approved ceftriaxone package insert.
Time after dose administration (hrs) and Average plasma concentration (mcg/mL)
| Dose/route | 0.5 hr | 1 hr | 2 hr | 4 hr | 6 hr | 8 hr | 12 hr | 16 hr | 24 hr |
| 0.5 g IV | 82 | 59 | 48 | 37 | 29 | 23 | 15 | 10 | 5 |
| 0.5 g IM | 22 | 33 | 38 | 35 | 30 | 26 | 16 | unknown | 5 |
- The plasma concentrations are almost identical after IM and IV administration through 24 hours.
- The volume of distribution is the same for both parenteral routes, too. This means that its penetration into the “affected area” is similar.
- For further proof, the CDC Guidelines recommend IV or IM ceftriaxone interchangeably for most gonococcal infections in infants and children.
Trick of the Trade:
If the patient already has an IV line, give IV ceftriaxone instead of IM .
While most of the time patients with STD (or STI, if you prefer) complaints don’t have an IV line established, occasionally they do. My hospital stocks 1 gm and 2 gm premixed IV bags of ceftriaxone, so we just give 1 gm IV in these rare cases. But 250mg IV should be just fine.
Of course, the other way to avoid the painful injection is to mix the ceftriaxone with lidocaine... or avoid contracting gonorrhea altogether.
References:
Product Information: ROCEPHIN(R) IV, IM injection, ceftriaxone sodium IV, IM injection. Genentech USA, Inc. (per Manufacturer), South San Francisco, CA, 2010.
Workowski KA, Berman S; Centers for Disease Control and Prevention (CDC). Sexually transmitted diseases treatment guidelines, 2010. MMWR Recomm Rep 2010;59(RR-12):1-110. [
Interesting take on this info, but it still may not be entirely accurate. Although the plasma concentrations are nearly identical, the URINE concentrations remain almost twice as high for IM injections over 24-48 hours according to the same product insert. In fact, that info comes in the chart that immediately follows the one you mentioned above in the original literature. This means that IM MAY work better for clearing urethritis. Please note that for the pediatric infections where the indication is listed IV/IM, these are all presumed bacteremic situations, where the antibiotics are being given for a minimum of 7 days, not just for a single dose. Even for kids, single dose treatments are listed as IM.
ReplyDeleteDr. Radtke, thank you for your insightful comment. I did not address this in the post, but perhaps should have. According to the Clinical and Laboratory Standards Institute (CLSI), the generally accepted MIC cutoff for ceftriaxone susceptibility is between 1 and 4 mcg/mL (depending on the bacterium). Even if the urine concentrations are less with IV vs IM (15 vs 28 mcg/mL) at 24-48 hours after a 0.5 gm dose, there is still sufficient urinary concentration via the IV route. Also another reason we usually give a 1 gm premix bag if via IV.
DeleteDr. Can I use rocephin I.V in muscle as (i.m)..
ReplyDeleteIs it any risks ??
Just one Dose 1amp.
I would think that the large volume of the IV solution may be too large to be useful for IM injection.
Deletehttp://www.globalrph.com/ceftriaxone_dilution.htm