john asked
Can I take clindamycin if I'm allergic to penicillin?
At a glance
- There is no known cross-reactivity between penicillin-type antibiotics (i.e. beta-lactam antibiotics) and clindamycin.
Answer
In most cases, yes, you can safely take clindamycin if you have a known penicillin allergy.
Clindamycin and penicillin are in different medication classes and there is no known cross-sensitivity between them.[1]
In fact, many sources recommend clindamycin as a potential alternative antibiotic in those that are allergic to penicillin (depending on what you are treating).[2]
Penicillin Allergies
In terms of antibiotic allergies, penicillin-type antibiotics are the most common class in which people have documented allergies. Many studies report that up to 10% of individuals are allergic to them.[3]
In many cases, you'll hear the term 'beta-lactam allergy' substituted for 'penicillin-allergy'. 'Beta-lactam' antibiotics contain a 'beta-lactam' ring, an important component of the overall molecular structure of the compound.
Not only does penicillin contain a 'beta-lactam' ring, but many other antibiotics do as well, including:
- Aminopenicillins (e.g. amoxicillin)
- Cephalosporins (e.g. cephalexin)
- Carbapenems (e.g. imipenem)
Overall, allergies to beta-lactam antibiotics are the most common:
"Allergic reactions to beta-lactam antibiotics are the most common cause of drug allergies in most epidemiological studies on adverse drug reactions."
If you are allergic to penicillin, there is a greater risk that you will be allergic to another class of drugs that also contain a beta-lactam ring (e.g. any of the drugs in the list above).[4]
Below are the chemical structures of two 'beta-lactam' antibiotics, penicillin and cephalexin. You can see they both are similar in structure and both contain a beta-lactam ring.
Since beta-lactam antibiotics are so similar in structure (and both contain the beta-lactam ring), it makes sense there would be a risk of allergic cross-reactivity between them. However, the exact risk of being allergic to more than one isn't well known.
Some sources report that there is nearly a 10% risk of being allergic to a cephalosporin drug if you have a known penicillin allergy. Other sources report the risk being much lower (closer to 1-2%).[5]
Nevertheless, it is pretty much agreed that there is some increased risk between most 'beta-lactam' antibiotics.
Clindamycin Allergies
Documented allergies to clindamycin are relatively rare. One study states this regarding it:
"Clindamycin may be associated with both immediate and non-immediate allergic reactions. However, the prevalence of such reactions is rare."
Serious adverse reactions, in general, with clindamycin are thought to be rare as well, occurring at rates less than 1%.[6]
Cross-Reactivity?
It isn't thought that there is an increased risk of being allergic to clindamycin if you have a known penicillin allergy. In other words, there isn't thought to be any cross-reactivity.
You can see from the molecular structure of clindamycin that it is not similar to penicillin and does not contain a beta-lactam ring.
One large review study concerning the therapeutic uses of clindamycin even states that the drug is a good alternative to penicillin in certain situations:
References
- ^ Update on the Management of Antibiotic Allergy. PubMed
- ^ Current indications for the use of clindamycin: A critical review. PubMed
- ^ The Three C’s of Antibiotic Allergy – Classification, Cross-Reactivity and Collaboration. PubMed
- ^ Hypersensitivity reactions to non beta-lactam antimicrobial agents, a statement of the WAO special committee on drug allergy. PubMed
- ^ THE FACTS ABOUT PENICILLIN ALLERGY: A REVIEW. PubMed
- ^ Update on clindamycin in the management of bacterial, fungal and protozoal infections. PubMed
