Kanamycin

C18H36N4O11, and antibiotic

Common side effects include changes in hearing (either hearing loss or ringing in the ears), toxicity to kidneys, and allergic reactions to the drug.

Wikipedia: http://en.wikipedia.org/wiki/Kanamycin

Chemical descriptions:

National Library of Medicine: PubChem
http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?sid=8145502

Adverse effects
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?CMD=search&DB=pubmed&term=%22Kanamycin%2fadverse%20effects%22[Mesh%20Terms%3anoexp

Toxicity
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?CMD=search&DB=pubmed&term=%22Kanamycin%2ftoxicity%22[Mesh%20Terms%3anoexp

Poisoning
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?CMD=search&DB=pubmed&term=%22Kanamycin%2fpoisoning%22[Mesh%20Terms%3anoexp

Present in these vaccines:
LYMErix – lyme

a.k.a.
kanamycin A, Kantrex ®