Serious cold calls for serious meds:
Most common side-effects [of Clarithromycin] are gastrointestinal: Diarrhea, nausea, extreme irritability, abdominal pain and vomiting, facial swelling. Less common side-effects include headaches, hallucinations (auditory and visual), dizziness/motion sickness, rashes, alteration in senses of smell and taste, including a metallic taste that lasts the entire time one takes it. Dry mouth, panic and / or anxiety attacks and nightmares have also been reported albeit less frequently. In more serious cases it has been known to cause jaundice, cirrhosis, and kidney problems including renal failure. Uneven heartbeats, chest pain, and shortness of breath have also been reported while taking this drug.
Clarithromycin may cause false positives on urine drug screens for cocaine.
Adverse effects of clarithromycin in the central nervous system include dizziness, ototoxicity and headaches, but delirium and mania are also uncommon side effects.
When taken along with some statins, drugs used to reduce blood serum cholesterol levels, muscle pain may occur.
There is also the risk of oral candidiasis, due to the increased yeast production in the body from the antibiotics.
Wikipedia entry on Clarithromycin [wikipedia.org]