A1,
A2,
B,
C1,
C2,
D,
E,
F,
G-H,
I-K,
L,
M,
N,
O,
P1,
P2,
Q-R,
S,
T,
U-V,
W-Z
Zithromax Side Effects, and Drug Interactions - Zithromax
Zithromax Side Effects, and Drug Interactions - Zithromax
SIDE EFFECTS
In clinical trials of intravenous azithromycin for community-acquired
pneumonia, in which 2-5 I.V. doses were given, most of the reported side effects
were mild to moderate in severity and were reversible upon discontinuation of
the drug. The majority of patients in these trials had one or more comorbid
diseases and were receiving concomitant medications. Approximately 1.2% of the
patients discontinued intravenous ZITHROMAX therapy, and a total of 2.4% discontinued
azithromycin therapy by either the intravenous or oral route because of clinical
or laboratory side effects.
In clinical trials conducted in patients with pelvic inflammatory
disease, in which 1-2 I.V. doses were given, 2% of women who received monotherapy
with azithromycin and 4% who received azithromycin plus metronidazole discontinued
therapy due to clinical side effects.
Clinical side effects leading to discontinuations from these
studies were most commonly gastrointestinal (abdominal pain, nausea, vomiting,
diarrhea), and rashes; laboratory side effects leading to discontinuation were
increases in transaminase levels and/or alkaline phosphatase levels.
Clinical
Overall, the most common side effects associated with treatment
in adult patients who received I.V./P.O. ZITHROMAX in studies of community-acquired
pneumonia were related to the gastrointestinal system with diarrhea/loose stools
(4.3%), nausea (3.9%), abdominal pain (2.7%), and vomiting (1.4%) being the
most frequently reported. Approximately 12% of patients experienced a side effect
related to the intravenous infusion; most common were pain at the injection
site (6.5%) and local inflammation (3.1%).
The most common side effects associated with treatment in adult
women who received I.V./P.O. ZITHROMAX® in studies of pelvic
inflammatory disease were related to the gastrointestinal system. Diarrhea (8.5%)
and nausea (6.6%) were most commonly reported, followed by vaginitis (2.8%),
abdominal pain (1.9%), anorexia (1.9%), rash and pruritus (1.9%). When azithromycin
was co-administered with metronidazole in these studies, a higher proportion
of women experienced side effects of nausea (10.3%), abdominal pain (3.7%),
vomiting (2.8%), application site reaction, stomatitis, dizziness, or dyspnea
(all at 1.9%).
No other side effects occurred in patients on the multiple
dose I.V./P.O. regimen of ZITHROMAX® in these studies with a
frequency greater than 1%.
Side effects that occurred with a frequency of 1% or less included
the following:
Gastrointestinal: dyspepsia, flatulence, mucositis,
oral moniliasis, and gastritis
Nervous System: headache, somnolence
Allergic: bronchospasm
Special Senses: taste perversion
Post-Marketing Experience
Adverse events reported with azithromycin during the post-marketing
period in adult and/or pediatric patients for which a causal relationship may
not be established include:
Allergic: Arthralgia, edema, urticaria and angioedema.
Cardiovascular: Arrhythmias including ventricular tachycardia
and hypotension. There have been rare reports of QT prolongation and torsades
de pointes.
Gastrointestinal: Anorexia, constipation, dyspepsia,
flatulence, vomiting/diarrhea rarely resulting in dehydration, pseudomembranous
colitis, pancreatitis, oral candidiasis and rare reports of tongue discoloration.
General: Asthenia, paresthesia, fatigue, malaise and
anaphylaxis (rarely fatal).
Genitourinary: Interstitial nephritis and acute renal
failure and vaginitis.
Hematopoietic: Thrombocytopenia.
Liver/Biliary: Abnormal liver function including hepatitis
and cholestatic jaundice, as well as rare cases of hepatic necrosis and hepatic
failure, some of which have resulted in death.
Nervous System: Convulsions, dizziness/vertigo, headache,
somnolence, hyperactivity, nervousness, agitation and syncope.
Psychiatric: Aggressive reaction and anxiety.
Skin/Appendages: Pruritus, rarely serious skin reactions
including erythema multiforme, Stevens-Johnson Syndrome and toxic epidermal
necrolysis.
Special Senses: Hearing disturbances including hearing
loss, deafness and/or tinnitus and rare reports of taste perversion.
Laboratory Abnormalities:
Significant abnormalities (irrespective of drug relationship)
occurring during the clinical trials were reported as follows: with an incidence
of 4-6%, elevated ALT (SGPT), AST (SGOT), creatinine with an incidence of 1-3%,
elevated LDH, bilirubin with an incidence of less than 1%, leukopenia, neutropenia,
decreased platelet count, and elevated serum alkaline phosphatase
When follow-up was provided, changes in laboratory tests appeared
to be reversible.
In multiple-dose clinical trials involving more than 750 patients
treated with ZITHROMAX (I.V./P.O.), less than 2% of patients discontinued azithromycin
therapy because of treatment-related liver enzyme abnormalities.
DRUG INTERACTIONS
Co-administration of nelfinavir at steady-state with a single
oral dose of azithromycin resulted in increased azithromycin serum concentrations.
Although a dose adjustment of azithromycin is not recommended when administered
in combination with nelfinavir, close monitoring for known side effects of azithromycin,
such as liver enzyme abnormalities and hearing impairment, is warranted. (See
ADVERSE REACTIONS.)
Azithromycin given by the oral route did not affect the prothrombin
time response to a single dose of warfarin. However, prudent medical practice
dictates careful monitoring of prothrombin time in all patients treated with
azithromycin and warfarin concomitantly. Concurrent use of macrolides and warfarin
in clinical practice has been associated with increased anticoagulant effects.
Drug interaction studies were performed with azithromycin and
other drugs likely to be co-administered. (See CLINICAL
PHARMACOLOGY-Drug-Drug Interactions.) When used in therapeutic doses,
azithromycin had a modest effect on the pharmacokinetics of atorvastatin, carbamazepine,
cetirizine, didanosine, efavirenz, fluconazole, indinavir, midazolam, rifabutin,
sildenafil, theophylline (intravenous and oral), triazolam, trimethoprim/sulfamethoxazole
or zidovudine. Co-administration with efavirenz or fluconazole had a modest
effect on the pharmacokinetics of azithromycin. No dosage adjustment of either
drug is recommended when azithromycin is coadministered with any of these agents.
Interactions with the drugs listed below have not been reported
in clinical trials with azithromycin; however, no specific drug interaction
studies have been performed to evaluate potential drug-drug interaction. Nonetheless,
they have been observed with macrolide products. Until further data are developed
regarding drug interactions when azithromycin and these drugs are used concomitantly,
careful monitoring of patients is advised:
Digoxin - elevated digoxin concentrations.
Ergotamine or dihydroergotamine - acute ergot toxicity characterized
by severe peripheral vasospasm and dysesthesia.
Terfenadine, cyclosporine, hexobarbital and phenytoin - elevated
concentrations.
Laboratory Test Interactions
There are no reported laboratory test interactions.
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