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
Rifadin Side Effects, and Drug Interactions - Rifampin
Rifadin Side Effects, and Drug Interactions - Rifampin
SIDE EFFECTS
Gastrointestinal
Heartburn, epigastric distress, anorexia, nausea, vomiting, jaundice, flatulence,
cramps, and diarrhea have been noted in some patients. Although Clostridium
difficile has been shown in vitro to be sensitive to rifampin, pseudomembranous
colitis has been reported with the use of rifampin (and other broad spectrum
antibiotics). Therefore, it is important to consider this diagnosis in patients
who develop diarrhea in association with antibiotic use. Rarely, hepatitis or
a shock-like syndrome with hepatic involvement and abnormal liver function tests
has been reported.
Hematologic
Thrombocytopenia has occurred primarily with high dose intermittent therapy,
but has also been noted after resumption of interrupted treatment. It rarely
occurs during well supervised daily therapy. This effect is reversible if the
drug is discontinued as soon as purpura occurs. Cerebral hemorrhage and fatalities
have been reported when rifampin administration has been continued or resumed
after the appearance of purpura.
Rare reports of disseminated intravascular coagulation have been observed.
Transient leukopenia, hemolytic anemia, and decreased hemoglobin have been
observed.
Central Nervous System
Headache, fever, drowsiness, fatigue, ataxia, dizziness, inability to concentrate,
mental confusion, behavioral changes, pain in extremities, and generalized numbness
have been observed.
Psychoses has been rarely reported.
Ocular
Visual disturbances have been observed.
Endocrine
Menstrual disturbances have been observed.
Rare reports of adrenal insufficiency in patients with compromised adrenal
function have been observed.
Renal
Elevations in BUN and serum uric acid have been reported. Rarely, hemolysis,
hemoglobinuria, hematuria, interstitial nephritis, acute tubular necrosis, renal
insufficiency, and acute renal failure have been noted. These are generally
considered to be hypersensitivity reactions. They usually occur during intermittent
therapy or when treatment is resumed following intentional or accidental interruption
of a daily dosage regimen, and are reversible when rifampin is discontinued
and appropriate therapy instituted.
Dermatologic
Cutaneous reactions are mild and self-limiting and do not appear to be hypersensitivity
reactions. Typically, they consist of flushing and itching with or without a
rash. More serious cutaneous reactions which may be due to hypersensitivity
occur but are uncommon.
Hypersensitivity Reactions
Occasionally, pruritus, urticaria, rash, pemphigoid reaction, erythema multiforme
including Stevens-Johnson Syndrome, toxic epidermal necrolysis, vasculitis,
eosinophilia, sore mouth, sore tongue, and conjunctivitis have been observed.
Anaphylaxis has been reported rarely.
Miscellaneous
Rare reports of myopathy and muscular weakness have also been observed.
Edema of the face and extremities has been reported. Other reactions reported
to have occurred with intermittent dosage regimens include "flu syndrome" (such
as episodes of fever, chills, headache, dizziness, and bone pain), shortness
of breath, wheezing, decrease in blood pressure and shock. The "flu syndrome"
may also appear if rifampin is taken irregularly by the patient or if daily
administration is resumed after a drug free interval.
DRUG INTERACTIONS
ENZYME INDUCTION: Rifampin is known to induce certain cytochrome P-450 enzymes.
Administration of rifampin with drugs that undergo biotransformation through
these metabolic pathways may accelerate elimination of coadministered drugs.
To maintain optimum therapeutic blood levels, dosages of drugs metabolized by
these enzymes may require adjustment when starting or stopping concomitantly
administered rifampin.
Rifampin has been reported to accelerate the metabolism of the following drugs:
anticonvulsants (eg, phenytoin), antiarrhythmics (eg, disopyramide, mexiletine,
quinidine, tocainide), oral anticoagulants, antifungals (eg, fluconazole, itraconazole,
ketoconazole), barbiturates, beta-blockers, calcium channel blockers (eg, diltiazem,
nifedipine, verapamil), chloramphenicol, clarithromycin, corticosteroids, cyclosporine,
cardiac glycoside preparations, clofibrate, oral or other systemic hormone contraceptives,
dapsone, diazepam, doxycycline, fluoroquinolones (eg ciprofloxacin), haloperidol,
oral hypoglycemic agents (sulfonylureas), levothyroxine, methadone, narcotic
analgesics, nortriptyline, progestins, quinine, tacrolimus, theophylline tricyclic
antidepressants (eg, amitriptyline, nortriptyline), and zidovudine. It may be
necessary to adjust the dosages of these drugs if they are given concurrently
with rifampin.
Patients using oral or other systemic hormonal contraceptives should be advised
to change to nonhormonal methods of birth control during rifampin therapy.
Rifampin has been observed to increase the requirements for anticoagulant drugs
of the coumarin type. In patients receiving anticoagulants and rifampin concurrently,
it is recommended that the prothrombin time be performed daily or as frequently
as necessary to establish and maintain the required dose of anticoagulant.
Diabetes may become more difficult to control.
OTHER INTERACTIONS: When the two drugs were taken concomitantly, decreased
concentrations of atovaquone and increased concentrations of rifampin were observed.
Concurrent use of ketoconazole and rifampin has resulted in decreased serum
concentrations of both drugs. Concurrent use of rifampin and enalapril has resulted
in decreased concentrations of enalaprilat, the active metabolite of enalapril.
Dosage adjustments should be made if indicated by the patient's clinical condition.
Concomitant antacid administration may reduce the absorption of rifampin. Daily
doses of rifampin should be given at least 1 hour before the ingestion of antacids.
Probenecid and cotrimoxazole have been reported to increase the blood level
of rifampin.
When rifampin is given concomitantly with either halothane or isoniazid, the
potential for hepatotoxicity is increased. The concomitant use of rifampin and
halothane should be avoided. Patients receiving both rifampin and isoniazid
should be monitored close for hepatotoxicity.
Plasma concentrations of sulfapyridine may be reduced following the concomitant
administration of sulfasalazine and rifampin. This finding may be the result
of alteration in the colonic bacteria responsible for the reduction of sulfasalazine
to sulfapyridine and mesalamine.
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