Friday, September 18, 2009

30 - Drugs that May Reduce Combined Hormonal Contraceptive Efficacy



Interacting Drug

Documentation

Antituberculous
 

  Rifampin

Established; reduced efficacy if 50 microg EE

Antifungals
 

  Griseofulvin

Strongly suspected

Anticonvulsants and sedatives
 

  Phenytoin, mephenytoin, phenobarbital, primidone, carbamzepine, ethosuximide

Strongly suspected; reduced efficacy if 50 microg EE; trials lacking

Antibiotics
 

  Tetracycline, doxycycline

Two small studies find no association

  Penicillins

No association documented

  Ciprofloxacin

No effect on efficacy of a 30 microg EE + desogestrel pill

  Ofloxacin

No effect on efficacy of a 30 microg EE + levonorgestrel pill

Antiretrovirals

Variable effects; see manufacturer or other


EE = ethinyl estradiol.

29 - Drugs Whose Effectiveness Is Influenced by Combination Oral Contraceptives



Interacting Drug

Documentation

Management

Analgesics
 
 

  Acetaminophen

Adequate

Larger doses of analgesic may be required

  Aspirin

Probable

Larger doses of analgesic may be required

  Meperidine

Suspected

Smaller doses of analgesic may be required

  Morphine

Probable

Larger doses of analgesic may be required

Anticoagulants
 
 

  Dicumarol, warfarin

Controversial
 

Antidepressants
 
 

  Imipramine

Suspected

Decrease dosage about a third

Tranquilizers
 
 

  Diazepam, alprazolam

Suspected

Decrease dose

  Temazepam

Possible

May need to increase dose

  Other benzodiazepines

Suspected

Observe for increased effect

Anti-inflammatories
 
 

  Corticosteroids

Adequate

Watch for potentiation of effects, decrease dose accordingly

Bronchodilators
 
 

  Aminophylline, theophylline, caffeine

Adequate

Reduce starting dose by a third

Antihypertensives
 
 

  Cyclopenthiazide

Adequate

Increase dose

  Metoprolol

Suspected

May need to lower dose

Other
 
 

  Troleandomycin

Suspected liver damage

Avoid

  Cyclosporine

Possible

May use smaller dose

  Antiretrovirals

Variable

See manufacturer or other

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