Pill Interactions with Other Drugs

Oral Contraceptives (OC) May Interfere with the Following Medications:

MEDICATION SIGNIFICANCE† ADVERSE EFFECTS RECCOMENDATIONS

CORTICOSTEROIDS:
Hydrocortisone
Prednisone
Prednisolone

• • • • Some steroids have reduced metabolism and higher blood levels when combined with OCs. A reduction in steroid dose may be required.

THEOPHYLLINE:
Aminophylline
Oxtriphylline

• • • • OCs may raise blood levels of theophylline. The theophylline level will need to be monitored.

BENSODIASEPINES:
Alprazolam (Xanax)
Chlordiazepoxide (Librium)
Clonazepam (Klonopin)
Diazepam (Valium)
Flurazepam (Dalmane)
Triazolam (Halcion)

• • • OCs may raise blood levels of benzodiazepines. A reduction in dose of benzodiazepines may be indicated.

CAFFEINE

• • • OCs may reduce the metabolism of caffeine. Watch for signs of caffeine overdose.

BETA-BLOCKERS:
Metoprolol (Lopressor)
Propranolol (Inderal)

• • OCs may raise blood levels of beta-blockers. Monitor heart rate. Monitor dose of beta-blocker.

TRICYCLIC ANTIDEPRESSENTS:
Amitriptyline (Elavil)
Desipramine (Norpramin)
Imipramine (Tofranil)
Nortriptyline (Pamelor)

OCs may raise the blood levels of some tricyclic antidepressants. Monitor the response to the tricyclic antidepressant.

SALICYLATE (Asprin)

OCs may lower the blood levels of salicylates. Aspirin doses may need to be adjusted upwards for women on maintenance doses of salicylates.

PAIN RELIEVERS:
Acetaminophen (Tylenol)

OCs may lower the blood levels of acetaminophen. Acetaminophen and OCs may be used together with little or no risk.

Nonsteroidal Anit-Inflammatory Drugs (NSAIDs):
  Ibuprophen (Advil)
  Naproxen (Aleve)

• • • •    

CYCLOSPORIN

• • • • OCs may raise blood levels of cyclosporine increasing the risk of toxicity.  

ATORVASTIN (Lipitor)

• • • • OCs may raise atorvastin levels Monitor atorvastin

† Significance: Rated from highly significant (• • • •) to weakly significant (•).

Medications that May Interact with the Oral Contraceptive (OC):

MEDICATION SIGNIFICANCE‡ ADVERSE EFFECTS RECCOMENDATIONS

SEIZURE MEDICATIONS:
Phenytoin (Dilantin)
Felbamate (Felbatol)
Carbamazepine (Tegretol)
Barbiturates (Pentobarbital, Seco-barbital, Primidone, Butabarbital, Butalbital)

• • • • Risk of pregnancy up to 25 times higher in OC users also using anticonvulsants. Potential loss of seizure control when used as anticonvulsant.

Consider using alternative methods, altogether.

Lamictal • • • • Changes in Lamictal levels; lowered during hormone pills and raised during placebo pills  
Sodium valproate (Depakene) Does not appear to interfere with oral contraceptive therapy.  

CENTRAL NERVOUS SYSTEM:
Modafinil (Provigil)

• • • • Increased risk of pregnancy. Consider using alternative methods, altogether.

ANTIFUNGAL:
Griseofulvin (Grisactin)

• • • • Breakthrough bleeding and unintended pregnancies have been reported. Consider using alternative methods, altogether.

Ketoconazole (Nizoral)

• • Increase blood levels of OC  

ANTIBIOTICS:
Rifampin

• • • • A high incidence of menstrual irregularities and a 6% pregnancy rate is seen on OCs. Use an alternative or additional contraceptive method.

All other antibiotics

Questionable association of increased pregnancy risk. Consider using backup contraception during antibiotic treatment and for 7 days following treatment.

ST. JOHN'S WORT

• • May lower blood concentration levels of hormones that suppress ovulation. May lower blood concentration levels of hormones that suppress ovulation.

ASCORBIC ACID (Vitamin C)

May raise levels of estrogen in the blood. Estrogen-related side effects may appear with vitamin C>1 gram.

‡ Significance: Rated from highly significant (• • • •) to weakly significant (•).

Resource: 

  ePOCRATeS® RX Online. Pill inserts. Drug Facts and Comparisons. http://online.epocrates.com/

Reference:

ePOCRATeS® Rx Online 2009.