Are all combined hormonal contraceptives at risk for reduced effectiveness if a patient is being treated for hepatitis?

I had a patient today looking for hormonal contraception. She is currently being treated for latent tuberculosis with Rifampin and INH for 9 months.  She and her partner are using condoms sporadically and wanted something more reliable.

Are all hormonal contraceptives at risk for reduced effectiveness if a woman is using Rifampin?  I have recommended better condom use, a ParaGard or a diaphragm, but was wondering if Mirena would also be acceptable in her case.
I’d love more information on contraception for women using Rifampin.

Thanks so much for your guidance on this topic.

A:         

Our best data on the interactions of drugs is regarding combined pills.  Rifampin taken by a woman for treatment of tuberculosis is generally said to lower the contraceptive effectiveness of pills (combined or progestin-only pills), Implanon implants, Ortho Evra patches and NuvaRings, but not Depo-Provera, Mirena or ParaGard injections effectiveness is not lowered by use of Rifampin.  

 

The question of Depo Provera effectiveness in women using anti-seizure meds or anti- tuberculosis meds was raised last week.  One of the advantages of Depo is that its effectiveness is NOT compromised by either Rifampicin or anti-seizure meds. Many anti-seizure meds are also used to treat depression, anxiety and even insomnia. Below is information from the chapter in Contraceptive Technology on injectable contraception relating to this issue:

 Injectable Contraceptives by Alisa B. Goldberg, MD, MPH and David A. Grimes, MD

8.   Minimal drug interactions. There has been no demonstrated interaction between DMPA and antibiotics or enzyme-inducing drugs. The only drug that decreases the effectiveness of DMPA is aminoglutethimide, which is usu­ally used to suppress adrenal function in selected cases of Cushing’s disease.

9.   Fewer seizures. DMPA has been found to decrease the frequency of grand mal seizures. Improvement in seizure control is probably due to the sedative properties of progestins and this effect may be mediated through gamma-aminobutyric acid (GABA) receptors in the hippocampus. Taking anti-seizure medicine has no impact on the efficacy of DMPA.

The drugs that lower and do not lower pill effectiveness are listed below:
The drugs that do and do not decrease the effectiveness of hormonal contraceptives are listed below:
Drugs that decrease pill effectiveness by increasing liver hormone breakdown:
Carbamazepine (Tegretol), Nevirapine, Oxcarbazepine (Trileptal), Phenobarbital, Phenytoin (Dilantin), Primidone (Mysoline), Rimidone (Mysoline), Rifabutin, Rifampicin, St. John’s Wort, Topiramate (Topamax), Lamotrigine (Lamictal)*
*Lamictal is, itself affected by pills and pills affect Lamictal


Drugs that do not cause induction of liver enzymes:
Sodium Valproate (Depakote, Depakene), Clonazepire,
Ampicillin, Clarithromycin, Metronidazole,    Ciproflaxacin, Ofloxacin, Doxycycline, Fluconazole, Ethosuximide (Zarontin), Levetiracetam (Keppra), Vigabatrin (Sabril), Zonigamite (Zonegram), Pregabalin (Lyrica), Clonazepam (Klonopin), Tigabine (Gabitril), Possibly ethosuximide, griseofulvin, troglitazone, Vigabatrin and Provigil (modafinal)

[Speroff, Darney; A Clinical Guide for Contraception.  Fourth edition 2005, page 101]

[Guillebaud, Contraception: Your Questions Answered; Fourth edition, Pages 123-130] [Physicians Desk Reference 2007: p.990] Broad-spectrum antibiotics:

“Broad-spectrum antibiotics such as amoxicillin and tetracycline, which alter the intestinal flora thought to be instrumental in promoting absorption of the sex steroids, do not reduce the efficacy of oral contraceptives. 

Women using the antibiotics do have statistically significant but not clinically lower serum levels of estrogen and progestins.  However, virtually every woman taking these antibiotics has remained well within the therapeutic range for the sex steroids.  168-170[Murphy 1991] [Neely 1991] [Friedman 1980]. 

As a result, back-up methods should not be necessary unless the patient has problems taking her pills, e.g., if her underlying medical condition interferes with pill taking or absorption.  Long-term use of broad-spectrum antibiotics (such as erythromycin or tetracycline for acne) is compatible with OC use; back-up methods are not routinely needed for pregnancy prevention. 171[Helms 1997].

Given all the conflicting messages, here is an attempt at summarizing, but not cutting
 through, the confusion regarding the antibiotics most women and their health care providers are most concerned about:

If you are taking a broad spectrum antibiotic such as tetracycline, doxycycline, ampicillin or erythromycin, some clinicians recommend that you use a back-up contraceptive, others do not. Some women taking these broad spectrum antibiotics use a back-up contraceptive, others do not. The decision is up to you.

Here are the words of advice from the Planned Parenthood Federation of America: “There is no pharmacologic evidence that the acute or chronic use of systemic antibiotics (e.g. tetracycline, ampicillin) decreases the efficiency of low-dose COCs in women who take them correctly.”

Her reply 12-23: “Dear Dr. Hatcher, thank you for your clear and helpful information about TB meds and hormonal contraception.  I appreciate the information and will share it with my colleagues at PPLM in Boston.”