“What medications are you taking?” is one of the important questions your doctor will ask when taking your medical history. Although prescription birth control has a very low incidence of risks, there are a number of drug interactions that can create complications.

Smoking

Although you might not normally think of a cigarette as a drug, the action of nicotine in your body is certainly drug-like. The combination of prescription birth control and smoking is the most serious drug interaction and should be avoided at all costs.

Antibiotics and Anti-fungal Medicines

Certain antibiotics and other medicines have the potential to interact negatively with birth control by reducing its effectiveness. Advise your doctor if you are taking any of the following medications. For the antibiotics, there are two general groups to consider, the penicillin group and the tetracycline group. The specific antibiotics in the penicillin group include: the amoxicillins (Amoxil, Polymox, Trimox, Wymox, Utimox, A-Cillin, Larotid, and Augmentin), the ampicillins (Principen, Omnipen, Penamp, Polycillin, Amplin, Amcill, and Totacillin), bacampicillin (Spectrobid), carbenicillin (Geocillin), the cloxacillins (Cloxapen and Tegopen), the dicloxacillins (Dynapen, Dycill, and Pathocil), the nafcillins (Nafcil, Nallpen, and Unipen), the oxacillins (Bactocill and Prostphlin), or the penicillins (Veetids, Pen Vee K, Bicillin, and Permapen.) The antibiotics in the tetracycline group include: demeclocycline (Declomycin), the doxycyclines (Doryx, Doxy, Vibramycin, and Vibra-Tabs), minocycline (Minocin), and the tetracyclines (Sumycin, Teracyn, Achromycin, Robitet, and Panmycin.) A third category of antibiotics for very serious diseases such as tuberculosis and meningitis is the rifampin group which includes: Rifadin, Fifadin IV, and Rimactane. In addition, when taking antibiotics, you should know that the risk of getting serious yeast infections increases when you are also taking prescription birth control.

Of the anti-fungal medications that can interfere with your prescription birth control is griseofulvin, marketed under the names Grisactin, Grifulvin V, and Fulvicin PG.

Barbiturates and Anti-Seizure Drugs

Another class of drugs that can reduce the effectiveness of prescription birth control is the barbiturates. Barbiturates can calm the central nervous system in order to reduce anxiety and bring on sleep. These drugs include amobarbital (Amytal), butabarbital (Butisol), mephobarbital (Mebaral), secobarbital (Seconal), and phenobarbital (Luminal, Solfoton.)

A third class of drugs, which interfere with the effectiveness of prescription birth control, includes the anti-seizure medicines phenytoin (marketed Dilantin), carbamazepine (Tegretol), and Primidone.

Other Medicines

A fourth group of drugs belong to the anti-HIV protease inhibitors called ritonavir, marketed under the name Norvir. Protease inhibitors can cause severe nausea, weakness, liver problems, and increase blood fat levels, causing heart problems.

The anti-diabetic drug, troglitazone (Rezulin) is also on the list of drugs with interactions to prescription birth control.

As you can see, it is important to give your doctor a complete list of any and all medications you take before adding prescription birth control to your list.