When you're prescribed with any medication, your doctor will usually ask you about any other medicine you are taking. This is so that they can make sure you don't take anything that will interact with each other, including the contraceptive pill. There are some types of medication that cause the pill to be less effective. It's important to know which ones in case you are taking any, or are prescribed them at any point. 

How do medications affect the pill? 

When you take certain medications they cause the hormones contained in the pill to be broken down and absorbed into the bloodstream quicker than usual. This means their concentration within your blood is diluted, increasing your risk of pregnancy. 


it's a common concern that taking antibiotics might play havoc with your contraception. However, you have nothing to worry about with the majority of antibiotics. Rifampin is the only antibiotic that stops the pill from working properly. This is used to treat tuberculosis. If you're being prescribed antibiotics to treat a urinary tract infection or acne then your contraception will not be affected. 

HIV treatments 

If you have been diagnosed with HIV you may be prescribed with a type of medication called antiretrovirals. These help your immune system to fight infection and ease your symptoms. They can also help to prevent further spread of the infection to others. 

The following medications interfere with the pill: 

  • Darunavir 
  • Efavirenz 
  • Lopinavir 
  • Nevirapine 

You may wish to consider a different type of contraception if you are on any of these medications. 

Epilepsy treatments 

If you have epilepsy, you might be prescribed with anticonvulsant medication. These alter the brain chemicals which cause seizures to stop them from happening. 

Epilepsy medications which cause the pill to be less effective include: 

  • Carbamazepine 
  • Felbamate 
  • Oxcarbazepine 
  • Phenobarbital 
  • Phenytoin 
  • Primidone 
  • Topiramate 

Antifungal treatments 

Fungal infections affecting the skin, such as athlete's foot require antifungal medicines to treat them. Two types of these medicines can interact with the pill: 

  • Griseofulvin 
  • Ketoconazole 

If you have been prescribed with either of these treatments, ensure you use an additional type of contraception until you have completed your treatment and for an additional 7 days. 

Sleep disorder treatments 

A medication called Modafinil is a type of stimulant that decreases the effectiveness of the pill. It is used to treat narcolepsy and sleep apnea and works by increasing the alertness in your brain so that you can stay awake and alert during the day. 

Anxiety and insomnia treatments 

A type of medication called Barbiatures can disrupt your contraceptive pill. These were primarily prescribed for anxiety and insomnia to calm the central nervous system but they are rarely used anymore. 

Morning after pill 

If you have taken ellaOne, a form of emergency contraception, this can have an effect on your contraceptive pill. You should use an additional barrier method of contraception until your next period arrives. Alternatively, you can take another type of morning after pill known as Levonelle

Herbal remedies 

A herbal remedy called St. John's wort is another substance that can have an effect on the pill. This is predominantly used as a natural antidepressant for mild depression. It is not usually recommended by health professionals as it interacts with many types of medications. 

What should I do if I am taking any of these medications? 

If you have been prescribed a short course of any of these medications, you can use condoms, or another barrier method of contraception, for the duration of your treatment to make sure you are protected against pregnancy. 

For women on long term medication, you may wish to explore other options for contraception which is not affected by medication. These include: 

  • Condoms
  • Diaphragm or cap
  • Implant 
  • Injection 
  • IUD


Web MD > Medicines That Interfere with Birth Control Pills
Web MD > Antiretrovirals: HIV and Aids Drugs
NHS > Epilepsy Treatment
Web MD > Griseofulvin