When might medicine be used to treat a pituitary tumor?

For certain small pituitary tumors, medicines may stop the tumor from growing. Or medicines can be used to keep it from making hormones that affect other parts of the body.

Medicines can’t destroy the tumor completely. But they can control hormone production. And in some cases, they can help shrink the tumor.

What types of medicines are used to treat pituitary tumors?

Many different kinds of medicines are used to treat these tumors. The type used depends on the type of pituitary tumor. It also depends on the type of hormone, and how much of it, the tumor makes.  

Tumors that make prolactin

These tumors are most often treated with medicines that stop them from making prolactin and help shrink the tumor or keep it from growing. Many times dopamine agonist medicines are the only treatment needed. These are the medicines most often used. They're taken as pills:

• Cabergoline

• Bromocriptine

After a few months of treatment, tests will be done to see if the medicine is working. Blood tests are used to measure your prolactin levels. You may also have an MRI to look at the size of the tumor.  

Sometimes the tumor goes away, and the medicine can be stopped. But you'll be watched closely to see if it comes back. In other cases, you may need the medicine for the rest of your life.

Tumors that make somatotropin or growth hormone

These tumors are often first treated with surgery. If hormone levels are still high after surgery, somatostatin analog medicines may be used. These medicines are given as injections:

• Octreotide

• Lanreotide

• Pasireotide

• Pegvisomant (a GH antagonist may be used if these other medicines don't work)

High doses of cabergoline or bromocriptine (both pills) may also be taken along with one of these medicines.

Tumors that make corticotropin (ACTH)

These tumors are most often treated with surgery, and sometimes with radiation. Because it can take radiation a long time to work, medicines may be used in the meantime. But medicines alone don't work well for these kinds of tumors. And they often have serious side effects if taken for a long time. Medicines that may be used include:

• Ketoconazole (pill)

• Mitotane (pill)

• Metyrapone (pill)

• Osilodrostat (pill)

• Aminoglutethimide (pill)

• Pasireotide (injection)

• Etomidate (injection)

• Mifepristone (pill)

If these medicines don't work, cabergoline or bromocriptine (both pills) may be tried.

Tumors that make gonadotropin (FSH/LH)

The hormones made by these very rare tumors don't cause any symptoms. They tend to be found when they're big and causing problems by pushing on nerves and the brain. Because of the size, surgery and maybe radiation afterward are preferred treatments. Regular scans will be done to see if the tumor comes back. If radiation and surgery don't work, these medicines might be given:

• Cabergoline (pill)

• Bromocriptine (pill)

• Octreotide (injection)

• Lanreotide (injection)

Tumors that make thyrotropin (TSH)

These rare tumors are treated with surgery, and maybe radiation afterwards. If there's still too much thyrotropin, medicines may be needed. Medicines most often used include:

• Octreotide (injection)

• Lanreotide (injection)

• Cabergoline (pill)

• Bromocriptine (pill)

Tumors that don't make hormones

These tumors tend to not cause problems until they're big. Surgery and radiation are the first treatments used. But if those don't work, these medicines may be used to try to slow the growth of these tumors:

• Cabergoline (pill)

• Bromocriptine (pill)

• Octreotide (injection)

• Lanreotide (injection)

• Pasireotide (injection)

What are common side effects of medicines used to treat pituitary tumors?

The medicines used to treat pituitary tumors cause side effects. Side effects depend on which medicine is used and what the dose is. They can include things like:

• Upset stomach (nausea)

• Dizziness

• Tiredness

• Vomiting

• Diarrhea or constipation

• Depression

• Headache

More serious, but less common side effects include:

• Problems with the heart valves

• Gallstones

• Diabetes

• Liver damage

Working with your healthcare provider

It's important to know which medicines you're taking. Write down the names of your medicines and ask your healthcare team how they work and what side effects they might have.

Talk with your healthcare providers about what signs to look for and when to call them. For example, some medicines can cause nausea and vomiting, which can be treated. Make sure you know what number to call with questions. Is there a different number for evenings and weekends and holidays?

It may be helpful to keep a diary of your side effects. Write down any changes you notice–physical, thinking, and emotional changes. A written list will make it easier for you to remember your questions when you go to your appointments. It will also make it easier for you to work with your healthcare team to make a plan to manage side effects.