by on April 22, 2012
Brand Names:Rheumatrex Dose Pack, Trexall, Amethopterin and TMX
Generic name:methotrexate
Pregnancy Category:C
Half-life:15 hours

What is Methotrexate?

Methotrexate may be sold under the brand name, Rheumatrex and is used to inhibit the growth of certain cells within the body, including cells that grow quickly, such as cancer, bone marrow and skin cells. It is a powerful drug that is often used when other forms of treatment have failed.

Other brand names include Trexall, Amethopterin and TMX. Bedford Laboratories, Ben Venue Laboratories, Amresco and TCI America are some of the known manufacturers of the drug in the US.

It usually comes in tablet form but is also available in liquid or injectable form. Tablet form comes in 2.5 mg preparation. Adult patients with rheumatoid arthritis usually start with 7.5 mg to 10 mg (3 to 4 pills) taken once a week. It is usually increased to 20 mg to 25 mg a week. In cases where higher doses are needed or when patient experiences several side effects, injectable doses in 25 mg/ml preparation is given. Pediatric patients with juvenile rheumatoid arthritis usually take a dosage based on the patient’s body weight. The drug is given once a week for psoriasis, while dosage and frequency varies for cancer and other autoimmune diseases.

Methotrexate Uses

Methotrexate is used to treat breast, skin, head and neck cancer and lung cancers.  It is also used in patients who suffer from severe psoriasis and rheumatoid arthritis and autoimmune diseases such as Crohn’s disease, Lupus and multiple sclerosis.  It is classified as an antimetabolite drug, which works by halting abnormal cell division, causing tumors to shrink.  These drugs may be cell-cycle specific, meaning that they only affect cells currently in the dividing stage, or non-cell-cycle specific, meaning that they affect all cells. Methotrexate is cell-cycle specific and works by preventing cells from dividing.

MethotrexateFull benefits of the drug can be achieved only after 12 weeks of continuous treatment.

Before Taking the Medication

It is important that you talk to your doctor and thoroughly discuss with him your medical history.

Methotrexate is contraindicated in pregnant women as it may cause serious birth defects. It is also not used in nursing mothers because the medication is passed through breast milk. If you are female and about to take the drug, you need to undergo a pregnancy test. If you are male, you and your partner still need to use certain forms of birth control until after three months of treatment.  Pediatric patients under 12 years old need to be closely monitored for increased neurotoxicity when taken for acute lymphocytic leukemia. Precautionary measures are needed for patients aged 60 years and up.

Special Precautions

Before taking the drug, inform your doctor of any known food or drug allergies. Special precautions must be taken in patients with liver disease, kidney disease, lung disease, bone marrow or blood cell disorders, suppressed immune system or alcohol use. Your doctor should also know about intestinal or stomach diseases, folic acid deficiency, active infection or exposure to chicken pox. The medication causes hypersensitivity to the sun so skin should always be protected when outdoors. The drug should not be taken when pregnant, planning to be pregnant within 3 months after treatment or breastfeeding. Immunizations should also be avoided while under medication.

Nausea, vomiting and abnormal live test function are the most common side effects. Methotrexate may cause drowsiness, dizziness, decreased appetite, headache, hair loss, red eyes and swollen or tender gums. A small percentage of patients report developing mouth sores, diarrhea, skin rash, abnormal blood count and increased sensitivity to sunlight. Call your doctor immediately if you experience confusion, loss of consciousness, blurred or loss of vision, muscle weakness, difficulty moving one or both sides of the body or experience a seizure. In rare cases, patients with poor liver function may develop cirrhosis and those with poor lung function may develop lung problems.