There are several oral medications for the treatment of psoriasis. These medications are generally used when the topical medication fail to work of if the psoriasis is moderate to severe. Because most of these oral medications have a fair number of side effects they are always used with caution. The classes of oral medications for psoriasis include:
Antibiotics: There are some types of psoriasis (Guttate) which occur after a strep throat infection and thus some physicians give antibiotics to most individuals with psoriasis. However, it is not known whether the antibiotic decreases the symptoms of psoriasis or lessens the severity. Continuous prescription of antibiotics also leads to resistance to the drug.
Retinoids: These medications are derivatives of Vitamin A and decrease the increased cell production which is a common feature of psoriasis. The drug is often given to individuals with moderate to severe psoriasis. Despite their effectiveness, Retinoids should be used with caution in all women of child bearing age. Retinoids have a strong link to causing fetal damage in pregnant females. All women who take Retinoids must avoid getting pregnant for at least 3 years. Most physicians ask patients to sign a release form before prescribing this drug. These agents are frequently combined with phototherapy. The prescription of this drug is monitored stringently by the FDA.
Psoriasis is considered to be an immune disorder and systemic immunosuppressive drugs (e.g., methotraxate, cyclosporine) and biologic therapy (e.g., alefacept, efalizumab, etanercept, infliximab) has been recommended for individuals with extensive, widespread, or resistant disease. These drugs are never the first choice and are often used as second line therapy.
Methotraxate: Methotraxate is an older immunosuppressive drug and works by decreasing the cell turnover in psoriasis. it also reduces the redness and inflammation. In low doses the drug is well tolerated but it has potent side effects and its use has to be regularly monitored. Besides liver damage it can also decrease the number of red cells and platelets in the body. To prevent the toxicity of methotraxate, one should take folic acid at the same time. The drug is not recommended for anyone with liver disease or in pregnant females.
Azathioprine: Azathioprine, like methotraxate, is an older immunosuppressive drug. It is used for persistent psoriasis or when other therapies fail. Even though it is effective in relieving the symptoms of psoriasis, the drug has potent side effects which include suppressing the bone marrow, vomiting, easy bruising and development of cancer.
Cyclosporine: Cyclosporine is a relatively new immunosuppressive agent and very effective for resistant psoriasis. The drug is now widely used to suppress the immune system in individuals who receive organ transplants. However the drug does have some side effects like excess hair growth, hypertension, seizures, thickening of lips and kidney damage. It has to be carefully monitored and it should not be used for more than 6-12 months.
Hydroxyurea: This older medication is not as widely used. It is cheaper and mild acting. It is frequently combined with light therapy to treat moderate degrees of psoriasis. It can drop the blood counts and cause bleeding in the skin. None of the immunosuppressive drugs should be administered to pregnant females
Immunomodulator drugs: In the last decade several newer drugs have been developed to treat a wide variety of immune related disorders. These drugs can modulate the immune system and include alefacept (Amevive), efalizumab (Raptiva), etanercept (Enbrel) and infliximab (Remicade). These drugs are also known as TNF blockers. The drugs are given by intravenous infusion and are usually used for individuals who have failed to respond to traditional therapy or for those who have severe deforming psoriatic arthritis. They are effective but they also have potent side effects and the risk of allergic reaction is ever present. They are extremely expensive.
The decision which drug usually depends on the severity of psoriasis. In general, the drugs with the lowest side effects are started first.