Medications and Drugs
Pharmacy Author: Omudhome Ogbru, PharmD
Medical and Pharmacy Editor: Jay W. Marks, MD
GENERIC NAME: hydroxychloroquine
BRAND NAME: Plaquenil
DRUG CLASS AND MECHANISM: Hydroxychloroquine is classified as an
anti-malarial drug. It is similar to
chloroquine (Aralen) and is useful in
treating several forms of malaria as well as lupus erythematosus and rheumatoid
arthritis. Its mechanism of action is unknown. Malaria parasites invade human
red blood cells. Hydroxychloroquine may prevent malaria parasites from breaking
down (metabolizing) hemoglobin in human red blood cells. Hydroxychloroquine is
effective against the malarial parasites Plasmodium vivax, P. malariae, P.
ovale, and susceptible strains of P. falciparum. Hydroxychloroquine prevents
inflammation caused by lupus erythematosus and rheumatoid arthritis. The FDA
approved hydroxychloroquine in April 1955.
PRESCRIPTION: Yes
GENERIC AVAILABLE: Yes
PREPARATIONS: Tablet: 200 mg.
STORAGE: Hydroxychloroquine should be stored at room temperature up to
30 C (86 F) in a sealed, light resistant container.
PRESCRIBED FOR: Hydroxychloroquine is used for the treatment of
malaria due to Plasmodium vivax, P. malariae, P. ovale, and susceptible strains
of P. falciparum. It is also used for treating rheumatoid arthritis, and chronic
discoid and systemic lupus erythematosus when other therapies have failed. It
may prevent relapse and relieve skin inflammation, hair loss, mouth sores,
fatigue, and joint pain caused by systemic lupus erythematosus.
DOSING: The usual adult dose for treating malaria is 800 mg initially,
followed by 400 mg 6 hours later then 400 mg on days 2 and 3. The dose for
malaria prevention is 400 mg every week starting 1 or 2 weeks before exposure
and for 4 weeks after leaving the high risk area.
The recommended adult dose for
rheumatoid arthritis is 400-600 mg daily for 4-12 weeks followed by 200-400 mg
daily.
Systemic lupus erythematosus is treated with 400 mg once or twice daily
for several weeks then 200-400 mg daily. Hydroxychloroquine should be taken with
food or milk in order to reduce stomach upset.
DRUG INTERACTIONS: Administration of hydroxychloroquine with
penicillamine (Cuprimine,
Depen) may increase penicillamine levels, increasing the risk of
penicillamine side effects. The mechanism is unknown. Combining telbivudine (Tyzeka)
and hydroxychloroquine may increase the risk of unexplained muscle pain,
tenderness, or weakness because both drugs cause such side effects.
PREGNANCY: Hydroxychloroquine should only be used in
pregnant women
for malaria prophylaxis or treatment.
NURSING MOTHERS: Hydroxychloroquine may be secreted in
breast milk and
may cause side effects in the infant.
SIDE EFFECTS: Side effects include irritability, headache, weakness,
hair lightening or loss, stomach upset, nausea, dizziness, muscle pain, rash and
itching. Rarely, hydroxychloroquine can affect the bone marrow leading to
reduced white blood cells (leukopenia) or platelets (thrombocytopenia) and
abnormal red blood cells (anemia). Rare but potentially serious eye toxicity can
occur. This toxicity affects a part of the eye called the retina and can lead to
color blindness and even loss of vision. An ophthalmologist (eye specialist)
often can detect changes in the retina that suggest toxicity before serious
damage occurs. Therefore, regular eye examinations, even when there are no
symptoms, are mandatory. Patients who are genetically deficient in a certain
enzyme, called G6PD, can develop a severe
anemia resulting from the rupture of
red blood cells. This enzyme deficiency is more common in persons of African
descent and can be evaluated by blood testing. Hydroxychloroquine may worsen
psoriasis.
Reference: FDA Prescribing Information
Last Editorial Review: 1/14/2009
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
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