Antiprotozoal drugs
Definition
Antiprotozoal drugs are medicines that treat infections caused by protozoa.
Purpose
Antiprotozoal drugs are used to treat a variety of diseases caused by
protozoa. Protozoa are animal-like, one-celled animals, such as amoebas. Some
are parasites that cause infections in the body. African sleeping sickness,
giardiasis, amebiasis, Pneumocystis cariniipneumonia (PCP), and malaria
are examples of diseases caused by protozoa.
Description
Antiprotozoal drugs come in liquid, tablet, and injectable forms and are
available only with a doctor's prescription. Some commonly used antiprotozoal
drugs are metronidazole (Flagyl), eflornithine (Ornidyl), furazolidone (Furoxone),
hydroxychloroquine (Plaquenil), iodoquinol (Diquinol, Yodoquinol, Yodoxin), and
pentamidine (Pentam 300).
Recommended dosage
The recommended dosage depends on the type of antiprotozoal drug, its
strength, and the medical problem for which it is being used. Check with the
physician who prescribed the drug or the pharmacist who filled the prescription
for the correct dosage. Always take antiprotozoal drugs exactly as directed.
Precautions
Some people feel dizzy, confused, lightheaded, or less alert when using these
drugs. The drugs may also cause blurred vision and other vision problems. For
these reasons, anyone who takes these drugs should not drive, use machines or do
anything else that might be dangerous until they have found out how the drugs
affect them.
The antiprotozoal drug furazolidone may cause very dangerous side effects
when taken with certain foods or beverages. Likewise, metronidazole (Flagyl) can
cause serious liver damage if taken with alcohol. Check with the physician who
prescribed the drug or the pharmacist who filled the prescription for a list of
products to avoid while taking these medicines.
Anyone who has ever had unusual reactions to antiprotozoal drugs or related
medicines should let his or her physician know before taking the drugs again.
The physician should also be told about any allergies to foods, dyes,
preservatives, or other substances.
Some antiprotozoal drugs may cause problems with the blood. This can increase
the risk of infection or excessive bleeding. Patients taking these drugs
shouldbe careful not to injure their gums when brushing or flossing their teeth
or using a toothpick. They shouldcheck with the physician before having any
dentalwork done. Care should also be taken to avoidcuts from razors, nail
clippers, or kitchen knives, orhousehold tools. Anyone who has any of these
symptoms while taking antiprotozoal drugs should call the physician immediately:
- Fever or chills
- Signs of cold or flu
- Signs of infection, such as redness, swelling, or inflammation
- Unusual bruising or bleeding
- Black, tarry stools
- Blood in urine or stools
- Pinpoint red spots on the skin
- Unusual tiredness or weakness.
Anyone taking this medicine should also check with a physician immediately if
any of these symptoms occur:
- Blurred vision or other vision changes
- Skin rash, hives, or itching
- Swelling of the neck
- Clumsiness or unsteadiness
- Numbness, tingling, pain, or weakness in the hands or feet
- Decrease in urination.
Children are especially sensitive to the effects of some antiprotozoal drugs.
Never give this medicine to a child unless directed to do so by a physician,
and always keep this medicine out of the reach of children. Use safety vials.
The effects of antiprotozoal drugs on pregnant women have not been studied.
However, in experiments with pregnant laboratory animals, some antiprotozoal
drugs cause birth defects or death of the fetus. Women who are pregnant or who
plan to become pregnant should check with their physicians before taking
antiprotozoal drugs. Mothers who are breastfeeding should also check with their
physicians about the safety of taking these drugs.
Before using antiprotozoal drugs, people with any of these medical problems
should make sure their physicians are aware of their conditions:
- Anemia or other blood problems
- Kidney disease
- Heart disease
- Low blood pressure
- Diabetes
- Hypoglycemia (low blood sugar)
- Liver disease
- Stomach or intestinal disease
- Nerve or brain disease or disorder, including convulsions (seizures)
- Psoriasis (a skin condition)
- Hearing loss
- Deficiency of the enzyme glucose-6-phosphate dehydrogenase (G6PD)
- Eye or vision problems
- Thyroid disease.
Side effects
The most common side effects are diarrhea, nausea, vomiting, and stomach
pain. These problems usually go away as the body adjusts to the drug and do not
require medical treatment.
Other rare side effects may occur. Anyone who has unusual symptoms after
taking an antiprotozoal drug should get in touch with his or her physician.
Interactions
Antiprotozoal drugs may interact with other medicines. When this happens, the
effects of one or both of the drugs may change or the risk of side effects may
be greater. Anyone who takes antiprotozoal drugs should let the physician know
all other medicines he or she is taking. Among the drugs that may interact with
antiprotozoal drugs are:
- Alcohol
- Anticancer drugs
- Medicine for overactive thyroid
- Antiviral drugs such as zidovudine (Retrovir)
- Antibiotics
- Medicine used to relieve pain or inflammation
- Amphetamine
- Diet pills (appetite suppressants)
- Monoamine oxidase inhibitors (MAO inhibitors) such as phenelzine (Nardil)
and tranylcypromine (Parnate), used to treat conditions including depression
and Parkinson's disease.
- Tricyclic antidepressants such as amitriptyline (Elavil) and imipramine
(Tofranil)
- Decongestants such as phenylephrine (Neo-Synephrine) and pseudoephedrine
(Sudafed)
- Other antiprotozoal drugs.
The list above does not include every medicine that may interact with an
antifungal drug. Be sure to check with a physician or pharmacist before
combining antifungal drugs with any other prescription or nonprescription
(over-the-counter) medicine.
Key Terms
- Amebiasis
- An infection caused by an ameba, which is a type of protozoan.
- Fetus
- A developing baby inside the womb.
- Giardiasis
- A condition in which the intestines are infected with , a type of
protozoan.
- Inflammation
- Pain, redness, swelling, and heat that usually develop in response
to injury or illness.
- Parasite
- An organism that lives and feeds in or on another organism (the
host) and does nothing to benefit the host.
- pneumonia
- A severe lung infection caused by a parasitic protozoan. The disease
mainly affects people with weakened immune systems, such as people with
AIDS.
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