Drug Facts

Drugs from A to Z Topics

Archive for the ‘Antiarrhythmics’


09/20, 2007

Antihypertensives II Receptor Antagonists Drug

Type of Drug:

Antihypertensive; blood pressure-lowering agent.

How the Drug Works:

Angiotensin II is a chemical transmitter that combines with chemical receptors in blood vessels and other tissues and causes blood vessels to constrict (narrow) and the kidneys to retain sodium and fluids. Angiotensin II receptor antagonists inhibit the action of angiotensin II and allow the blood vessels to dilate (widen) and the kidneys to eliminate extra sodium and fluids. These actions combine to help lower elevated blood pressure.

Uses:

To lower blood pressure. May be used alone or in combination with other antihypertensive agents.

Precautions:

Irbesartan, losartan: To treat diabetic nephropathy (kidney damage) in patients with type 2 diabetes and hypertension.

Valsartan: To treat heart failure in patients who cannot tolerate angiotensin­converting enzyme (ACE) inhibitors.

Race: Angiotensin II receptor antagonists may not be as effective in black patients.

Pregnancy:

First Trimester When pregnancy is detected, the patient should discontinue use as soon as possible. Use only if clearly needed and the potential benefits outweigh the possible risks to the fetus.

Second and Third Trimesters - Studies have shown a potential adverse effect on the fetus.

Breastfeeding: It is not known if angiotensin II receptor antagonists are excreted in breast milk. Because of the potential for adverse effects, a decision should be made whether to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother. Consult your doctor before you begin breastfeeding.

Children: Safety and effectiveness of irbesartan in children younger than 6 years of age have not been established. Safety and effectiveness of other agents in children younger than 18 years of age have not been established.

Elderly: Older patients may be more sensitive to the blood pressure-lowering effects of these agents.

Lab Tests: Lab tests may be required to monitor therapy. Tests include blood pressure readings, kidney function tests, liver function tests, and blood tests for electrolytes (eg, potassium).

Drug Interactions:

Tell your doctor or pharmacist if you are taking or planning to take any over- the-counter or prescription medications or dietary supplements while taking these drugs. Drug doses may need to be modified or a different drug prescribed. The following drugs and drug classes interact with these drugs:

  • Digoxin (eg, Lanoxin) (telmisartan only)
  • Indomethacin (eg, Indocin) (Iosnrtnn only)
  • Potassium-containing salt substitutes
  • Potassium-sparing diuretics (eg, spironolactone)
  • Potassium supplements (eg, K-Our)

Side Effects:

Every drug is capable of producing side effects. Many patients experience no, or minor, side effects. The frequency and severity of side effects depend on many factors including dose, duration of therapy, and individual susceptibility. Possible side effects include:

Digestive Tract: Indigestion; diarrhea; nausea; heartburn; stomach pain; vomiting.

Nervous System: Headache; dizziness; fatigue; nervousness; anxiety; sleeplessness; depression.

Respiratory System: Upper respiratory tract infection; cough; nasal congestion; sinus irritation; runny nose; sore throat; bronchitis.

Other: Rapid heartbeat; changes in blood pressure; chest, muscle, back, leg, or joint pain; muscle cramps; viral infection; swelling (fluid retention); trauma; weakness; flu; urinary tract infection; rash; protein in the urine; dizziness when rising from a sitting or lying position (orthostatic hypotension).

Guidelines for Use:

  • Dosage is individualized. Take exactly as prescribed.
  • Do not stop taking or change the dose, unless instucted by your doctor.
  • May be taken without regard to food. Take with food if stomach upset occurs.
  • Telmisartan - Do not remove tablets from blister pack until just before taking.
  • May be taken with other blood pressure-lowering agents prescribed by your doctor.
  • Maximum blood pressure-lowering effect is generally attained after 2 to 4 weeks.
  • If a dose is missed, take it as soon as possible. If several hours have passed or it is nearing time for the next dose, do not double the dose to catch up, unless instructed by your doctor. If more than one dose is missed or it is necessary to establish a new dosage schedule, contact your doctor or pharmacist.
  • May cause dizziness or drowsiness. Use caution while driving or performing other tasks requiring alertness, coordination, or physical dexterity until tolerance is determined.
  • Dehydration (eg, excess sweating, vomiting, diarrhea) may increase the blood pressure-lowering effect, causing dizziness or fainting. Notify your doctor if dizziness develops.
  • A low dose of a diuretic may be added by your doctor if blood pressure is not controlled.
  • Inform your doctor immediately if you are pregnant, become pregnant, are planning to become pregnant, or are breastfeeding.
  • Lifestyle changes (eg, stop smoking, lose weight, exercise, limit salt in diet) also help to reduce blood pressure.
  • Lab tests may be required to monitor therapy. Be sure to keep appointments.
  • Store at room temperature (68° to 77° F for eprosartan and olmesartan; 59° to 86°F for other agents) in a tightly closed container. Protect from light and moisture.

Tagged under:, , , ,

09/17, 2007

Amiodarone - Uses and Benefits - How Does Amiodarone Works?

Type of Drug:

A drug used for specific types of severe irregular heartbeats.

How the Amiodarone Works:

Amiodarone corrects and prevents the occurrence of various types of irregular heart rhythms that may lead to life-threatening situations.

Uses of The Amiodarone:

To treat certain life-threatening heart rhythm disturbances (eg, recurrent ventricular fibrillation, recurrent hemodynamically unstable ventricular tachycardia) that are not affected by other antiarrhythmics or when other drugs are not tolerated.

Unlabeled Uses: Sometimes used to treat refractory sustained or paroxysmal atrial fibrillation and paroxysmal supraventricular tachycardia, and symptomatic atrial flutter. May improve left ventricular ejection fraction, exercise tolerance, and ventricular arrhythmias in patients with congestive heart failure.

Precautions:

Potentially fatal toxicities: Amiodarone has caused pulmonary toxicity (eg, hypersehsitivity pneumonitis or interstitial/alveolar pneumonitis). Overt liver disease has been reported, resulting in a few deaths. Significant heart block or sinus bradycardia has also been reported.

Heart effects: A worsening of heart rhythm irregularities is unusual while under treatment but can occur. Amiodarone can also cause slow heart rates or occasional pauses in the heart rhythm.

Sensitivity to sunlight: Amiodarone has caused sensitivity of the skin to sun­light and to ultraviolet light. During long-term treatment, exposed skin may appear blue-gray. Risk is increased in patients with a bit with a fail complexion and in those with excessive exposure to the sun and wear protective clothing.

Pregnancy: Amiodarone can cause fetal harm when administered to a pregnant woman. There have been some reports of congenital goiter/ hypothyroidism and hyperthyroidism. Use only if clearly needed and potential benefits to the mother outweigh the possible hazards to the fetus.

Drug Interactions:

Tell your doctor or pharmacist if you are taking or if you are planning to take any over-the-counter or prescription medications or dietary supplements with amiodarone. Doses of one or both drugs may need to be modified or a different drug may need to be prescribed. The following drugs and drug classes interact with amiodarone:

  • Antiarrhythmics, other (eg, procainamide)
  • Anticoagulants (eg, warfarin)
  • Calcium channel blockers (eg, verapamil)
  • Cimetidine (eg, Tagamet)
  • Cyclosporine (eg, Neoral)
  • Digoxin (eg, Lanoxin)
  • Disopyramide (eg, Norpace)
  • Fentanyl (eg, Sublimaze)
  • Flecainide (Tambocor)
  • Methotrexate (eg, Rheumatrex)
  • Hydantoins (eg, phenytoin)
  • Quinidine (eg, Quinora)
  • Quinolones (eg, sparfloxacin)
  • Ritonavir (Norvir)

Side Effects:

Every drug is capable of producing side effects, Many amiodaro ne users experience no, or minor, side effects, The frequency and severity of side effects depend on many factors including dose, duration of therapy, and individual susceptibility. possible side effects include:

Eyes or Ocular: Appearance of halos around lights; sensitivity to light; blurred or spotty vision; dry eyes’, sensitivity to light; permanent blindness; eye discomfort; fluid accumulation at the optic disc; other vision disturbances; eye degeneration; optic nerve disease.

Digestive Tract: Nausea; vomiting; constipation; diarrhea; loss of appetite; stomach pain.

Nervous System: Tremors; twitches; fatigue; loss of coordination; unsteady walking; dizziness; numbness and tingling in hands and feet; difficulty sleeping; headache; general discomfort·, abnormal gait.

Circulatory System: Slowing of heartbeat (rhythm); worsening of irregular heart rhythm; decrease in blood pressure; decrease in blood platelets; coagulation abnormalifies; heart failure; heart block.

Respiratory System: Difficulty breathing (shortness of breath); coughing; abnormal x-ray or biopsy; fibrosis.

Skin: Sensitivity to sunlight; blue-gray skin color; rash; dermatitis; unexplained bruising; hair loss; flushing; abnormal skin sensations (eg, burning, prickling, tingling).

Other: Disturbances in thyroid, respiratory, kidney and liver function (cirrhosis, hepatitis); abnormal taste and smell; edema (fluid retention); abnormal salivation; loss of sex drive; abnormal blood tests.

Guidelines for Use:

  • Dosage is individualized. Take exactly as prescribed.
  • Do not change the dose or stop taking unless advised by your doctor.
  • High doses of amiodarone are usually required for the first 1 to 3 weeks of treatment.
  • Take with meals, especially if stomach upset Occurs.
  • If a dose is missed, take it as soon as possible. If several hours have passed or it is nearing time for the next dose, do not double the dose to catch up, unless advised by your doctor. If more than one dose is missed, or it is necessary to establish a new dosage schedule, contact your doctor or pharmacist.
  • Inform your doctor if you are pregnant, become pregnant, planning to become pregnant, or are breastfeeding before beginning therapy.
  • May cause photosensitivity (sensitivity to sunlight). Use sunscreen and wear protective clothing until tolerance is determined.
  • Shortness of breath, coughing and abnormal diagnostic tests (eg, chest x-ray, lung biopsy) can occur. Report changes in breathing or vision, or any coughing to your doctor and have a routine chest x-ray.
  • Loss of vision can occur. Inform your doctor if your vision changes or your peripheral vision decreases.
  • Store at room temperature (59 0 to 86°F). Keep in a tight container away from light.


Tagged under:, , , , ,