Flolan
Flolan - General Information
A prostaglandin that is a powerful vasodilator and inhibits platelet aggregation. It is biosynthesized enzymatically from prostaglandin endoperoxides in human vascular tissue. The sodium salt has been also used to treat primary pulmonary hypertension.
Pharmacology of Flolan
Flolan has two major pharmacological actions: (1) direct vasodilation of pulmonary and systemic arterial vascular beds, and (2) inhibition of platelet aggregation. In animals, the vasodilatory effects reduce right and left ventricular afterload and increase cardiac output and stroke volume. The effect of epoprostenol on heart rate in animals varies with dose. At low doses, there is vagally mediated brudycardia, but at higher doses, epoprostenol causes reflex tachycardia in response to direct vasodilation and hypotension. No major effects on cardiac conduction have been observed. Additional pharmacologic effects of epoprostenol in animals include bronchodilation, inhibition of gastric acid secretion, and decreased gastric emptying. No available chemical assay is sufficiently sensitive and specific to assess the in vivo human pharmacokinetics of epoprostenol.
Flolan for patients
Patients receiving FLOLAN should receive the following information: FLOLAN must be reconstituted only with STERILE DILUENT for FLOLAN. FLOLAN is infused continuously through a permanent indwelling central venous catheter via a small, portable infusion pump. Thus, therapy with FLOLAN requires commitment by the patient to drug reconstitution, drug administration, and care of the permanent central venous catheter. Sterile technique must be adhered to in preparing the drug and in the care of the catheter, and even brief interruptions in the delivery of FLOLAN may result in rapid symptomatic deterioration. A patient’s decision to receive FLOLAN should be based upon the understanding that there is a high likelihood that therapy with FLOLAN will be needed for prolonged periods, possibly years. The patient’s ability to accept and care for a permanent intravenous catheter and infusion pump should also be carefully considered.
Flolan Interactions
Additional reductions in blood pressure may occur when FLOLAN is administered with diuretics, antihypertensive agents, or other vasodilators. When other antiplatelet agents or anticoagulants are used concomitantly, there is the potential for FLOLAN to increase the risk of bleeding. However, patients receiving infusions of FLOLAN in clinical trials were maintained on anticoagulants without evidence of increased bleeding. In clinical trials, FLOLAN was used with digoxin, diuretics, anticoagulants, oral vasodilators, and supplemental oxygen.
In a pharmacokinetic substudy in patients with congestive heart failure receiving furosemide or digoxin in whom therapy with FLOLAN was initiated, apparent oral clearance values for furosemide (n = 23) and digoxin (n = 30) were decreased by 13% and 15%, respectively, on the second day of therapy and had returned to baseline values by day 87. The change in furosemide clearance value is not likely to be clinically significant. However, patients on digoxin may show elevations of digoxin concentrations after initiation of therapy with FLOLAN, which may be clinically significant in patients prone to digoxin toxicity.
Flolan Contraindications
A large study evaluating the effect of FLOLAN on survival in NYHA Class III and IV patients with CHF due to severe left ventricular systolic dysfunction was terminated after an interim analysis of 471 patients revealed a higher mortality in patients receiving FLOLAN plus conventional therapy than in those receiving conventional therapy alone. The chronic use of FLOLAN in patients with CHF due to severe left ventricular systolic dysfunction is therefore contraindicated.
Some patients with pulmonary hypertension have developed pulmonary edema during dose initiation, which may be associated with pulmonary veno-occlusive disease. FLOLAN should not be used chronically in patients who develop pulmonary edema during dose initiation.
FLOLAN is also contraindicated in patients with known hypersensitivity to the drug or to structurally-related compounds.
Additional information about Flolan
Flolan Indication: For the long-term intravenous treatment of primary pulmonary hypertension and pulmonary hypertension associated with the scleroderma spectrum of disease in NYHA Class III and Class IV patients who do not respond adequately to conventional therapy.
Mechanism Of Action: Prostaglandins are present in most body tissues and fluids and mediate many biological functions. Flolan is a member of the family of prostaglandins that is derived from arachidonic acid. The major pharmacological actions of epoprostenol are mediated via inhibition of platelet aggregation.
Drug Interactions: Not Available
Food Interactions: Not Available
Generic Name: Epoprostenol
Synonyms: PGI2; Prostacyclin; Prostaglandin I2
Drug Category: Antihypertensive Agents; Platelet Aggregation Inhibitors
Drug Type: Small Molecule; Approved
Other Brand Names containing Epoprostenol: Flolan;
Absorption: Not Available
Toxicity (Overdose): Symptoms of overdose are extensions of its dose-limiting pharmacologic effects and include flushing, headache, hypotension, nausea, vomiting, and diarrhea. Most events were self-limiting and resolved with reduction or withholding of epoprostenol. Single intravenous doses at 10 and 50 mg/kg (2703 and 27,027 times the recommended acute phase human dose based on body surface area) were lethal to mice and rats, respectively. Symptoms of acute toxicity were hypoactivity, ataxia, loss of righting reflex, deep slow breathing, and hypothermia.
Protein Binding: Not Available
Biotransformation: Epoprostenol is metabolized to 2 primary metabolites: 6-keto-PGF1α (formed by spontaneous degradation) and 6,15-diketo-13,14-dihydro-PGF1α (enzymatically formed), both of which have pharmacological activity orders of magnitude less than epoprostenol in animal test systems. Fourteen additional minor metabolites have been isolated from urine, indicating that epoprostenol is extensively metabolized in humans.
Half Life: The in vitro half-life of epoprostenol in human blood at 37°C and pH 7.4 is approximately 6 minutes; the in vivo half-life of epoprostenol in humans is therefore expected to be no greater than 6 minutes.
Dosage Forms of Flolan: Injection, powder, for solution Intravenous
Chemical IUPAC Name: 5-[(3aR,4R,5R,6aS)-5-hydroxy-4-[(E,3S)-3-hydroxyoct-1-enyl]-3,3a,4,5,6,6a-hexahydrocyclopenta[d]furan-2-ylidene]pentanoic acid
Chemical Formula: C20H32O5
Epoprostenol on Wikipedia: https://en.wikipedia.org/wiki/Epoprostenol
Organisms Affected: Humans and other mammals