During clinical trials, adverse events were classified as follows: (1) adverse events during dose initiation and escalation, (2) adverse events during chronic dosing, and (3) adverse events associated with the drug delivery system.

Adverse Events During Dose Initiation and Escalation: During early clinical trials, FLOLAN was increased in 2-ng/kg/min increments until the patients developed symptomatic intolerance. The most common adverse events and the adverse events that limited further increases in dose were generally related to vasodilation, the major pharmacologic effect of FLOLAN. The most common dose-limiting adverse events (occurring in ≥ 1% of patients) were nausea, vomiting, headache, hypotension, and flushing, but also include chest pain, anxiety, dizziness, bradycardia, dyspnea, abdominal pain, musculoskeletal pain, and tachycardia. Table 3 lists the adverse events reported during dose initiation and escalation in decreasing order of frequency.

Table 3. Adverse Events During Dose Initiation and Escalation

Adverse Events During Chronic Administration: Interpretation of adverse events is complicated by the clinical features of PPH and PH/SSD, which are similar to some of the pharmacologic effects of FLOLAN (e.g., dizziness, syncope). Adverse events probably related to the underlying disease include dyspnea, fatigue, chest pain, edema, hypoxia, right ventricular failure, and pallor. Several adverse events, on the other hand, can clearly be attributed to FLOLAN. These include headache, jaw pain, flushing, diarrhea, nausea and vomiting, flu-like symptoms, and anxiety/nervousness.

Adverse Events During Chronic Administration for PPH: In an effort to separate the adverse effects of the drug from the adverse effects of the underlying disease, Table 4 lists adverse events that occurred at a rate at least 10% different in the 2 groups in controlled trials for PPH.

Table 4. Adverse Events Regardless of Attribution Occurring in Patients With PPH With ≥ 10% Difference Between FLOLAN and Conventional Therapy Alone

Thrombocytopenia has been reported during uncontrolled clinical trials in patients receiving FLOLAN.

Table 5 lists additional adverse events reported in PPH patients receiving FLOLAN plus conventional therapy or conventional therapy alone during controlled clinical trials.

Table 5. Adverse Events Regardless of Attribution Occurring in Patients With PPH With < 10% Difference Between FLOLAN and Conventional Therapy Alone

Adverse Events During Chronic Administration for PH/SSD: In an effort to separate the adverse effects of the drug from the adverse effects of the underlying disease, Table 6 lists adverse events that occurred at a rate at least 10% different in the 2 groups in the controlled trial for patients with PH/SSD.

Table 6. Adverse Events Regardless of Attribution Occurring in Patients With PH/SSD With ≥ 10% Difference Between FLOLAN and Conventional Therapy Alone

Table 7 lists additional adverse events reported in PH/SSD patients receiving FLOLAN plus conventional therapy or conventional therapy alone during controlled clinical trials.

Table 7. Adverse Events Regardless of Attribution Occurring in Patients With PH/SSD With < 10% Difference Between FLOLAN and Conventional Therapy Alone

Although the relationship to FLOLAN administration has not been established, pulmonary embolism has been reported in several patients taking FLOLAN and there have been reports of hepatic failure.

Adverse Events Attributable to the Drug Delivery System: Chronic infusions of FLOLAN are delivered using a small, portable infusion pump through an indwelling central venous catheter. During controlled PPH trials of up to 12 weeks' duration, up to 21% of patients reported a local infection and up to 13% of patients reported pain at the injection site. During a controlled PH/SSD trial of 12 weeks' duration, 14% of patients reported a local infection and 9% of patients reported pain at the injection site. During long-term follow-up in the clinical trial of PPH, sepsis was reported at least once in 14% of patients and occurred at a rate of 0.32 infections/patient per year in patients treated with FLOLAN. This rate was higher than reported in patients using chronic indwelling central venous catheters to administer parenteral nutrition, but lower than reported in oncology patients using these catheters. Malfunctions in the delivery system resulting in an inadvertent bolus of or a reduction in FLOLAN were associated with symptoms related to excess or insufficient FLOLAN, respectively (see ADVERSE REACTIONS: Adverse Events During Chronic Administration).

Observed During Clinical Practice: In addition to adverse reactions reported from clinical trials, the following events have been identified during post-approval use of FLOLAN. Because they are reported voluntarily from a population of unknown size, estimates of frequency cannot be made. These events have been chosen for inclusion due to a combination of their seriousness, frequency of reporting, or potential causal connection to FLOLAN.

Blood and Lymphatic: Anemia, hypersplenism, pancytopenia, splenomegaly.

Endocrine and Metabolic: Hyperthyroidism.

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.

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