May 26, 2017
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Side Effects


Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice.

In a 12-week placebo-controlled monotherapy study (Study 1; WHO Group 1; functional class IIIII), the most commonly reported adverse reactions that occurred in patients receiving Orenitram included: headache, diarrhea, nausea,, and flushing. Table 1 lists the most common adverse reactions that occurred at a rate on Orenitram at least 5% higher than on placebo.

Orenitram patients in Table 1 for Study 1 (N = 151) had access to 0.25 mg tablets at randomization. Approximately 91% of such patients experienced an adverse reaction, but only 4% discontinued therapy for an adverse reaction (compared to 3% receiving placebo). The overall discontinuation rate for any reason was 17% for active and 14% for placebo.

Table 1: Adverse Reactions with Rates at Least 5% Higher on Orenitram Monotherapy than on Placebo

Reaction Orenitram
Headache 63% 19%
Diarrhea 30% 16%
Nausea 30% 18%
Flushing 15% 6%
Pain in jaw 11% 4%
Pain in extremity 14% 8%
Hypokalemia 9% 3%
Abdominal discomfort 6% 0%

Orenitram was studied in a long-term, open-label extension study in which 824 patients were dosed for a mean duration of approximately 2 years. About 70% of patients continued treatment with Orenitram for at least a year. The mean dose was 4.2 mg BID at one year.

The adverse reactions were similar to those observed in the placebo-controlled trials. The safety of Orenitram was also evaluated in an open-label study transitioning patients from Remodulin. The safety profile during this study was similar to that observed in the three pivotal studies.

Read the Orenitram (extended release osmotic tablet) Side Effects Center for a complete guide to possible side effects


Antihypertensive Agents Or Other Vasodilators

Concomitant administration of Orenitram with diuretics, antihypertensive agents or other vasodilators increases the risk of symptomatic hypotension.


Treprostinil inhibits platelet aggregation; there is increased risk of bleeding, particularly among patients receiving anticoagulants.

Effect Of CYP2C8 Inhibitors

Co-administration of Orenitram and the CYP2C8 enzyme inhibitor gemfibrozil in healthy adult volunteers increases exposure to treprostinil. Reduce the starting dose of Orenitram to 0.125 mg BID and use 0.125 mg BID increments every 3 to 4 days [see DOSAGE AND ADMINISTRATION and CLINICAL PHARMACOLOGY].

This monograph has been modified to include the generic and brand name in many instances.

Last reviewed on RxList: 1/25/2017

Side Effects

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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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