Chemical formula: C₉H₁₁NO₅ Molecular mass: 213.189 g/mol PubChem compound: 92974
There are no available data on use of droxidopa in pregnant women and risk of major birth defects or miscarriage. Droxidopa did not produce significant reproductive toxicity in pregnant female rats or rabbits or in their fetuses. However, when pregnant female rats were dosed during days 7-17 of gestation (the period of fetal organogenesis) with doses of droxidopa corresponding to 0.3, 1 and 3 times the maximum recommended daily dose of 1,800 mg in a 60 kg patient, based on body surface area, and when their male and female offspring (who were exposed only during fetal life) were subsequently bred, the female offspring exhibited a dose-dependent reduction in the number of live fetuses across all three doses and an increased number of embryonic/fetal deaths at the two higher doses (see Data).
The estimated background risk of major birth defects and miscarriage in the indicated population is unknown. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively.
During a multigenerational reproductive toxicity study in rats, pregnant females were dosed during days 7-17 of gestation (the period of fetal organogenesis) with doses of droxidopa corresponding to 0.3, 1 and 3 times the maximum recommended daily dose of 1,800 mg in a 60 kg patient. Reduced weight gain, renal lesions, and a small number of deaths were observed in females treated with the two higher doses. When their male and female offspring (who were exposed to droxidopa only during fetal life) were subsequently bred, the female offspring exhibited a dose-dependent reduction in the number of live fetuses across all three doses and an increased number of embryonic/fetal deaths at the two higher doses.
There is no information regarding the presence of droxidopa or its active metabolite(s) in human milk, the effects of droxidopa on the breastfed child, nor the effects of droxidopa on milk production/excretion. Droxidopa is present in rat milk with peak concentrations seen 4 hours after oral drug administration and drug excretion into milk still occurring 48 hours after administration (see Data). However, due to species-specific differences in lactation physiology, animal lactation data typically do not reliably predict levels in humans. Because of the potential for serious adverse reactions, including reduced weight gain in breastfed infants, advise a woman not to breastfeed during treatment with droxidopa.
In rats, oral administration of droxidopa resulted in excretion into breast milk with peak concentrations seen 4 hours after administration, and excretion still occurring 48 hours after administration. When the drug was administered to nursing dams during the period of lactation at a dose corresponding to 3 times the maximum recommended daily dose of 1,800 mg in a 60 kg patient when based on body surface area, reduced weight gain and reduced survival were observed in the offspring. Despite the observed decreased weight gain, physical development was normal (with respect to timing and organ morphology).
Long-term studies have been conducted at dosages up to 1,000 mg/kg/day in mice and up to 100 mg/kg/day in rats with no indication of carcinogenic effects. Based on dose per unit body surface area, these two doses correspond to approximately 3 and 0.5 times, respectively, the maximum recommended total daily dose of 1,800 mg in a 60 kg patient. Droxidopa was clastogenic in Chinese hamster ovary cells (chromosome aberration assay), but was not mutagenic in bacteria (Ames assay), and was not clastogenic in a mouse micronucleus assay.
Studies in rats show that droxidopa has no effect on fertility.
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.
The safety evaluation of droxidopa is based on two placebo-controlled studies 1 to 2 weeks in duration (Studies 301 and 302), one 8-week placebo-controlled study (Study 306), and two long-term, open-label extension studies (Studies 303 and 304). In the placebo-controlled studies, a total of 485 patients with Parkinson’s disease, multiple system atrophy, pure autonomic failure, dopamine beta-hydroxylase deficiency, or non-diabetic autonomic neuropathy were randomized and treated, 245 with droxidopa and 240 with placebo.
The most commonly observed adverse reactions (those occurring at an incidence of greater than 5% in the droxidopa group and with at least a 3% greater incidence in the droxidopa group than in the placebo group) in droxidopa-treated patients during the three placebo-controlled trials were headache, dizziness, nausea, and hypertension. The most common adverse reactions leading to discontinuation from droxidopa were hypertension or increased blood pressure and nausea.
Table 1. Most Common Adverse Reactions Occurring More Frequently in the Droxidopa Group:
| Study 301 and Study 302 (1 to 2 Weeks Randomized Treatment) | Study 306 (8 to 10 Weeks Randomized Treatment) | |||
|---|---|---|---|---|
| Placebo (N=132) | Droxidopa (N=131) | Placebo (N=108) | Droxidopa (N=114) | |
| n (%) | n (%) | n (%) | n (%) | |
| Headache | 4 (3.0) | 8 (6.1) | 8 (7.4) | 15 (13.2) |
| Dizziness | 2 (1.5) | 5 (3.8) | 5 (4.6) | 11 (9.6) |
| Nausea | 2 (1.5) | 2 (1.5) | 5 (4.6) | 10 (8.8) |
| Hypertension | 0 | 2 (1.5) | 1 (0.9) | 8 (7.0) |
Note: n=number of patients. Adverse reactions that were reported in greater than 5% of patients in the droxidopa group and with at least a 3% greater incidence in the droxidopa group than in the placebo group were from Study 306.
In the long-term, open-label extension studies, a total of 422 patients, mean age 65 years, were treated with droxidopa for a mean total exposure of approximately one year. The commonly reported adverse events were falls (24%), urinary tract infections (15%), headache (13%), syncope (13%), and dizziness (10%).
The following adverse reactions have been identified during post-approval use of droxidopa. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.
Cardiac Disorders: Chest pain
Eye Disorders: Blurred vision
Gastrointestinal Disorders: Pancreatitis, abdominal pain, vomiting, diarrhea
General Disorders and Administration Site Conditions: Fatigue
Nervous System Disorders: Cerebrovascular accident
Psychiatric Disorders: Psychosis,hallucination, delirium, agitation, memory disorder
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