Phenylpropanolamine

Indications

For the control of urinary incontinence due to urethral sphincter hypotonus in dogs.

Dosage and Administration

The recommended dosage is 2 to 4 mg/kg (0.9 to 1.8 mg/lb) of body weight once daily according to Table 1 below. Administer PROIN ER with food (see Clinical Pharmacology ). Do not split or crush tablets. Dogs weighing less than 10 pounds cannot be safely dosed because tablet administration would result in a dose over 4 mg/kg. Table 1. Dose Administration a Body weight in pounds PROIN ER 10-20 18 mg 21-40 38 mg 41-80 74 mg 81-125 b 145 mg a Body weight should be rounded to the nearest pound. b Dogs exceeding 125 lbs should receive the appropriate combination of tablets to achieve the recommended dosage. Dogs may transition from PROIN® Chewable Tablets to PROIN ER without a break in administration. However, do not alternate PROIN ER with PROIN Chewable Tablets because the effectiveness and safety of interchangeable use have not been evaluated.

Warnings

Not for human use. Keep out of reach of children. Consult a physician in case of accidental ingestion by humans. Keep PROIN ER in a secured location out of reach of dogs, cats, and other animals to prevent accidental ingestion or overdose.

Precautions

Proin ER may mask signs of incontinence due to urinary tract infection. PROIN ER is not effective in dogs with incontinence due to neurologic disease or malformations. PROIN ER may cause hypertension; therefore, use with caution in dogs with pre-existing heart disease, hypertension, liver disease, kidney insufficiency, diabetes, glaucoma, and conditions with a predilection for hypertension. Use with caution in dogs receiving sympathomimetic drugs, tricyclic antidepressants, or monoamine oxidase inhibitors as increased toxicity may result. Use with caution in dogs administered halogenated gaseous anesthetics as this may increase the risk of cardiac arrhythmias. A laboratory study on human blood revealed that phenylpropanolamine (PPA) used in conjunction with aspirin may potentiate decreased platelet aggregation. 1 PROIN ER may cause increased thirst; therefore, provide dogs with ample fresh water. The safe use of PROIN ER has not been evaluated in dogs that are intended for breeding, or that are pregnant or lactating.

Adverse Reactions

Adverse Reactions are listed below for both PROIN ER (NADA Number 141-517) and PROIN Chewable Tablets (NADA 141-324). PROIN ER (NADA 141-517) In the open-label clinical study involving 119 dogs administered PROIN ER once a day for 180 days, the following adverse reactions were observed. Table 2. Number and percentage of dogs with adverse reactions in the 180-day open-label clinical study for PROIN ER Adverse Reactions Total N = 119 Emesis 39 (32.8%) Body weight loss (≥5%) 34 (28.6%) Hypertension (≥160 mmHg) developed during study a 15 (12.6%) Diarrhea 20 (16.8%) Proteinuria 16 (13.4%) Tachycardia (≥160 bpm) 11 (9.2%) Lethargy 11 (9.2%) Decreased appetite 10 (8.4%) Urinary Tract Infection 10 (8.4%) Elevated Alkaline phosphatase and/or Alanine Aminotransferase 7 (6.0%) Hypoglycemia 4 (3.3%) Hypercalcemia 3 (2.5%) Increased BUN 2 (1.7%) Bradycardia (<60 bpm) 2 (1.7%) Seizures/twitching 2 (1.7%) a There were an additional 21 dogs enrolled with hypertension who remained hypertensive throughout the study. During the first week of administration of PROIN ER, 15% of dogs had reported emesis, diarrhea, or decreased appetite which improved or resolved prior to the Day 21 visit. Four deaths occurred during the study. One dog was euthanized for pulmonary metastasis and one dog for poor quality of life due to hindlimb weakness. One dog had emesis and died at home; upon necropsy a foreign body was present in the small intestine. The fourth dog had been treated for a urinary tract infection three weeks prior to sudden death of undetermined cause. PROIN Chewable Tablets (NADA 141-324): Table 3 below includes the most common adverse reactions observed in the masked, placebo-controlled 28-day clinical study involving 123 PROIN Chewable Tablet-treated dogs and 61 placebo-treated dogs. In addition, one dog exhibited disorientation, nervousness, a 7.7% loss of body weight, and hypertension with proteinuria. A second dog exhibited restless behavior, lethargy, a 2.8% body weight loss, and proteinuria. Table 3. Number and percentage of dogs with adverse reactions in the 28-day placebo-controlled clinical study for PROIN Chewable Tablets Adverse Reactions PROIN Treated (N=123) Placebo Treated (N=61) Emesis 20.3% 8.2% Hypertension (≥ 160mm Hg) a 19.5% 14.7% Anorexia 16.3% 3.3% Body weight loss (> 5%) b 16.1% 6.8% Proteinuria 13.0% 8.2% Anxiety/aggression/behavior change 9.7% 3.2% Diarrhea 7.3% 9.8% Polydipsia 6.5% 9.8% Lethargy 5.7% 1.6% Musculoskeletal Disorder 3.2% 1.6% Insomnia/Sleep Disorder 2.5% 0.0% a One or more systolic blood pressure readings of ≥160mmHg. b The "N" for weight loss is PROIN-treated N=118 and placebo N=59 because seven dogs did not have a final weight at the time of withdrawal from the study. One-hundred fifty-seven dogs continued into the 6-month open-label clinical study for PROIN Chewable Tablets. The most common adverse reactions are listed in Table 4 below. In addition, one dog exhibited progressively worsening hypertension with proteinuria. Five dogs enrolled in the study with pre-existing heart disease. Of these, one dog developed systolic failure with an unknown relation to treatment. Table 4: Number and percentage of dogs with adverse reactions in the 6-month open-label clinical study for PROIN Chewable Tablets Adverse Reactions Total N= 125 Hypertension (≥ 160 mmHg) a 34.6% Body Weight Loss (> 5%) 24.8% Emesis 19.7% Proteinuria 15.3% Anorexia 10.2% Diarrhea 6.4% Lethargy 5.7% Anxiety/ behavior change/ aggression 5.7% a Percent of dogs with systolic blood pressures of ≥ 160 mmHg on day -7 were 30.2% and on day 0 were 33.3%. Post Approval Experience for PROIN Chewable Tablets (2015): The following adverse reactions are based on voluntary, post approval reporting for PROIN Chewable Tablets (2015). Not all adverse events are reported to FDA/CVM. It is not always possible to reliably estimate the adverse event frequency or establish a causal relationship to product exposure using these data. The signs reported are listed in decreasing order of reporting frequency by body system: Gastrointestinal: Emesis, anorexia, diarrhea, hypersalivation Behavioral: Agitation, lethargy, vocalization, confusion General body system: Polydipsia, weight loss, weakness, fever Respiratory: Panting Dermatological: Erythema, piloerection Hepatic: Elevated serum alanine aminotransferase (ALT), elevated serum alkaline phosphatase (ALP) Neurologic: Ataxia, seizures, tremors Renal/Urinary: Renal failure, hematuria, urinary retention Cardiovascular: Tachycardia, hypertension, bradycardia, arrhythmias Sensory: Ophthalmic disorders, mydriasis and eye redness In some cases, death, including euthanasia, has been reported. Sudden death was sometimes preceded by neurologic signs, vocalization, or collapse. A necropsy of one dog revealed subarachnoidal and intraventricular hemorrhage in the brain. The following signs have been reported more often with a dose higher than the recommended dosage: agitation, arrhythmia, bradycardia, erythema, fever, hypersalivation, hypertension, lethargy, mydriasis, panting, piloerection, tachycardia, tremor, and urinary retention. For a copy of the Safety Data Sheet (SDS) or to report suspected adverse drug events, contact Pegasus Laboratories at 1-800-874-9764. For additional information about adverse drug experience reporting for animal drugs, contact FDA at 1-888-FDA-VETS or www.fda.gov/reportanimalae

Description

Description: PROIN ER (phenylpropanolamine hydrochloride extended-release tablets) is a sympathomimetic amine closely related to ephedrine. Phenylpropanolamine hydrochloride (PPA) is the nonproprietary designation for benzenemethanol, a-(1-aminoethyl)-hydrochloride, (R*, S*)-, (±). The empirical formula is C9H13NO•HCl and the molecular weight is 187.67. It is a white crystalline compound having a slight aromatic odor. PPA is freely soluble in water and alcohol but is practically insoluble in ether, benzene and chloroform. The chemical structure of phenylpropanolamine hydrochloride is: image description

Information for Owners

Always follow the dosage instructions for PROIN ER provided by your veterinarian. Give PROIN ER with food and do not split or crush the tablet. Monitor your dog after giving PROIN ER to be sure all of it was consumed. If you have difficulty giving PROIN ER, contact your veterinarian. PROIN ER may cause increased thirst; therefore, provide dogs with ample fresh water. If you forget to give your dog a dose, then resume dosing at the next scheduled dose. Keep PROIN ER in a secured location out of reach of dogs, cats, and other animals to prevent accidental ingestion or overdose. Contact your veterinarian immediately if the dog ingests more tablets than prescribed or if other pets ingest PROIN ER. In the case of accidental ingestion by humans, contact a physician immediately. Contact your veterinarian if you notice restlessness, irritability, loss of appetite, the incontinence persists or worsens, or any other unusual signs. Consult your veterinarian before administering PROIN ER with any other medications.

Storage

Store at controlled room temperature 20-25°C (68-77°F), excursions permitted between 15-40°C (59-104°F)

Other labels for this ingredient

These labels are also stored for the same active ingredient. They are not identical to the one reprinted above, and each is listed by product and set id rather than merged with it.

• DESCRIPTION:, Pegasus Laboratories, Inc.. Set id 6096f709-fa5a-45e1-9767-2f159f882520.
• DESCRIPTION:, Pegasus Laboratories, Inc.. Set id 98861d71-98c2-4f47-be86-825a46fb7634.
• DESCRIPTION:, Pegasus Laboratories, Inc.. Set id c26843de-74ba-4a51-a18c-2d3bc0bcb07a.
• Phenylpropanolamine Hydrochloride Chewable Tablets, ZYVET ANIMAL HEALTH INC.. Set id a2843a87-265e-4d47-a89b-bee88107b0a6.
• UriPropamine TM (phenylpropanolamine hydrochloride) Chewable Tablets, MWI ( VetOne). Set id c1ddf3b2-0b6d-4974-9c6d-1c51d4bab340.
• Pegasus Laboratories, Inc. Pegasus Laboratories, Inc. Pegasus Laboratories, Inc. Cheng Fong Chemical Co Ltd PhenylPro 75 phenylpropanoloamine hydrochloride PHENYLPROPANOLAMINE HYDROCHLORIDE PHENYLPROPANOLAMINE Scored on one side PPA;75 For oral use in dogs only, Pegasus Laboratories, Inc.. Set id 070aa5ff-efd6-4114-86a0-34baf5e646b2.
• Pegasus Laboratories, Inc. Pegasus Laboratories, Inc. Pegasus Laboratories, Inc. Cheng Fong Chemical Co Ltd PhenylPro 25 phenylpropanoloamine hydrochloride PHENYLPROPANOLAMINE HYDROCHLORIDE PHENYLPROPANOLAMINE Scored on one side PPA;25 For oral use in dogs only, Pegasus Laboratories, Inc.. Set id 4570140d-b887-475b-8ad5-a9c4aa3f7e6e.
• Pegasus Laboratories, Inc. Pegasus Laboratories, Inc. Pegasus Laboratories, Inc. Cheng Fong Chemical Co Ltd PhenylPro 50 phenylpropanoloamine hydrochloride PHENYLPROPANOLAMINE HYDROCHLORIDE PHENYLPROPANOLAMINE scored on one side PPA;50 For oral use in dogs only, Pegasus Laboratories, Inc.. Set id 8d740bb6-5177-4a25-8cbd-8c1f42214b41.
• Description:, Pegasus Laboratories, Inc.. Set id 089bde88-521a-401e-8f03-1320e7e6ae03.
• Description:, Pegasus Laboratories, Inc.. Set id 0b2249cb-ecf4-4be9-a6b2-0fe6ca2a7a36.
• Description:, Pegasus Laboratories, Inc.. Set id ea1b0dc1-bd3d-4762-9f27-4300e4606d3d.

FDA adverse event reports

The FDA Center for Veterinary Medicine publishes the adverse event reports it receives through openFDA. The counts below are the reports naming phenylpropanolamine as an active ingredient for each species this label names, as returned on 2026-09-16, coded by the VeDDRA reaction term the reporter chose. Reactions are counted per report, so one report can appear under several terms.

These are counts, not rates. Reporting is voluntary, the number of animals treated is not known, and a widely used product accumulates reports for that reason alone. A report records that an event followed a dose; it does not establish that the product caused it. The counts say nothing about how one product compares with another.