What is prazosin?
Prazosin is an alpha-adrenergic blocker that reduces urinary sphincter tone to relax the bladder and facilitate urination in dogs and cats. It can also be used to treat congestive heart failure, systemic hypertension, or pulmonary hypertension in dogs.
Prazosin is most commonly prescribed to cats during the healing period after a urinary tract obstruction. When urinary retention occurs, the muscles of the bladder and urethra can tighten (contract and relax) and cause an uncomfortable condition. These spasms and the resulting swelling can make it difficult for the cat to recover.
Prazosin may help reduce spasms and relax the bladder, making urination easier and the cat healing.
This drug may also be useful for cats with spinal cord injuries or certain types of cancer.
Prazosin is not FDA-approved for use in animals, but is commonly prescribed and recommended by veterinarians to treat feline patients. It is available in human pharmacies with a veterinary prescription. Some veterinary clinics even stock the drug.
Because prazosin for cats is usually prescribed as a generic medicine, tablet or capsule appearance may vary depending on where it is manufactured. If you have any doubts about the correctness of the medicine, contact your veterinarian or the pharmacy where you bought it.
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How does prazosin work?
Prazosin reduces the function of the pathway by which the bladder fills and stores urine. It works by reducing the ability of certain muscles to contract. It can also lower blood pressure by relaxing the muscles that line certain arteries.
It is useful for cats recovering from a urinary tract obstruction as it also relaxes the muscles of the urethra, making it easier to pass urine.
The muscles involved in storing urine in the bladder and narrowing the urethra to prevent urine flow are called smooth muscles. In contrast to leg and arm muscles, smooth muscles are not subject to voluntary control. Therefore, prazosin is unlikely to cause your cat to urinate. Instead, once your cat reaches the litter box, it’s easier to walk away.
Other types of muscle relaxants prescribed for muscle injuries due to trauma or overuse are not effective at relaxing the smooth muscles of the bladder and urethra.
How is prazosin given?
Prazosin is administered orally in the form of capsules. It can also be specially formulated in other formulations. It can be administered with or without food; however, if vomiting occurs when administered on an empty stomach, administer future doses with food. Measure liquid forms carefully.
What happens if I forget to give my pet the medication?
If you miss a dose, give it when you remember, but if it is close to the next dose, skip the missed dose and give it at the next scheduled time and return to your normal dosing schedule. Never give your pet two doses at the same time or extra doses.
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Are there any possible side effects?
Common side effects include lethargy, vomiting, diarrhea, nausea, and constipation. Serious side effects include fainting, excessive tiredness, weakness, or dizziness. Contact your veterinarian if you observe any of these signs in your pet.
Are there risk factors for this drug?
Do not use prazosin on pets that are allergic to it. It should be used with caution in pets with kidney disease or in pets with conditions that cause low blood pressure.
Some dog breeds (e.g. Collies, German Shepherds, and Collie crossbreeds) have a specific genetic mutation (MDR1) that makes them less tolerant to certain drugs. It is believed that these dogs are more susceptible to the blood pressure-lowering effects of prazosin. This drug should be used with extreme caution in MDR1-positive dogs; if administered, lower doses and increased monitoring are recommended.
Your veterinarian will advise you on the safety of using prazosin in your pet.
Are there any drug interactions I should be aware of?
There are many drugs that should be used with caution when co-administered with prazosin, including ACE inhibitors such as benazepril (Fortekor®) and enalapril (Enacard®), amlodipine, beta-blockers such as propranolol (Inderal®), clonidine (Kapvay ®), pentoxifylline, sildenafil (Viagra®) and telmisartan (Semintra®).
Tell your vet about all medications (including vitamins, supplements, or herbal medicines) your pet is taking.
Does this drug require monitoring?
Your veterinarian can monitor your pet to make sure the medication is working, including checking for proper urination or blood pressure. Your vet will tell you how often this monitoring should be done. Monitor your pet at home for serious side effects.
How do I store prazosin?
Store the capsules at room temperature, ideally between 68-77°F or 20-25°C, and protect them from moisture and light. For compound formulations, see label storage instructions.
What is prazosin used to treat cats?
Prazosin works against spasms of the bladder and urethral muscles caused by urinary tract obstruction. It makes it easier for the cat to empty the bladder and reduces the pain and discomfort associated with muscle spasms. Prazosin is most commonly used as part of treating this problem along with other treatments such as IV fluid therapy, pain management, and a special prescription diet.
Prazosin can also be used to relax the bladder and make manual voiding easier for the pet owner. This may be necessary after trauma, spinal cord injury, or surgery when a cat is unable to control its bladder.
Prazosin does not eliminate the cause of a cat’s urinary tract congestion. They can be caused by cat urine crystals, stress, or genetic predisposition. Without permanent changes, including a prescribed urinary diet and stress management, the likelihood of recurrent urinary constipation is very high.
Due to the limited documented evidence, not all veterinarians recommend prazosin as part of the treatment plan for cats with urinary tract obstruction.
Cost of prazosin for cats
Generic Prazosin capsules or tablets are typically $15-$25 for a 2-week supply. Liquid forms of the drug that are specially formulated for your cat will cost more, depending on the price charged by the pharmacy.
Brand name formulations of prazosin tend to be much more expensive, in the region of $150 for a similar 2-week supply.
What happens if my cat misses a dose of Prazosin?
If your cat misses a dose of prazosin, skip that dose and give the next dose at the right time.
Administration of prazosin may only be necessary for a few days or weeks after urinary obstruction. Do not stop taking prazosin without consulting your cat’s veterinarian. If you accidentally give too much, contact your vet immediately.
How long does it take prazosin to work in cats?
1 to 2 hours
The effects of this drug should be felt within 1 to 2 hours; However, you will not see the effects of this drug on the outside. Your vet will need to run more tests to determine if the medication is working properly.
How long can my cat stay on prazosin?
Although protocols can vary, prazosin is often only used briefly to relieve a persistent urge to urinate. This usually takes about 5-7 days. Long-term use to prevent UTIs and congestion in cats has not been shown to be beneficial.
Does prazosin make cats sleepy?
The most common side effects of prazosin are drowsiness, dizziness, lethargy, vomiting, diarrhea, nausea, or constipation. These side effects are generally minor and will go away as your cat’s body adjusts to the medication.
Does prazosin make cats pee more?
Therefore, prazosin is unlikely to cause your cat to urinate. Instead, once your cat reaches the litter box, it’s easier to walk away. Other types of muscle relaxants prescribed for muscle injuries due to trauma or overuse are not effective at relaxing the smooth muscles of the bladder and urethra.
Does prazosin cause liver damage?
Prazosin is a non-selective alpha-adrenergic antagonist (alpha-blocker) used to treat high blood pressure. Prazosin is associated with a low rate of transient elevations in serum aminotransferases and has not been clearly associated with clinically apparent acute liver injury.
Can you give a cat too much prazosin?
Overdosing with prazosin can cause tachycardia, drowsiness, decreased reflexes, fainting, or loss of consciousness. Hypotension and shock require monitoring and treatment. Kidney function may need support.
Can prazosin cause urinary problems?
Between 1985 and 1990, 58 of 1335 women (4.3%) treated in our urodynamic clinic for urinary incontinence and other urinary symptoms took prazosin. The incidence of true SUI was significantly higher in women taking prazosin (86.2%) than in the non-prazosin group (65.7%) (p less than 0.01).
How long does it take for prazosin to start working?
Some improvement can be seen within 1 to 2 weeks of starting prazosin. It may take up to 8 weeks to see the full benefit. When prazosin is working well, you may see a reduction in nightmares and an improvement in sleep.
Should prazosin be taken with food?
You can take prazosin before or after a meal, but you should aim to take your doses at the same time of day each day. This will help you remember to take your tablets regularly. You may feel dizzy when you first start taking prazosin, so it’s important to take it just before bedtime.
Can you crush prazosin for cats?
If you’re looking for another way to give your cat a pill, you could try crushing it into powder form. However, Animal Planet advises that “tablets should never be crushed or ground for adding to food or water unless recommended by your veterinarian.