Imipramine represents a drug from the tricyclic antidepressants class that is extensively used in the treatment of behavioral disorders. In a particular case, Imipramine is recommended for dogs suffering from urinary incontinence. Even though this drug has been approved by the FDA for use in humans only, veterinarians are allowed to prescribe it as an extra-label drug. Dog incontinence may be caused by an infection of the urinary tract, but other causes are also possible. In such cases, passage of urine occurs mostly while the dogs sleeps, but awake dogs can also suffer from this problem.
Pharmaceutical Mechanism of Imipramine
Canine urinary incontinence is usually treated with phenylpropanolamine, but Imipramine also tends to become a popular alternative among veterinarians. In some situations these drugs are used in tandem, in order to shorten the period of the treatment and to increase the effectiveness. Imipramine has anticholinergic properties, which means that it blocks the action of a neurotransmitter called acetylcholine. This effect occurs both in the central and peripheral nervous system.
Imipramine also blocks the reabsorption of norepinephrine (noradrenaline) and serotonin. One of the consequences of this fact is the relaxation of the muscle fibers found around the bladder. When these fibers relax, urinary retention is achieved. Imipramine has been found to be particularly effective in female dogs, and is especially recommended when other drugs fail.
Availability and Recommended Dosage
This drug is available either as tablets or in injectable form. The latter has a concentration of 12.5 mg/ml, while the tablets contain 10 mg, 25 mg, 50 mg, 75 mg, 100 mg, 125 mg and 150 mg of active ingredient.
Since Imipramine is a prescription drug, it is mandatory to talk to a veterinarian prior to administering it to the dog. The veterinarian will determine the precise dosage, in concordance with the type of behavior that needs to be modified and with the severity of the symptoms. In the majority of the cases, however, the dose ranges between 0.25 and 0.5 mg per pound, administered either once or twice a day. Keep in mind that the duration of the treatment also depends on severity of the symptoms. The prescription should be completed, if the veterinarian does not suggest otherwise.
Interactions with Other Drugs
In order to prevent interactions with other drugs, you need to tell the veterinarian if the dog follows another treatment at the moment. Drug interactions have two possible consequences: either the effectiveness of the drugs drops or adverse reactions develop. Imipramine is known to interact with the following types of medication:
- Barbiturates
- Cimetidine
- Monoamine oxidase inhibitors
- Tranquilizers
The veterinarian will provide an extensive list of drugs with which Imipramine can interact.
Adverse Reactions to Imipramine
Side effects are usually noticed when the dosage is not respected with strictness, or when Imipramine interacts with other types of medication. Also, there are situations when the dogs are sensitive or even allergic to the active ingredients of the drug. In the case of Imipramine, the most frequent adverse reaction is sedation. Other side effects include:
- Agitation
- Blurred vision
- Constipation
- Dry mouth
- Postural hypotension
- Respiratory depression
- Tachycardia
If any of these adverse reactions is noticed, the veterinarian will either adjust the dosage or recommend an alternative to Imipramine.