Sildenafil Paste
Sildenafil is a compounded formulation containing Sildenafil, prepared by Mixlab for veterinary use. Available by prescription.
Paste medications are thick and sticky, usually given by mouth using a syringe or tube. They’re often used for dewormers or other oral meds in horses, dogs, and cats. The key is to aim for the back of the mouth so your pet swallows the paste instead of spitting it out.
For Horses:
- Set the dose on the syringe if it has markings (usually based on weight).
- Stand beside your horse, not in front, and have someone hold them if possible.
- Gently insert your thumb into the side of the horse’s mouth (between the teeth) to open it.
- Insert the syringe into that gap and squirt the paste toward the back of the tongue.
- Lift the horse’s head slightly and encourage swallowing by stroking the throat or gently blowing on the nostrils.
- Watch for licking or chewing—that means they swallowed. If paste spills out, check how much was lost and contact your vet if unsure.
- You can offer a little water afterward and reward them with a treat like a carrot if allowed.
For Dogs & Cats:
- Gently open your pet’s mouth or slip the syringe into the side of it.
- Aim toward the back of the tongue and squirt the paste in.
- Hold the mouth closed briefly, and rub the throat or blow gently on the nose to encourage swallowing.
- Give praise or a treat afterward to make it a positive experience.
Aftercare:
- Wipe your pet’s mouth if needed.
- Clean or recap the syringe as instructed.
- Store the tube according to label directions.
Tip: Paste can feel weird to pets at first. For horses, try giving applesauce by syringe ahead of time so they get used to the sensation.
The uses and pharmacology described below reflect the FDA-approved labeling for this active ingredient; your veterinarian determines whether and how they apply to your animal's treatment plan.
Veterinarians most commonly consider sildenafil when a patient is presented with clinical signs of pulmonary hypertension—a condition characterized by elevated blood pressure within the arteries of the lungs. It is frequently a point of discussion for pets with concurrent congestive heart failure or those experiencing chronic respiratory tissue stress. By modulating the biochemical signals that govern blood vessel diameter, your veterinarian can manage the physiological environment of the pulmonary system during periods of cardiovascular strain.
At a pharmacological level, sildenafil acts by selectively inhibiting the PDE5 enzyme, which is found in high concentrations within the smooth muscle of pulmonary blood vessels. This inhibition leads to increased levels of cyclic guanosine monophosphate (cGMP), a molecule that mediates smooth muscle relaxation. The result is vasodilation—the widening of the blood vessels—which allows for a decrease in pulmonary vascular resistance and a more normal flow of blood through the lungs. Your veterinarian will determine whether sildenafil is appropriate for your pet based on weight, diagnostic imaging results and the specific cardiovascular management objectives.
Prescription only. Use only under the direction of a licensed veterinarian. This information is not a substitute for veterinary diagnosis, prescribing or monitoring. Compounded drugs are not approved by the FDA for safety or effectiveness.
Commonly observed effects of sildenafil include gastrointestinal changes such as decreased appetite, vomiting or loose stools. Some animals may exhibit skin flushing, particularly on the ears or abdomen, due to the medication’s vasodilatory profile. Because sildenafil influences systemic blood pressure, your veterinarian will monitor for signs of blood pressure shifts, such as weakness or lethargy. If you observe significant fainting episodes (syncope), persistent coughing or signs of physical distress, contact your veterinarian promptly.
This medication is typically used with extra caution or avoided in patients with known systemic hypotension (low blood pressure) or those with severe renal or hepatic impairment. It is also carefully evaluated in patients with active pulmonary edema or significant dehydration. Before starting a protocol involving sildenafil, ensure your veterinarian has a complete history of all other prescriptions and supplements your pet is receiving, as it may interact with other vasodilators or medications used for heart disease. Your veterinarian is the right person to design a comprehensive monitoring plan and provide guidance on the necessary diagnostic follow-ups to ensure the management approach remains suitable for your pet's individual health status.
Yes. Sildenafil is a prescription medication and can only be dispensed by a licensed pharmacy upon receipt of a valid authorization from a licensed veterinarian. Mixlab verifies all authorizations before any medication is prepared or shipped to your home.
Yes. While sildenafil is available in various commercial tablet formats, Mixlab can compound this medication into specialized strengths or alternative flavored dosage forms—such as oral liquids, gourmeds or flavored chews—if your veterinarian determines a customized preparation better suits your pet's needs. The decision between a commercial and compounded product rests with the prescribing veterinarian.
Veterinarians commonly consider sildenafil for dogs experiencing pulmonary hypertension, which can be a complication of both heart and lung disease. It is used to help manage the pressure in the vessels of the lungs, which may support more normal respiratory effort and exercise tolerance in affected patients.
Owners should monitor for signs of digestive upset, such as vomiting or a change in appetite, as well as any unusual redness of the skin or ears. Because the medication affects blood pressure, it is also important to report any episodes of weakness or fainting to your veterinarian to ensure the management plan remains appropriate.
