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One selection filters the source overview, clinical facts, reports and dose calculator. Literature references are not species-filtered.
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Source overview
Recorded excerpts for one species. Each dose remains a separate source entry; no regimen is selected.
Choose one species to view its source overview. All-species evidence remains available below.
View full clinical evidence and sources ↓Clinical evidence
Pending clinical review (PROPOSED)Rule-based (RULE_BASED)— applies to the facts and dose entries in this species selection; individual source records retain their own status.
Indications2
Pulmonary arterial hypertension (adjunct)
DogCatExtra-label (EXTRA_LABEL)2 source records · View provenance
- Dog · Plumb's Veterinary Drug Handbook, 7th ed., p. 1060–1061; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 726–727 — Indications table · Not applicable · Extra-label (EXTRA_LABEL) · Pending clinical review (PROPOSED) · Rule-based
Original excerpt: Pulmonary arterial hypertension (adjunct) — Extra-label
- Cat · Plumb's Veterinary Drug Handbook, 7th ed., p. 1060–1061; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 726–727 — Indications table · Not applicable · Extra-label (EXTRA_LABEL) · Pending clinical review (PROPOSED) · Rule-based
Original excerpt: Pulmonary arterial hypertension (adjunct) — Extra-label
- Dog · Plumb's Veterinary Drug Handbook, 7th ed., p. 1060–1061; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 726–727 — Indications table · Not applicable · Extra-label (EXTRA_LABEL) · Pending clinical review (PROPOSED) · Rule-based
Dose regimens3
This calculator performs arithmetic only on the sourced dosing field shown for each result — it does not verify the field's accuracy, does not select which field to use for a patient, and does not replace a veterinarian's order. Not for clinical use. Confirm every result against the primary source before dispensing.
Choose one species above to view its dose calculator.
Adverse effects124
Cutaneous flushing (inguinal area) — Reported
DogNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Dog · Plumb's Veterinary Drug Handbook, 7th ed., p. 1060–1061; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 726–727 — Side Effects / Adverse Effects table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
GI effects — Possible
Other speciesNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Other species · Plumb's Veterinary Drug Handbook, 7th ed., p. 1060–1061; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 726–727 — Side Effects / Adverse Effects table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Hypotension — Dose/combination-related
Other speciesNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Other species · Plumb's Veterinary Drug Handbook, 7th ed., p. 1060–1061; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 726–727 — Side Effects / Adverse Effects table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
These are counts of spontaneously reported events, not proven adverse effects, causal relationships, or incidence rates.
Bars compare report counts within each species; they do not show incidence.
More reportsFewer reportsDog
- Death by euthanasia12 reports
- Not eating11 reports
- Diarrhoea10 reports
- Lethargy (see also Central nervous system depression in Neurological)9 reports
- Behavioural disorder NOS7 reports
- Hyperkalaemia7 reports
- Lack of efficacy - NOS7 reports
- Lethargy (see also Central nervous system depression in 'Neurological')7 reports
- Vomiting7 reports
- Abnormal radiograph finding6 reports
- Abnormal ultrasound finding6 reports
- Death6 reports
Cat
- Cachexia2 reports
- Death by euthanasia2 reports
- Digestive tract adenocarcinoma2 reports
- Discomfort NOS2 reports
- Encephalitis2 reports
- Gastritis2 reports
- Glomerulosclerosis2 reports
- Hepatitis2 reports
- Metastatic tumour2 reports
- Necropsy performed2 reports
- Not eating2 reports
- Pulmonary fibrosis2 reports
Monitoring1
Clinical efficacy (syncope, cough, respiratory effort), pulmonary artery pressure (if measurable), systemic blood pressure
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 1060–1061; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 726–727 — Monitoring Parameters · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Contraindications1
Concurrent nitrates (nitroglycerin, isosorbide) or nitroprusside — life-threatening hypotension risk
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 1060–1061; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 726–727 — Contraindications & Warnings table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Precautions3
Pulmonary veno-occlusive disease (may worsen); resting hypotension, fluid depletion, severe LV outflow obstruction, autonomic dysfunction
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 1060–1061; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 726–727 — Contraindications & Warnings table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Set owner expectations about cost and the experimental/extrapolated nature of veterinary dosing — human erectile-dysfunction formulations are what's typically dispensed, and no veterinary-labeled product exists.
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 1060–1061; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 726–727 — Clinical pearl · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Never combine with nitrate-containing therapies — this is a hard, well-documented contraindication.
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 1060–1061; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 726–727 — Clinical pearl · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Interactions5
Nitrates/nitroprusside — Contraindicated — severe hypotension
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 1060–1061; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 726–727 — Drug Interactions table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Azole antifungals (ketoconazole, itraconazole), erythromycin/clarithromycin, cimetidine — ↓ sildenafil metabolism, ↑ levels
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 1060–1061; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 726–727 — Drug Interactions table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Alpha-blockers, amlodipine, other antihypertensives — Additive hypotension
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 1060–1061; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 726–727 — Drug Interactions table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Phenobarbital, rifampin — ↓ sildenafil levels
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 1060–1061; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 726–727 — Drug Interactions table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Pimobendan — Both are PDE inhibitors — theoretical additive effect, use cautiously together
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 1060–1061; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 726–727 — Drug Interactions table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Pharmacokinetics5
Bioavailability — ~50% (dog) — higher than in humans
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 1060–1061; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 726–727 — Pharmacokinetics table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Volume of distribution — ~5.2 L/kg (dog) vs. 1.2 L/kg (human)
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 1060–1061; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 726–727 — Pharmacokinetics table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Half-life — ~6h (dog, significant interpatient variability)
Other speciesNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Other species · Plumb's Veterinary Drug Handbook, 7th ed., p. 1060–1061; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 726–727 — Pharmacokinetics table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Metabolism — Hepatic (CYP3A4/2C9)
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 1060–1061; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 726–727 — Pharmacokinetics table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Elimination — Hepatic/fecal predominant
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 1060–1061; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 726–727 — Pharmacokinetics table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Pregnancy / lactation considerations1
No teratogenicity/embryotoxicity in rat/rabbit studies at high doses. Human FDA category B. Unknown if excreted in milk.
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 1060–1061; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 726–727 — Pregnancy & Lactation · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Literature references19
References are linked to this drug. Species applicability is not recorded here, so the species filter does not narrow this list. Imported dates do not retain their original precision; confirm dates in the original citation.
- Phosphodiesterase Type 5 Inhibitors as Chemical Hazards in Honey and Honey-Based Products.
Study summary not available in the imported record. Open the original citation to review the study.
- An eco-friendly HPLC method for simultaneous analysis of sildenafil and sodium benzoate in pulmonary arterial hypertension suspension dosage monitoring.
Study summary not available in the imported record. Open the original citation to review the study.
- Effects of administration of sildenafil citrate and amino acids on selected physiological, blood gas and biochemical parameters in pregnant twin-bearing sheep in late gestation.
Study summary not available in the imported record. Open the original citation to review the study.
- Effects of Sildenafil administration on placentome dynamics, uterine and umbilical blood flow patterns in relation to nitric oxide and vascular endothelial growth factor in advanced pregnant Hegazi goats.
Study summary not available in the imported record. Open the original citation to review the study.
- Population Pharmacokinetics of Sildenafil in Dogs With Naturally Occurring Pulmonary Hypertension.
Study summary not available in the imported record. Open the original citation to review the study.
Sources: PubMed, National Library of Medicine; openFDA, U.S. Food and Drug Administration; Plumb DC. Plumb's Veterinary Drug Handbook. 7th ed. PharmaVet Inc; 2011.
Owner information handout
Plain-language medication information to review with the owner. Open the handout to print it or download a PDF.