Drug interactions between Nitrogard and Viagra
| Results for the following 2 drugs: |
|---|
| Nitrogard (nitroglycerin) |
| Viagra (sildenafil) |
Interactions between your selected drugs
nitroglycerin ↔ sildenafil
Applies to:Nitrogard (nitroglycerin) and Viagra (sildenafil)
CONTRAINDICATED: Phosphodiesterase-5 (PDE5) inhibitors may potentiate the hypotensive effect of organic nitrates. Significant hypotension may result from use of the combination. The mechanism involves peripheral vasodilation secondary to enhanced levels of cyclic guanosine monophosphate (cGMP) in vascular smooth muscle cells, as PDE5 inhibitors prevent degradation of cGMP while nitrates promote its synthesis. Single oral doses of the PDE5 inhibitors sildenafil (100 mg) and vardenafil (20 mg) have produced mean maximum decreases in supine blood pressure (systolic/diastolic) of approximately 8.4/5.5 and 7/8 mmHg, respectively, compared to placebo. The decrease in blood pressure was most notable approximately 1 to 2 hours after sildenafil dosing and 1 to 4 hours after vardenafil dosing and was additive with that produced by nitrates. Tadalafil 20 mg administered to healthy male subjects produced no significant difference in supine or standing blood pressure compared to placebo, although the drug did potentiate the hypotensive effect of nitrates at a dosage of 5 to 20 mg.
MANAGEMENT: The use of PDE5 inhibitors in patients receiving organic nitrates or other nitric oxide donors, either regularly or intermittently, is considered contraindicated. A suitable time interval following administration of sildenafil or vardenafil for the safe administration of nitrates has not been determined. For tadalafil, data from a clinical pharmacology study suggest that at least 48 hours should elapse after the last dose of tadalafil before nitrate administration is considered, should it be deemed medically necessary in a life-threatening situation. Even then, nitrates should only be administered under close medical supervision with appropriate hemodynamic monitoring. Therefore, patients should be advised to seek immediate medical attention if they experience anginal chest pain after taking tadalafil or another PDE5 inhibitor.
See also...
Drug Interaction Classification
The classifications below are a guideline only. The relevance of a particular drug interaction to a specific patient is difficult to determine using this tool alone given the large number of variables that may apply.
| Major | Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit. |
| Moderate | Moderately clinically significant. Usually avoid combinations; use it only under special circumstances. |
| Minor | Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan. |
Do not stop taking any medications without consulting your healthcare provider.
Disclaimer: Every effort has been made to ensure that the information provided by Multum is accurate, up-to-date, and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. Multum's drug information does not endorse drugs, diagnose patients, or recommend therapy. Multum's drug information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug of drug combination is safe, effective, or appropriate for any given patient. Multum Information Services, Inc. does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. Copyright 2000-2012 Multum Information Services, Inc. The information in contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse, or pharmacist.
