Nitroglycerin ointment has emerged as a well-established, guideline-recommended therapy for postoperative pain management and acute spasm relief in anorectal surgery—particularly following hemorrhoidectomy. Its efficacy in reducing anal sphincter hypertonia and associated pain is supported by robust clinical evidence and endorsed across multiple national and international practice guidelines. However, its safety profile is highly dependent on appropriate patient selection, precise dosing, and strict adherence to administration protocols—not inherent drug toxicity.
Clinical experience consistently shows that adverse events are rare when the medication is used under medical supervision and according to established standards. Most reported complications—including transient headache, mild hypotension, or brief elevation in intraocular pressure—occur in settings of nonadherence: patients omitting relevant medical history (e.g., glaucoma or baseline hypotension), applying excessive amounts, or using the ointment without professional guidance. For example, one case involved a patient with untreated primary open-angle glaucoma who self-administered nitroglycerin ointment and experienced a short-lived rise in intraocular pressure; symptoms resolved promptly upon discontinuation. Another patient developed orthostatic dizziness after thick application post-hemorrhoidectomy but achieved full symptom control without side effects once switched to the recommended thin-layer regimen.
Optimal use requires a structured, four-step clinical workflow. First, prescribers must conduct a thorough pre-treatment assessment—including screening for absolute contraindications such as uncontrolled glaucoma, symptomatic hypotension, severe anemia, circulatory shock, or concurrent use of phosphodiesterase-5 inhibitors (e.g., sildenafil, tadalafil). Patients must be explicitly encouraged to disclose all comorbidities and current medications. Second, timing and technique matter: application should follow warm sitz bath (40°C for 5–10 minutes), with the perianal area thoroughly dried prior to a thin, targeted layer (0.2–0.5 g) applied either topically around the anus or intrarectally. Patients should remain supine for 10 minutes afterward to minimize orthostatic effects. Third, dosing is typically once or twice daily, strictly limited to the shortest effective duration—prolonged or unsupervised use increases risk of tolerance and systemic vasodilation. Finally, vigilant post-application monitoring is essential: patients should be counseled to recognize early signs of systemic absorption—including headache, lightheadedness, facial flushing, or visual changes—and discontinue use immediately if severe symptoms (e.g., marked hypotension, chest tightness, or blurred vision) occur.
The principal pharmacologic risks stem from nitroglycerin’s potent vasodilatory action. When absorbed systemically—especially via overapplication or compromised skin barriers—it can induce dose-dependent reductions in systemic vascular resistance and blood pressure. This effect is markedly amplified when co-administered with antihypertensives, other nitrates, or PDE5 inhibitors—a combination explicitly contraindicated in regulatory labeling and clinical guidelines. Importantly, nitroglycerin ointment is not a general-purpose “hemorrhoid cream.” It does not treat underlying hemorrhoidal pathology, nor does it replace surgical or definitive medical management. Rather, it serves a specific, evidence-based role in multimodal analgesia—acting primarily as a smooth-muscle relaxant to alleviate sphincter spasm–related pain.
Its clinical utility is firmly anchored in consensus recommendations. The 2023 *Expert Consensus on Perioperative Management of Hemorrhoids* (World Federation of Chinese Medicine Societies) assigns nitroglycerin ointment a Grade A recommendation (Level 1 evidence) for post-hemorrhoidectomy pain control. Similarly, the *2024 American Society of Colon and Rectal Surgeons (ASCRS) Clinical Practice Guidelines* endorse topical 0.2% nitroglycerin ointment both as part of multimodal analgesia after surgical hemorrhoidectomy and as a first-line conservative option for symptomatic thrombosed external hemorrhoids—particularly in patients declining or medically unfit for excision. Additional support comes from the *2020 Expert Consensus on Day-Case Hemorrhoid Surgery*, which integrates nitroglycerin into standardized same-day discharge protocols, and the *2025 Integrated TCM–Western Medicine Guidelines for Hemorrhoids*, which highlight its role in minimizing opioid requirements while maintaining low adverse event rates.
Recognizing contraindications is critical to safe prescribing. Absolute exclusions include known hypersensitivity to nitroglycerin or ointment excipients; active or uncontrolled angle-closure or narrow-angle glaucoma; systolic blood pressure below 90 mmHg; severe anemia or decompensated cardiovascular shock; and concurrent use of sildenafil, vardenafil, tadalafil, or avanafil. Common adverse effects—such as mild headache, transient dizziness, or facial warmth—are usually self-limiting and resolve within 24–48 hours with supportive measures (hydration, rest, avoidance of sudden position changes). Less common local reactions—including perianal burning or pruritus—warrant immediate discontinuation and gentle cleansing. Rare but serious manifestations—such as profound hypotension, syncope, or visual disturbances—require urgent evaluation and cessation of therapy.
To ensure therapeutic integrity and patient safety, nitroglycerin ointment must be dispensed exclusively through licensed pharmacies—either hospital-based or verified online platforms adhering to national pharmaceutical distribution regulations. Self-prescribing, dose escalation, or combination with other vasodilators without clinician oversight significantly elevates risk without enhancing benefit. Ultimately, the clinical value of this agent lies not in its molecular properties alone, but in disciplined implementation: rigorous patient assessment, precise application technique, time-limited use, and proactive symptom monitoring. When integrated thoughtfully into perioperative care pathways, nitroglycerin ointment remains a safe, effective, and guideline-endorsed cornerstone of modern anorectal pain management.