Felodipine
| Evidence Level: L2 | Predicted Indications: 7 |
Table of Contents
Felodipine: From Hypertension/Chronic Angina to Prinzmetal’s (Variant) Angina
One-Sentence Summary
Felodipine is a dihydropyridine calcium channel blocker (CCB) whose established use — evident throughout the supporting literature — is in hypertension and chronic stable angina pectoris. Among seven candidate indications flagged by the TxGNN model, Prinzmetal’s (variant) angina stands out as the only one backed by direct, drug-specific randomized controlled trials, with 4 RCTs and 5 supporting reviews/case reports identified. The remaining six candidates (including the model’s #1-ranked prediction) have little to no supporting evidence and are held at screening stage.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Hypertension / Chronic stable angina pectoris (established CCB class use; no structured India label text available — see Data Gaps) |
| Predicted New Indication | Prinzmetal’s (variant) angina |
| TxGNN Prediction Score | 99.07% |
| Evidence Level | L2 |
| India Market Status | Not Marketed |
| Number of Registrations | 0 |
| Recommended Decision | Proceed with Guardrails |
Why is This Prediction Reasonable?
Detailed mechanism-of-action data for felodipine is not available in the evidence pack (flagged as a High-severity data gap). Based on the supporting literature itself, felodipine is a vasoselective dihydropyridine calcium channel blocker (CCB) — the same pharmacological class as nifedipine — and its blood-pressure-lowering and antianginal effects are attributed to inhibition of calcium influx into vascular smooth muscle, producing arterial vasodilation (PMID 3154329, 14689111).
Felodipine’s established indications (hypertension, chronic stable/exertional angina) and the candidate indication (Prinzmetal’s angina) sit on the same pathophysiological axis: both involve abnormal vascular or coronary smooth-muscle tone. Prinzmetal’s angina specifically results from focal coronary artery spasm rather than fixed atherosclerotic obstruction.
Because CCBs directly relax coronary smooth muscle, they are already considered a first-line, mechanistically direct treatment for coronary vasospasm (PMID 7728649: “calcium channel blockers are drugs of first choice in this syndrome”). Felodipine’s applicability here is therefore not a speculative cross-disease leap but a class-consistent extension, corroborated by head-to-head trials against nifedipine (PMID 1746458, 8013514) showing comparable antiischemic efficacy.
Clinical Trial Evidence
Currently no related clinical trials are registered on ClinicalTrials.gov or ICTRP for felodipine in Prinzmetal’s angina. The evidence below is derived instead from published RCTs and reviews indexed in PubMed (pre-registry era studies, 1988–1995).
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 1746458 | 1991 | RCT | American Journal of Cardiology | In 30 patients, once-daily felodipine (10–20 mg) matched the antiischemic effect of nifedipine four-times-daily on 24h Holter monitoring for Prinzmetal’s angina |
| 8013514 | 1994 | RCT | European Heart Journal | Once-daily extended-release felodipine 20 mg prevented ergonovine-induced myocardial ischaemia in 14 patients with variant angina |
| 7744087 | 1995 | RCT | European Heart Journal | Double-blind crossover trial (n=43): felodipine ER 10mg once daily improved exercise duration comparably to nifedipine SR twice daily vs placebo |
| 2909138 | 1989 | RCT/Cohort | American Journal of Cardiology | Felodipine reduced hyperventilation-induced ischemic attacks in variant angina |
| 14689111 | 2003 | Review | Herz | CCBs improve endothelial function and are effective across hypertensive and anginal syndromes |
| 7728649 | 1995 | Review | Canadian Journal of Cardiology | CCBs, via antivasospastic properties, are first-choice therapy for Prinzmetal’s angina; felodipine reviewed specifically |
| 3345765 | 1988 | Case series/Observational | European Heart Journal | Documents exercise-induced ST-elevation consistent with coronary spasm in Prinzmetal’s angina |
| 19052677 | 2008 | Case report | Canadian Journal of Cardiology | Coronary vasospasm complicated by polymorphic ventricular tachycardia |
| 15222138 | 2004 | Case report | Orvosi Hetilap | Drug-induced Prinzmetal angina case, illustrating the vasospasm mechanism the CCB class targets |
Other Predicted Indications Evaluated (Screened / On Hold)
The evidence pack scored six additional TxGNN candidates for felodipine; none currently support action:
| Rank | Predicted Indication | TxGNN Score | Evidence Level | Recommendation | Note |
|---|---|---|---|---|---|
| 1 | Pulmonary hypertension, unclear multifactorial mechanism | 99.91% | L5 | Hold | No trials or literature; model score only |
| 2 | Pulmonary hypertension owing to lung disease/hypoxia | 99.91% | L5 | Hold | 20 literature hits, all on hypoxia biology unrelated to felodipine; guidelines caution against CCBs in this PH group |
| 3 | Malignant renovascular hypertension | 99.90% | L4 | Hold | Only one unrelated case report (post-adrenalectomy) |
| 4 | Malignant hypertensive renal disease | 99.90% | L5 | Hold | No supporting evidence |
| 5 | Braddock syndrome | 99.88% | L5 | Hold | No plausible mechanistic link; likely knowledge-graph noise |
| 6 | Chronic pulmonary heart disease (cor pulmonale) | 99.19% | L3 | Research Question | 3 hemodynamic studies show felodipine lowers pulmonary vascular resistance in COPD/CHF, but selectivity and safety versus PH-specific agents remain unresolved |
This spread illustrates that TxGNN’s raw ranking score does not track evidence strength — the top-ranked candidate (#1) has zero supporting studies, while the lower-ranked Prinzmetal’s angina candidate has direct RCT support.
India Market Information
Felodipine is currently not marketed in India under this evidence pack (0 registrations, no license records available), so no product/registration table can be generated.
Safety Considerations
- Drug Interactions: 246 total interactions identified. One Major-level interaction: Dolasetron. Notable Moderate-level interactions include corticosteroids (hydrocortisone, triamcinolone, dexamethasone, betamethasone, budesonide), CYP3A4-related agents (clarithromycin, cimetidine, aprepitant), SGLT2 inhibitors (canagliflozin, dapagliflozin, empagliflozin), cannabinoids (dronabinol, nabilone), aspirin, morphine, bupropion, magnesium sulfate, and calcium salts (calcium phosphate, calcium acetate).
Structured key warnings and contraindications are not available in this evidence pack and must be obtained from the official package insert before clinical use.
Conclusion and Next Steps
Decision: Proceed with Guardrails
Rationale: Felodipine’s efficacy in Prinzmetal’s (variant) angina is supported by 4 RCTs and consistent with an already-established, class-wide CCB mechanism (coronary vasospasm relief) — this is the strongest evidence-backed candidate in the set. However, two structural blockers remain: the drug is not currently registered/marketed in India, and package-insert-level safety data (warnings, contraindications) is entirely missing (flagged Blocking severity), which prevents a full safety review.
To proceed, the following is needed:
- Official India-approved (or reference-market) package insert for warnings and contraindications (resolves DG001, Blocking)
- Confirmation of India registration pathway, since felodipine currently has 0 licenses on file
- Formal mechanism-of-action documentation from DrugBank/product literature (resolves DG002)
- If pursued clinically: a defined dosing/monitoring protocol specific to vasospastic angina, distinguishing it from felodipine’s existing hypertension/stable-angina use
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.