Undesirable effects are listed below by system organ class and frequency. Frequencies are defined as follows: very common (≥ 1/10); common (≥ 1/100 to < 1/10); uncommon (≥ 1/1 000 to < 1/100); rare (≥ 1/10 000 to < 1/1 000) or very rare (< 1/10 000).
| Blood and lymphatic system disorders | |
| Very rare | Methaemoglobinaemia |
| Psychiatric disorders | |
| Very rare | Restlessness |
| Nervous system disorders | |
| Very common | Headache** |
| Common | Dizziness Drowsiness |
| Uncommon | Syncope |
| Very rare | Cerebral ischaemia**** |
| Cardiac disorders |
| Common | Tachycardia |
| Uncommon | Enhanced angina pectoris symptoms*** Bradycardia Cyanosis |
| Vascular disorders |
| Common | Orthostatic hypotension* |
| Uncommon | Facial flushing Circulatory collapse |
| Gastrointestinal disorders |
| Uncommon | Nausea Vomiting |
| Very rare | Heartburn Halitosis |
| Respiratory, thoracic and mediastinal disorders |
| Very rare | Impairment of respiration |
| Skin and subcutaneous tissue disorders |
| Very rare | Exfoliative dermatitis Drug rash |
| General disorders and administration site conditions |
| Common | Asthenia |
| Investigations |
| Common | Blood pressure decreased* |
*Particularly upon initiation of therapy and following an increase in dose. Occasionally, the first dose, or the first elevated dose may cause a blood pressure drop and/or postural hypotension with reflex tachycardia, dizziness and weakness.
**Headache due to vasodilatation may occur at the beginning of the treatment.
***Sporadically, in cases with extreme blood pressure reduction, the treatment may aggravate the symptoms of angina pectoris (paradoxical nitrate reaction).
****Glyceryl trinitrate-induced hypotension may cause cerebral ischaemia.
The following side effects occur in approximately 30-40% of patients: taste disturbance (metallic taste), mild burning or stinging sensation in the mouth or tongue, and palpitations.
These are usually mild and disappear within a few minutes.
In some cases hypersensitivity reactions, icluding allergic skin reactions may appear.
Sometimes bradyarrhythmia occurs.
Sometimes collapse occurs.
Large dose of glyceryl trinitrate may cause vomiting, cyanosis, restlessness, methaemoglobinaemia and impairment of respiration.
During treatment with glyceryl trinitrate, temporary hypoxemia may occur due to a relative
redistribution of the blood flow in hypoventilated alveolar areas.
Reporting of suspected adverse reactions
Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via the Yellow Card Scheme (website: www.mhra.gov.uk/yellowcard) or search for MHRA Yellow Card in the Google Play or Apple App store.