Rectogesic Adverse Reactions

Headache is the most common reaction to treatment with glyceryl trinitrate. These are usually mild and usually occur after the first few applications only. In a small number of patients headaches may be severe or persist. If headaches persist the dose should be reduced (see Dosage & Administration). If the headaches continue to occur or are severe, treatment should be withdrawn. Rectogesic may also cause fainting or dizziness, particularly in the elderly.
Incontinence is also a possible adverse reaction, although this has not been reported to date, and should be completely reversible on withdrawal of the drug.
Clinical studies: In patients treated with Rectogesic 4 mg/g Rectal Ointment, the most common treatment related adverse reaction was dose-related headache which occurred with an incidence of 57%.
Adverse reactions from clinical studies are displayed by system organ class in the table as follows. Within the system organ class, the adverse reactions are listed by frequency using the following groupings: very common (> 1/10), common (>1/100 <1/10), uncommon (>1/1000 <1/100). (See table.)

Click on icon to see table/diagram/image

Adverse reactions to glyceryl trinitrate 2% ointment (used in the prophylaxis of angina pectoris) are generally dose-related and almost all of these reactions are the result of vasodilator activity. Headache, which may be severe, is the most commonly reported side effect. In the Phase III clinical trials with Rectogesic 4 mg/g Rectal Ointment the incidence of mild, moderate and severe headache was 18%, 25% and 20%. Patients with a previous history of migraine or recurrent headache were at a higher risk of developing headache during treatment. Headache may be recurrent with each daily dose, especially at higher doses. Headache can be treated with mild analgesics e.g. paracetamol and in general is reversible on discontinuation of treatment.
Transient episodes of light-headedness, occasionally related to blood pressure changes, also may occur. Hypotension occurs infrequently, but in some patients may be severe enough to warrant discontinuation of therapy. Syncope, crescendo angina and rebound hypertension have been reported but are uncommon. Allergic reactions to glyceryl trinitrate are uncommon, and the great majority of those reported have been cases of contact dermatitis or fixed drug eruptions occurring in patients receiving glyceryl trinitrate in ointments or patches. There have been a few reports of genuine anaphylactoid reactions and these reactions can probably occur in patients receiving glyceryl trinitrate by any route. Extremely rarely, ordinary doses of organic nitrates have caused methaemoglobinaemia in normal-seeming patients. Flush has been observed as a rare adverse reaction for other products containing glyceryl trinitrate.