Injections into an artery must be strictly avoided. Intravenous injections of Tandegyl must be given slowly (over 2 to 3 minutes).
Tandegyl is an H1-receptor antagonist. It belongs to the benzhydryl ether group of antihistamines. Tandegyl inhibits selectively the histamine receptors of the H1 type and reduces capillary permeability. It exerts a potent antihistaminic and antipruritic effect with a rapid onset and long duration of action up to 12 hours.
Composition
Tandegyl contains Clemastine as the hydrogen fumarate and is available in the following forms and strengths;
- Tandegyl Tablets 1mg/tablet
- Tandegyl Syrup 0.25mg/5ml
- Tandegyl Injection (2ml) 1mg/ml
Pharmacokinetics
After oral administration, Tandegyl (clemastine) is almost completely absorbed from the gastrointestinal tract. Peak plasma concentrations are attained within 2 to 4 hours. The antihistaminic activity of the drug reaches its peak after 5 to 7 hours; it usually persists for 10 to 12 hours, and in some cases, for up to 24 hours.
Plasma protein binding of Tandegyl (clemastine) amounts to 95%. Elimination from plasma occurs biphasically, with half-lives of 3.6±0.9 hours and 37±16 hours. Tandegyl (clemastine) undergoes extensive metabolism in the liver. The major route of metabolite excretion (45 to 65%) is through the kidneys into the urine, where only trace amounts of the parent compound are found. In lactating women, small amounts of the drug may pass into breast milk.
Precautions
Particularly when given by the parenteral route, Tandegyl may have a sedative effect. Care should therefore be exercised by patients when driving a vehicle and operating machinery.
Antihistamines should be used with caution for patients with narrow-angle glaucoma, stenosing peptic ulcer, pyloroduodenal obstruction, or prostatic hypertrophy with urinary retention and bladder neck obstruction.
Tandegyl should not be given during pregnancy and breastfeeding unless strictly indicated.
