Pharmacology
Periostat contains doxycycline hyclate which is a semi-synthetic tetracycline. Doxycycline is an inhibitor of collagenase activity. Studies have shown that doxycycline reduces the elevated collagenase activity in the gingival crevicular fluid of patients with chronic adult periodontitis, in an action unrelated to its antibacterial mode of action. The clinical significance of these findings is not known.
Indications
Periostat is indicated for use as an adjunct to scaling and root planing to promote attachment level gain and to reduce pocket depth in patients with adult periodontitis.
Precautions
Because tetracyclines have been shown to depress plasma prothrombin activity, patients who are on anticoagulant therapy may require downward adjustment of their anticoagulant dosage.
Since bacterial antibiotics, such as the tetracycline class of antibiotics, may interfere with the bactericidal action of members of the β-lactam (e.g. penicillin) class of antibiotics, it is not advisable to administer these antibiotics concomitantly.
Absorption of doxycycline is impaired by antacids containing aluminum, calcium, or magnesium, and iron-containing preparations. Absorption is also impaired by bismuth subsalicylate.
Barbiturates, carbamazepine, and phenytoin decrease the half-life of doxycycline.
The concurrent use of tetracycline and Penthrane (methoxy-fluorane) has been reported to result in fatal renal toxicity.
Concurrent use of doxycycline may render oral contraceptives less effective.
In long-term therapy, periodic laboratory evaluations of organ systems, including hematopoietic, renal, and hepatic studies should be performed.
False elevations of urinary catecholamine levels may occur due to interference with the fluorescence test.
Supplied
Each white capsule, imprinted with TM Periostat 20 mg contains: doxycycline hyclate equivalent to doxycycline 20 mg. Bottles of 100. Store at controlled room temperature between 15 and 30°C and dispense in tight, light-resistant containers, protected from excessive humidity.
Contraindications
This drug is contraindicated in persons who have shown hypersensitivity to any of the tetracyclines, and in patients with myasthenia gravis. Periostat should not be used during tooth development (second half of pregnancy, infancy and in childhood).
Warnings
Teratogenic Effects: Pregnancy Category D. Results from animal studies indicate that doxycycline crosses the placenta and is found in fetal tissues.
Adverse Effects
Adverse Reactions in Clinical Trials of Periostat: In clinical trials of adult patients with periodontal disease 213 patients received Periostat 20 mg BID over a 9-12 month period. The most frequent adverse reactions occurring in studies involving treatment with Periostat or placebo are listed in Table 1.
Overdose
In case of overdosage, discontinue medication, treat symptomatically and institute supportive measures. Dialysis does not alter serum half-life and thus would not be of benefit in treating cases of overdose.
Dosage
The dosage of Periostat differs from that of doxycycline used to treat infections. Exceeding the recommended dosage may result in an increased incidence of side effects including the development of resistant microorganisms.
Periostat 20 mg twice daily as an adjunct following scaling and root planing may be administered for up to 9 months. Safety beyond 12 months and efficacy beyond 9 months have not been established.
Periostat should be administered at least one hour prior to morning and evening meals. Administration of adequate amounts of fluid along with the capsules is recommended to wash down the drug and reduce the risk of esophageal irritation and ulceration.
