Theophylline as a Treatment for Children With Pseudohypoparathyroidism Type 1a (Albright Hereditary Osteodystrophy)

Inclusion Criteria:

1. Age 10 to 21 years old

2. English proficiency

3. Clinical and genetic diagnosis of PHP1a

Exclusion Criteria:

1. Use of a PDE inhibitor in the past 30 days

2. History of a seizure disorder unrelated to hypocalcemia

3. History of a cardiac arrhythmia (not including bradycardia)

4. History of hepatic insufficiency

5. AST or ALT >2x upper limit of normal

6. Total bilirubin >1.5 x upper limit of normal (unless patient has a diagnosis of
Gilbert's syndrome and no other causes leading to hyperbilirubinemia are identified)

7. Congestive heart failure

8. Cigarette use in the past 30 days

9. Alcohol use within the past 24 hours

10. Current pregnancy

11. Untreated hypothyroidism (defined as free T4 level < 0.6 ng/dL or TSH >10 mcU/mL)

12. Active peptic ulcer disease

13. Fever >101 degrees in the past 24 hours

14. Current use of medications known to effect theophylline levels (listed below)

15. Severe sleep apnea requiring BiPAP

Drugs with clinically significant drug interactions with theophylline:

- Allopurinol

- Cimetidine

- Ciprofloxacin

- Clarithromycin

- Enoxacin

- Ephedrine

- Erythromycin

- Estrogen

- Flurazepam

- Fluvoxamine

- Lithium

- Lorazepam

- Methotrexate

- Midazolam

- Pentoxifylline

- Propranolol

- Rifampin

- Sulfinpyrazone

- Tacrine

- Thiabendazole

- Ticlopidine

- Troleandomycin

- Verapamil