What is the recommended dosing time for a female patient of reproductive age taking norethindrone (progestin)?

Norethindrone Dosing Time

Norethindrone must be taken at the same time every day without interruption to achieve maximum contraceptive effectiveness. 1

Timing Requirements

• Take one tablet daily at exactly the same time each day, with no breaks between pill packs 1
• The FDA label explicitly states that norethindrone tablets must be taken "at the same time" every day for maximum contraceptive effectiveness 1
• Administration is continuous with no hormone-free intervals, unlike combined oral contraceptives 1

Critical Timing Window

• If a pill is taken 3 or more hours late, use backup contraception (condoms) for the next 48 hours 1
• This narrow window reflects norethindrone's short half-life (8.5 ± 1.5 hours) and rapid clearance from the body 2
• Peak serum levels occur approximately 2 hours after ingestion, then decline rapidly 2

Practical Implementation

• Choose a consistent time that fits your daily routine (e.g., morning with breakfast, bedtime) to maximize adherence 1
• Set a daily alarm or use medication reminder apps to ensure consistent timing 1
• Keep backup pills accessible if you travel across time zones or have irregular schedules 1

Pharmacokinetic Rationale

The strict timing requirement exists because:

• Norethindrone reaches peak concentration at 2 hours post-ingestion (18.3 ± 4.8 ng/ml) 2
• The drug undergoes biphasic elimination with an initial rapid decay (half-life 1.2 ± 0.1 hours) followed by slower elimination (half-life 8.5 ± 1.5 hours) 2
• Serum levels accumulate gradually during continuous use, starting at ~1 ng/ml and increasing by 0.12 ng/ml per day up to 3.5 ng/ml by day 21 2
• This accumulation pattern requires daily dosing at consistent intervals to maintain therapeutic contraceptive levels 2

Common Pitfalls to Avoid

• Never skip days or take "pill holidays" - progestin-only pills require continuous daily administration unlike combined oral contraceptives that have placebo weeks 1
• Do not assume a 12-hour window is acceptable - the 3-hour window is much narrower than combined oral contraceptives due to norethindrone's pharmacokinetics 1
• Remember that vomiting or severe diarrhea within 3-4 hours of taking the pill may reduce absorption and require backup contraception 1