What should I do if I miss a dose of my medication?

What to Do If You Miss a Medication Dose

The action you should take when missing a medication dose depends critically on the specific medication type and how much time has elapsed since the scheduled dose. For most medications, take the missed dose as soon as you remember on the same day, but never double up doses to compensate for missed ones. 1, 2

General Principles for Missed Doses

Timing-Based Decision Framework

For most oral medications, the key threshold is whether you remember within the same day:

• If remembered on the same day: Take the missed dose as soon as possible and continue with your regular schedule 1, 2
• If remembered the next day: Skip the missed dose entirely and resume your normal schedule—do not double the next dose 1, 2
• Never take double doses to make up for missed medications, as this increases risk of adverse effects without providing therapeutic benefit 1, 2

Critical Medication-Specific Instructions

Hormonal Contraceptives (Birth Control Pills)

Combined oral contraceptives require different actions based on precise timing:

One Pill Late (<24 hours)

• Take the late pill immediately 3, 4
• Continue regular schedule 3, 4
• No backup contraception needed 3, 4
• Emergency contraception not usually needed unless pills were missed earlier in the cycle 3

One Pill Missed (24-48 hours)

• Take the most recent missed pill immediately 3, 4
• Continue taking remaining pills at usual time, even if taking two pills the same day 3, 4
• Use backup contraception (condoms) or avoid intercourse for 7 consecutive days 3, 4

Two or More Pills Missed (≥48 hours)

• Take the most recent missed pill immediately and discard other missed pills 3, 4
• Continue regular schedule 3, 4
• Use backup contraception for 7 consecutive days 3, 4
• If missed during first week AND unprotected intercourse occurred in previous 5 days, consider emergency contraception 3
• If missed during last week of hormonal pills (days 15-21), skip the hormone-free interval and start a new pack immediately 3

Important caveat: Higher-dose pills (30 μg ethinyl estradiol) provide better ovulation suppression than lower-dose options (20 μg) when pills are missed, making them more forgiving of nonadherence 3, 4

Progestin-Only Pills (Mini-Pills)

These require stricter timing than combined pills:

• If >3 hours late (>27 total hours since previous dose): Take one pill immediately, continue regular schedule, use backup contraception for 2 consecutive days, and consider emergency contraception if recent unprotected intercourse 3
• Progestin-only pills have a narrower window because they rely on cervical mucus effects that dissipate rapidly 3

Anticoagulants (Blood Thinners)

For warfarin specifically:

• Take the missed dose as soon as remembered on the same day 1
• Do not double the daily dose to make up for missed doses 1
• Contact your physician for guidance 1
• The anticoagulant effect persists beyond 24 hours, providing some buffer 1

Critical warning: Missing anticoagulant doses can significantly increase stroke risk, particularly in patients with atrial fibrillation or mechanical heart valves 3

Injectable Contraceptives (Depo-Provera)

• If <2 weeks late (<15 weeks after previous injection): Proceed with injection, no backup method needed 3
• If ≥2 weeks late: Treat as new start, use backup contraception for 7 consecutive days, consider emergency contraception 3

Contraceptive Patch and Vaginal Ring

For delayed application/insertion:

• If <48 hours late: Apply/insert immediately, keep same change day, no backup needed 3
• If ≥48 hours late: Apply/insert immediately, use backup contraception for 7 consecutive days, consider emergency contraception if appropriate 3
• If missed during week 3: Skip hormone-free interval and start new cycle immediately 3

Special Circumstances Requiring Immediate Action

When to Contact Your Healthcare Provider

Contact your provider immediately if:

• You miss multiple doses of critical medications (anticoagulants, antiepileptics, immunosuppressants, HIV medications) 3
• You experience symptoms that might indicate loss of therapeutic effect 3
• You're unsure about medication-specific instructions 1, 2
• You have a pattern of frequently missing doses, which may require regimen simplification or alternative formulations 3

Vomiting or Severe Diarrhea

For oral contraceptives:

• If vomiting/diarrhea occurs within 3 hours of taking a pill, treat as a missed dose 3
• Take another pill as soon as tolerated 3
• Use backup contraception until 2 days after symptoms resolve (progestin-only) or for 7 consecutive days (combined pills) 3

Strategies to Prevent Missed Doses

Evidence-based adherence tools include: 3

• Weekly pill boxes filled in advance 3
• Smartphone alarms set for each dosing time 3
• Mobile health applications with reminders and adherence tracking 3
• Linking medication times to daily routines (meals, bedtime) 3
• 90-day prescription refills to reduce pharmacy visits 3

Common pitfall: Day-marked blister packs are helpful, but electronic monitoring with feedback is more effective for patients with suspected nonadherence 3

Critical Safety Considerations

The risk from missed doses varies dramatically by medication class:

• High-risk medications where single missed doses can cause harm: anticoagulants, antiepileptics, immunosuppressants, HIV medications, insulin 3
• Moderate-risk medications: antihypertensives, antidepressants, hormonal contraceptives 3
• Lower-risk medications: vitamins, supplements, some chronic disease medications 2

Key principle: Once-daily dosing regimens generally result in better adherence than twice-daily regimens, though the clinical impact of missing a single dose from a once-daily regimen may be greater due to larger fluctuations in drug levels 3